144 results on '"Acton, W. Joe F."'
Search Results
2. Emission estimates and inventories of non-methane volatile organic compounds from anthropogenic burning sources in India
- Author
-
Stewart, Gareth J., Nelson, Beth S., Acton, W. Joe F., Vaughan, Adam R., Hopkins, James R., Yunus, Siti S.M., Hewitt, C. Nicholas, Wild, Oliver, Nemitz, Eiko, Gadi, Ranu, Sahu, Lokesh K., Mandal, Tuhin K., Gurjar, Bhola R., Rickard, Andrew R., Lee, James D., and Hamilton, Jacqueline F.
- Published
- 2021
- Full Text
- View/download PDF
3. Impact of HO2 aerosol uptake on radical levels and O3 production during summertime in Beijing
- Author
-
Dyson, Joanna E., primary, Whalley, Lisa K., additional, Slater, Eloise J., additional, Woodward-Massey, Robert, additional, Ye, Chunxiang, additional, Lee, James D., additional, Squires, Freya, additional, Hopkins, James R., additional, Dunmore, Rachel E., additional, Shaw, Marvin, additional, Hamilton, Jacqueline F., additional, Lewis, Alastair C., additional, Worrall, Stephen D., additional, Bacak, Asan, additional, Mehra, Archit, additional, Bannan, Thomas J., additional, Coe, Hugh, additional, Percival, Carl J., additional, Ouyang, Bin, additional, Hewitt, C. Nicholas, additional, Jones, Roderic L., additional, Crilley, Leigh R., additional, Kramer, Louisa J., additional, Acton, W. Joe F., additional, Bloss, William J., additional, Saksakulkrai, Supattarachai, additional, Xu, Jingsha, additional, Shi, Zongbo, additional, Harrison, Roy M., additional, Kotthaus, Simone, additional, Grimmond, Sue, additional, Sun, Yele, additional, Xu, Weiqi, additional, Yue, Siyao, additional, Wei, Lianfang, additional, Fu, Pingqing, additional, Wang, Xinming, additional, Arnold, Stephen R., additional, and Heard, Dwayne E., additional
- Published
- 2023
- Full Text
- View/download PDF
4. Extreme Concentrations of Nitric Oxide Control Daytime Oxidation and Quench Nocturnal Oxidation Chemistry in Delhi during Highly Polluted Episodes
- Author
-
Nelson, Beth S., Bryant, Daniel J., Alam, Mohammed S., Sommariva, Roberto, Bloss, William J., Newland, Mike J., Drysdale, Will S., Vaughan, Adam R., Acton, W. Joe F., Hewitt, C. Nicholas, Crilley, Leigh R., Swift, Stefan J., Edwards, Pete M., Lewis, Alastair C., Langford, Ben, Nemitz, Eiko, Shivani, Gadi, Ranu, Gurjar, Bhola R., Heard, Dwayne E., Whalley, Lisa K., Şahin, Ülkü A., Beddows, David C. S., Hopkins, James R., Lee, James D., Rickard, Andrew R., Hamilton, Jacqueline F., Nelson, Beth S., Bryant, Daniel J., Alam, Mohammed S., Sommariva, Roberto, Bloss, William J., Newland, Mike J., Drysdale, Will S., Vaughan, Adam R., Acton, W. Joe F., Hewitt, C. Nicholas, Crilley, Leigh R., Swift, Stefan J., Edwards, Pete M., Lewis, Alastair C., Langford, Ben, Nemitz, Eiko, Shivani, Gadi, Ranu, Gurjar, Bhola R., Heard, Dwayne E., Whalley, Lisa K., Şahin, Ülkü A., Beddows, David C. S., Hopkins, James R., Lee, James D., Rickard, Andrew R., and Hamilton, Jacqueline F.
- Abstract
Delhi, India, suffers from periods of very poor air quality, but little is known about the chemical production of secondary pollutants in this highly polluted environment. During the postmonsoon period in 2018, extremely high nighttime concentrations of NOx (NO and NO2) and volatile organic compounds (VOCs) were observed, with median NOx mixing ratios of ∼200 ppbV (maximum of ∼700 ppbV). A detailed chemical box model constrained to a comprehensive suite of speciated VOC and NOx measurements revealed very low nighttime concentrations of oxidants, NO3, O3, and OH, driven by high nighttime NO concentrations. This results in an atypical NO3 diel profile, not previously reported in other highly polluted urban environments, significantly perturbing nighttime radical oxidation chemistry. Low concentrations of oxidants and high nocturnal primary emissions coupled with a shallow boundary layer led to enhanced early morning photo-oxidation chemistry. This results in a temporal shift in peak O3 concentrations when compared to the premonsoon period (12:00 and 15:00 local time, respectively). This shift will likely have important implications on local air quality, and effective urban air quality management should consider the impacts of nighttime emission sources during the postmonsoon period.
- Published
- 2023
5. Supplementary material to "Impact of HO2 aerosol uptake on radical levels and O3 production during summertime in Beijing"
- Author
-
Dyson, Joanna E., primary, Whalley, Lisa K., additional, Slater, Eloise J., additional, Woodward-Massey, Robert, additional, Ye, Chunxiang, additional, Lee, James D., additional, Squires, Freya, additional, Hopkins, James R., additional, Dunmore, Rachel E., additional, Shaw, Marvin, additional, Hamilton, Jacqueline F., additional, Lewis, Alastair C., additional, Worrall, Stephen D., additional, Bacak, Asan, additional, Mehra, Archit, additional, Bannan, Thomas J., additional, Coe, Hugh, additional, Percival, Carl J., additional, Ouyang, Bin, additional, Hewitt, C. Nicholas, additional, Jones, Roderic L., additional, Crilley, Leigh R., additional, Kramer, Louisa J., additional, Acton, W. Joe F., additional, Bloss, William J., additional, Saksakulkrai, Supattarachai, additional, Xu, Jingsha, additional, Shi, Zongbo, additional, Harrison, Roy M., additional, Kotthaus, Simone, additional, Grimmond, Sue, additional, Sun, Yele, additional, Xu, Weiqi, additional, Yue, Siyao, additional, Wei, Lianfang, additional, Fu, Pingqing, additional, Wang, Xinming, additional, Arnold, Stephen R., additional, and Heard, Dwayne E., additional
- Published
- 2022
- Full Text
- View/download PDF
6. Impact of HO2 aerosol uptake on radical levels and O3 production during summertime in Beijing
- Author
-
Dyson, Joanna E., primary, Whalley, Lisa K., additional, Slater, Eloise J., additional, Woodward-Massey, Robert, additional, Ye, Chunxiang, additional, Lee, James D., additional, Squires, Freya, additional, Hopkins, James R., additional, Dunmore, Rachel E., additional, Shaw, Marvin, additional, Hamilton, Jacqueline F., additional, Lewis, Alastair C., additional, Worrall, Stephen D., additional, Bacak, Asan, additional, Mehra, Archit, additional, Bannan, Thomas J., additional, Coe, Hugh, additional, Percival, Carl J., additional, Ouyang, Bin, additional, Hewitt, C. Nicholas, additional, Jones, Roderic L., additional, Crilley, Leigh R., additional, Kramer, Louisa J., additional, Acton, W. Joe F., additional, Bloss, William J., additional, Saksakulkrai, Supattarachai, additional, Xu, Jingsha, additional, Shi, Zongbo, additional, Harrison, Roy M., additional, Kotthaus, Simone, additional, Grimmond, Sue, additional, Sun, Yele, additional, Xu, Weiqi, additional, Yue, Siyao, additional, Wei, Lianfang, additional, Fu, Pingqing, additional, Wang, Xinming, additional, Arnold, Stephen R., additional, and Heard, Dwayne E., additional
- Published
- 2022
- Full Text
- View/download PDF
7. Biogenic and anthropogenic sources of isoprene and monoterpenes and their secondary organic aerosol in Delhi, India
- Author
-
Bryant, Daniel J., Nelson, Beth S., Swift, Stefan J., Budisulistiorini, Sri Hapsari, Drysdale, Will S., Vaughan, Adam R., Newland, Mike J., Hopkins, James R., Cash, James M., Langford, Ben, Nemitz, Eiko, Acton, W. Joe F., Hewitt, C. Nicholas, Mandal, Tuhin, Gurjar, Bhola R., Shivani, Gadi, Ranu, Lee, James D., Rickard, Andrew R., and Hamilton, Jacqueline F.
- Subjects
Atmospheric Science ,Atmospheric Sciences - Abstract
Isoprene and monoterpene emissions to the atmosphere are generally dominated by biogenic sources. The oxidation of these compounds can lead to the production of secondary organic aerosol; however the impact of this chemistry in polluted urban settings has been poorly studied. Isoprene and monoterpenes can form secondary organic aerosol (SOA) heterogeneously via anthropogenic–biogenic interactions, resulting in the formation of organosulfate (OS) and nitrooxy-organosulfate (NOS) species. Delhi, India, is one of the most polluted cities in the world, but little is known about the emissions of biogenic volatile organic compounds (VOCs) or the sources of SOA. As part of the DELHI-FLUX project, gas-phase mixing ratios of isoprene and speciated monoterpenes were measured during pre- and post-monsoon measurement campaigns in central Delhi. Nocturnal mixing ratios of the VOCs were substantially higher during the post-monsoon (isoprene: (0.65±0.43) ppbv; limonene: (0.59±0.11) ppbv; α-pinene: (0.13±0.12) ppbv) than the pre-monsoon (isoprene: (0.13±0.18) ppbv; limonene: 0.011±0.025 (ppbv); α-pinene: 0.033±0.009) period. At night, isoprene and monoterpene concentrations correlated strongly with CO during the post-monsoon period. Filter samples of particulate matter less than 2.5 µm in diameter (PM2.5) were collected and the OS and NOS content analysed using ultra-high-performance liquid chromatography tandem mass spectrometry (UHPLC-MS2). Inorganic sulfate was shown to facilitate the formation of isoprene OS species across both campaigns. Sulfate contained within OS and NOS species was shown to contribute significantly to the sulfate signal measured via AMS. Strong nocturnal enhancements of NOS species were observed across both campaigns. The total concentration of OS and NOS species contributed an average of (2.0±0.9) % and (1.8±1.4) % to the total oxidized organic aerosol and up to a maximum of 4.2 % and 6.6 % across the pre- and post-monsoon periods, respectively. Overall, this study provides the first molecular-level measurements of SOA derived from isoprene and monoterpene in Delhi and demonstrates that both biogenic and anthropogenic sources of these compounds can be important in urban areas.
- Published
- 2022
8. PM1 composition and source apportionment at two sites in Delhi, India, across multiple seasons
- Author
-
Reyes-Villegas, Ernesto, Panda, Upasana, Darbyshire, Eoghan, Cash, James M., Joshi, Rutambhara, Langford, Ben, Di Marco, Chiara F., Mullinger, Neil J., Alam, Mohammed S., Crilley, Leigh R., Rooney, Daniel J., Acton, W. Joe F., Drysdale, Will, Nemitz, Eiko, Flynn, Michael, Voliotis, Aristeidis, McFiggans, Gordon, Coe, Hugh, Lee, James, Hewitt, C. Nicholas, Heal, Mathew R., Gunthe, Sachin S., Mandal, Tuhin K., Gurjar, Bhola R., Shivani, Gadi, Ranu, Singh, Siddhartha, Soni, Vijay, and Allan, James D.
- Subjects
aerosol mass spectrometry ,Source apportionment ,urban air quality ,air pollution ,positive matrix factorization ,megacities ,atmospheric aerosol ,Atmospheric Sciences ,PM1 - Abstract
Air pollution in urban environments has been shown to have a negative impact on air quality and human health, particularly in megacities. Over recent decades, Delhi, India, has suffered high atmospheric pollution, with significant particulate matter (PM) concentrations as a result of anthropogenic activities. Organic aerosols (OAs) are composed of thousands of different chemical species and are one of the main constituents of submicron particles. However, quantitative knowledge of OA composition, their sources and their processes in urban environments is still limited. This is important particularly in India, as Delhi is a massive, inhomogeneous conurbation, where we would expect the apportionment and concentrations to vary depending on where in Delhi the measurements/source apportionment is performed, indicating the need for multisite measurements. This study presents the first multisite analysis carried out in India over different seasons, with a focus on identifying OA sources. The measurements were taken during 2018 at two sites in Delhi, India. One site was located at the India Meteorological Department, New Delhi (ND). The other site was located at the Indira Gandhi Delhi Technical University for Women, Old Delhi (OD). Non-refractory submicron aerosol (NR-PM1) concentrations (ammonium, nitrate, sulfate, chloride and organic aerosols) of four aerosol mass spectrometers were analysed. Collocated measurements of volatile organic compounds, black carbon, NOx and CO were performed. Positive matrix factorisation (PMF) analysis was performed to separate the organic fraction, identifying a number of conventional factors: hydrocarbon-like OAs (HOAs) related to traffic emissions, biomass burning OAs (BBOAs), cooking OAs (COAs) and secondary OAs (SOAs). A composition-based estimate of PM1 is defined by combining black carbon (BC) and NR-PM1 (C-PM1= BC + NR-PM1). No significant difference was observed in C-PM1 concentrations between sites, OD (142 ± 117 µg m−3) compared to ND (123 ± 71 µg m3), from post-monsoon measurements. A wider variability was observed between seasons, where pre-monsoon and monsoon showed C-PM1 concentrations lower than 60 µg m−3. A seasonal variation in C-PM1 composition was observed; SO42- showed a high contribution over pre-monsoon and monsoon seasons, while NO3- and Cl− had a higher contribution in winter and post-monsoon. The main primary aerosol source was from traffic, which is consistent with the PMF analysis and Aethalometer model analysis. Thus, in order to reduce PM1 concentrations in Delhi through local emission controls, traffic emission control offers the greatest opportunity. PMF–aerosol mass spectrometer (AMS) mass spectra will help to improve future aerosol source apportionment studies. The information generated in this study increases our understanding of PM1 composition and OA sources in Delhi, India. Furthermore, the scientific findings provide significant information to strengthen legislation that aims to improve air quality in India.
- Published
- 2021
9. Biogenic and anthropogenic sources of isoprene and monoterpenes and their secondary organic aerosol in Delhi, India.
- Author
-
Bryant, Daniel J., Nelson, Beth S., Swift, Stefan J., Budisulistiorini, Sri Hapsari, Drysdale, Will S., Vaughan, Adam R., Newland, Mike J., Hopkins, James R., Cash, James M., Langford, Ben, Nemitz, Eiko, Acton, W. Joe F., Hewitt, C. Nicholas, Mandal, Tuhin, Gurjar, Bhola R., Shivani, Gadi, Ranu, Lee, James D., Rickard, Andrew R., and Hamilton, Jacqueline F.
- Subjects
CARBONACEOUS aerosols ,LIQUID chromatography-mass spectrometry ,ISOPRENE ,MICROBIOLOGICAL aerosols ,MONOTERPENES ,ACCELERATOR mass spectrometry ,VOLATILE organic compounds ,AEROSOLS - Abstract
Isoprene and monoterpene emissions to the atmosphere are generally dominated by biogenic sources. The oxidation of these compounds can lead to the production of secondary organic aerosol; however the impact of this chemistry in polluted urban settings has been poorly studied. Isoprene and monoterpenes can form secondary organic aerosol (SOA) heterogeneously via anthropogenic–biogenic interactions, resulting in the formation of organosulfate (OS) and nitrooxy-organosulfate (NOS) species. Delhi, India, is one of the most polluted cities in the world, but little is known about the emissions of biogenic volatile organic compounds (VOCs) or the sources of SOA. As part of the DELHI-FLUX project, gas-phase mixing ratios of isoprene and speciated monoterpenes were measured during pre- and post-monsoon measurement campaigns in central Delhi. Nocturnal mixing ratios of the VOCs were substantially higher during the post-monsoon (isoprene: (0.65±0.43) ppbv; limonene: (0.59±0.11) ppbv; α -pinene: (0.13±0.12) ppbv) than the pre-monsoon (isoprene: (0.13±0.18) ppbv; limonene: 0.011±0.025 (ppbv); α -pinene: 0.033±0.009) period. At night, isoprene and monoterpene concentrations correlated strongly with CO during the post-monsoon period. Filter samples of particulate matter less than 2.5 µm in diameter (PM 2.5) were collected and the OS and NOS content analysed using ultra-high-performance liquid chromatography tandem mass spectrometry (UHPLC-MS 2). Inorganic sulfate was shown to facilitate the formation of isoprene OS species across both campaigns. Sulfate contained within OS and NOS species was shown to contribute significantly to the sulfate signal measured via AMS. Strong nocturnal enhancements of NOS species were observed across both campaigns. The total concentration of OS and NOS species contributed an average of (2.0±0.9) % and (1.8±1.4) % to the total oxidized organic aerosol and up to a maximum of 4.2 % and 6.6 % across the pre- and post-monsoon periods, respectively. Overall, this study provides the first molecular-level measurements of SOA derived from isoprene and monoterpene in Delhi and demonstrates that both biogenic and anthropogenic sources of these compounds can be important in urban areas. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
10. Evaluating the sensitivity of radical chemistry and ozone formation to ambient VOCs and NOₓ in Beijing
- Author
-
Whalley, Lisa K., Slater, Eloise J., Woodward-Massey, Robert, Ye, Chunxiang, Lee, James D., Squires, Freya, Hopkins, James R., Dunmore, Rachel E., Shaw, Marvin, Hamilton, Jacqueline F., Lewis, Alastair C., Mehra, Archit, Worrall, Stephen D., Bacak, Asan, Bannan, Thomas J., Coe, Hugh, Percival, Carl J., Ouyang, Bin, Jones, Roderic L., Crilley, Leigh R., Kramer, Louisa J., Bloss, William J., Vu, Tuan, Kotthaus, Simone, Grimmond, Sue, Sun, Yele, Xu, Weiqi, Yue, Siyao, Ren, Lujie, Acton, W. Joe F., Hewitt, C. Nicholas, Wang, Xinming, Fu, Pingqing, and Heard, Dwayne E.
- Abstract
Measurements of OH, HO2, complex RO2 (alkene- and aromatic-related RO2) and total RO2 radicals taken during the integrated Study of AIR Pollution PROcesses in Beijing (AIRPRO) campaign in central Beijing in the summer of 2017, alongside observations of OH reactivity, are presented. The concentrations of radicals were elevated, with OH reaching up to 2.8×107moleculecm−3, HO2 peaking at 1×109moleculecm−3 and the total RO2 concentration reaching 5.5×109moleculecm−3. OH reactivity (k(OH)) peaked at 89 s−1 during the night, with a minimum during the afternoon of ≈22s−1 on average. An experimental budget analysis, in which the rates of production and destruction of the radicals are compared, highlighted that although the sources and sinks of OH were balanced under high NO concentrations, the OH sinks exceeded the known sources (by 15 ppbv h−1) under the very low NO conditions (
- Published
- 2021
11. Comprehensive organic emission profiles, secondary organic aerosol production potential, and OH reactivity of domestic fuel combustion in Delhi, India
- Author
-
Stewart, Gareth J., Nelson, Beth S., Acton, W. Joe F., Vaughan, Adam R., Hopkins, James R., Yunus, Siti S.M., Hewitt, C. Nicholas, Nemitz, Eiko, Mandal, Tuhin K., Gadi, Ranu, Sahu, Lokesh K., Rickard, Andrew R., Lee, James D., Hamilton, Jacqueline F., Stewart, Gareth J., Nelson, Beth S., Acton, W. Joe F., Vaughan, Adam R., Hopkins, James R., Yunus, Siti S.M., Hewitt, C. Nicholas, Nemitz, Eiko, Mandal, Tuhin K., Gadi, Ranu, Sahu, Lokesh K., Rickard, Andrew R., Lee, James D., and Hamilton, Jacqueline F.
- Abstract
Domestic solid fuel combustion is a major source of organic compounds to the atmosphere in gas and aerosol phases; however, large uncertainties exist in the current understanding of the gas-to-particle partitioning and the drivers of the reactivity of these emissions. This study developed comprehensive, model-ready organic emission profiles for domestic solid fuel combustion sources collected from Delhi, India. It also examined the organic species responsible for secondary organic aerosol (SOA) production potential and hydroxyl radical (OH) reactivity of these emissions. The profiles spanned the entire volatility range, including non-methane volatile organic compounds (NMVOCs, effective saturation concentration, C* = 3 × 106 to 1011 μg m−3), intermediate-volatility organic compounds (IVOCs, C* = 300 to 3 × 106 μg m−3), semi-volatile organic compounds (SVOCs, C* = 0.3–300 μg m−3) as well as low- and extremely low-volatility organic compounds (L/ELVOCs, where LVOC C* ≤ 0.3 μg m−3). The profiles predicted that IVOCs would contribute significantly to SOA production and that the combustion of fuel wood and charcoal released some of the smallest proportions of SVOCs. A model was developed to examine SOA production from burning emissions which estimated that phenolics would contribute 10–70% of the SOA. Furanics were the most important reactive species, contributing 9–48% of the OH reactivity and 9–58% of the SOA. Different combustion sources were also compared, with emissions from fuel wood, crop residue, cow dung cake and municipal solid waste (MSW) burning shown to be 30, 90, 120 and 230 times more reactive with the OH radical than emissions from liquefied petroleum gas (LPG) fuel. This study also estimated 3–4 times more SOA from cow dung cake combustion and 6–7 more from MSW combustion than fuel wood under comparable combustion conditions. The results of this study suggest that emissions from the combustion of domestic solid fuel sources in Delhi have the potential to
- Published
- 2021
12. Using highly time-resolved online mass spectrometry to examine biogenic and anthropogenic contributions to organic aerosol in Beijing
- Author
-
Mehra, Archit, Canagaratna, Manjula, Bannan, Thomas J., Worrall, Stephen D., Bacak, Asan, Priestley, Michael, Liu, Dantong, Zhao, Jian, Xu, Weiqi, Sun, Yele, Hamilton, Jacqueline F., Squires, Freya A., Lee, James, Bryant, Daniel J., Hopkins, James R., Elzein, Atallah, Budisulistiorini, Sri Hapsari, Cheng, Xi, Chen, Qi, Wang, Yuwei, Wang, Lin, Stark, Harald, Krechmer, Jordan E., Brean, James, Slater, Eloise, Whalley, Lisa, Heard, Dwayne, Ouyang, Bin, Acton, W. Joe F., Hewitt, C. Nicholas, Wang, Xinming, Fu, Pingqing, Jayne, John, Worsnop, Douglas, Allan, James, Percival, Carl, Coe, Hugh, Mehra, Archit, Canagaratna, Manjula, Bannan, Thomas J., Worrall, Stephen D., Bacak, Asan, Priestley, Michael, Liu, Dantong, Zhao, Jian, Xu, Weiqi, Sun, Yele, Hamilton, Jacqueline F., Squires, Freya A., Lee, James, Bryant, Daniel J., Hopkins, James R., Elzein, Atallah, Budisulistiorini, Sri Hapsari, Cheng, Xi, Chen, Qi, Wang, Yuwei, Wang, Lin, Stark, Harald, Krechmer, Jordan E., Brean, James, Slater, Eloise, Whalley, Lisa, Heard, Dwayne, Ouyang, Bin, Acton, W. Joe F., Hewitt, C. Nicholas, Wang, Xinming, Fu, Pingqing, Jayne, John, Worsnop, Douglas, Allan, James, Percival, Carl, and Coe, Hugh
- Abstract
Organic aerosols, a major constituent of fine particulate mass in megacities, can be directly emitted or formed from secondary processing of biogenic and anthropogenic volatile organic compound emissions. The complexity of volatile organic compound emission sources, speciation and oxidation pathways leads to uncertainties in the key sources and chemistry leading to formation of organic aerosol in urban areas. Historically, online measurements of organic aerosol composition have been unable to resolve specific markers of volatile organic compound oxidation, while offline analysis of markers focus on a small proportion of organic aerosol and lack the time resolution to carry out detailed statistical analysis required to study the dynamic changes in aerosol sources and chemistry. Here we use data collected as part of the joint UK–China Air Pollution and Human Health (APHH-Beijing) collaboration during a field campaign in urban Beijing in the summer of 2017 alongside laboratory measurements of secondary organic aerosol from oxidation of key aromatic precursors (1,3,5-trimethyl benzene, 1,2,4-trimethyl benzene, propyl benzene, isopropyl benzene and 1-methyl naphthalene) to study the anthropogenic and biogenic contributions to organic aerosol. For the first time in Beijing, this study applies positive matrix factorisation to online measurements of organic aerosol composition from a time-of-flight iodide chemical ionisation mass spectrometer fitted with a filter inlet for gases and aerosols (FIGAERO-ToF-I-CIMS). This approach identifies the real-time variations in sources and oxidation processes influencing aerosol composition at a near-molecular level. We identify eight factors with distinct temporal variability, highlighting episodic differences in OA composition attributed to regional influences and in situ formation. These have average carbon numbers ranging from C5–C9 and can be associated with oxidation of anthropogenic aromatic hydrocarbons alongside biogenic emissi
- Published
- 2021
13. Evaluating the sensitivity of radical chemistry and ozone formation to ambient VOCs and NOx in Beijing
- Author
-
Whalley, Lisa, Slater, Eloise, Woodward-Massey, Robert, Ye, Chunxiang, Lee, James D., Squires, Freya, Hopkins, James R., Dunmore, Rachel E., Shaw, Marvin, Hamilton, Jacqueline F., Lewis, Alastair C., Mehra, Archit, Worrall, Stephen David, Bacak, Asan, Bannan, Thomas J., Coe, Hugh, Ouyang, Bin, Jones, Roderic L., Crilley, Leigh R., Kramer, Louisa J., Bloss, William J., Vu, Tuan, Kotthaus, Simone, Grimmond, Sue, Sun, Yele, Xu, Weiqi, Yue, Siyao, Ren, Lujie, Acton, W Joe F, Hewitt, C N, Wang, Xinming, Fu, Pingqing, Heard, Dwayne E., Whalley, Lisa, Slater, Eloise, Woodward-Massey, Robert, Ye, Chunxiang, Lee, James D., Squires, Freya, Hopkins, James R., Dunmore, Rachel E., Shaw, Marvin, Hamilton, Jacqueline F., Lewis, Alastair C., Mehra, Archit, Worrall, Stephen David, Bacak, Asan, Bannan, Thomas J., Coe, Hugh, Ouyang, Bin, Jones, Roderic L., Crilley, Leigh R., Kramer, Louisa J., Bloss, William J., Vu, Tuan, Kotthaus, Simone, Grimmond, Sue, Sun, Yele, Xu, Weiqi, Yue, Siyao, Ren, Lujie, Acton, W Joe F, Hewitt, C N, Wang, Xinming, Fu, Pingqing, and Heard, Dwayne E.
- Published
- 2021
14. Seasonal analysis of submicron aerosol in Old Delhi using high-resolution aerosol mass spectrometry: chemical characterisation, source apportionment and new marker identification
- Author
-
Cash, James M., Langford, Ben, Di Marco, Chiara, Mullinger, Neil J., Allan, James, Reyes-Villegas, Ernesto, Joshi, Ruthambara, Heal, Mathew R., Acton, W. Joe F., Hewitt, C. Nicholas, Misztal, Pawel K., Drysdale, Will, Mandal, Tuhin K., Shivani, Shivani, Gadi, Ranu, Gurjar, Bhola Ram, Nemitz, Eiko, Cash, James M., Langford, Ben, Di Marco, Chiara, Mullinger, Neil J., Allan, James, Reyes-Villegas, Ernesto, Joshi, Ruthambara, Heal, Mathew R., Acton, W. Joe F., Hewitt, C. Nicholas, Misztal, Pawel K., Drysdale, Will, Mandal, Tuhin K., Shivani, Shivani, Gadi, Ranu, Gurjar, Bhola Ram, and Nemitz, Eiko
- Abstract
We present the first real-time composition of submicron particulate matter (PM1) in Old Delhi using high-resolution aerosol mass spectrometry (HR-AMS). Old Delhi is one of the most polluted locations in the world, and PM1 concentrations reached ∼ 750 µg m−3 during the most polluted period, the post-monsoon period, where PM1 increased by 188 % over the pre-monsoon period. Sulfate contributes the largest inorganic PM1 mass fraction during the pre-monsoon (24 %) and monsoon (24 %) periods, with nitrate contributing most during the post-monsoon period (8 %). The organics dominate the mass fraction (54 %–68 %) throughout the three periods, and, using positive matrix factorisation (PMF) to perform source apportionment analysis of organic mass, two burning-related factors were found to contribute the most (35 %) to the post-monsoon increase. The first PMF factor, semi-volatility biomass burning organic aerosol (SVBBOA), shows a high correlation with Earth observation fire counts in surrounding states, which links its origin to crop residue burning. The second is a solid fuel OA (SFOA) factor with links to local open burning due to its high composition of polyaromatic hydrocarbons (PAHs) and novel AMS-measured marker species for polychlorinated dibenzodioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs). Two traffic factors were resolved: one hydrocarbon-like OA (HOA) factor and another nitrogen-rich HOA (NHOA) factor. The N compounds within NHOA were mainly nitrile species which have not previously been identified within AMS measurements. Their PAH composition suggests that NHOA is linked to diesel and HOA to compressed natural gas and petrol. These factors combined make the largest relative contribution to primary PM1 mass during the pre-monsoon and monsoon periods while contributing the second highest in the post-monsoon period. A cooking OA (COA) factor shows strong links to the secondary factor, semi-volatility oxygenated OA (SVOOA). Correlations with co-located v
- Published
- 2021
15. Emissions of non-methane volatile organic compounds from combustion of domestic fuels in Delhi, India
- Author
-
Stewart, Gareth J., Acton, W. Joe F., Nelson, Beth S., Vaughan, Adam R., Hopkins, James R., Arya, Rahul, Mondal, Arnab, Jangirh, Ritu, Ahlawat, Sakshi, Yadav, Lokesh, Sharma, Sudhir K., Dunmore, Rachel E., Yunus, Siti S.M., Hewitt, C. Nicholas, Nemitz, Eiko, Mullinger, Neil, Gadi, Ranu, Sahu, Lokesh K., Tripathi, Nidhi, Rickard, Andrew R., Lee, James D., Mandal, Tuhin K., Hamilton, Jacqueline F., Stewart, Gareth J., Acton, W. Joe F., Nelson, Beth S., Vaughan, Adam R., Hopkins, James R., Arya, Rahul, Mondal, Arnab, Jangirh, Ritu, Ahlawat, Sakshi, Yadav, Lokesh, Sharma, Sudhir K., Dunmore, Rachel E., Yunus, Siti S.M., Hewitt, C. Nicholas, Nemitz, Eiko, Mullinger, Neil, Gadi, Ranu, Sahu, Lokesh K., Tripathi, Nidhi, Rickard, Andrew R., Lee, James D., Mandal, Tuhin K., and Hamilton, Jacqueline F.
- Abstract
2Twenty-nine different fuel types used in residential dwellings in northern India were collected from across Delhi (76 samples in total). Emission factors of a wide range of non-methane volatile organic compounds (NMVOCs) (192 compounds in total) were measured during controlled burning experiments using dual-channel gas chromatography with flame ionisation detection (DC-GC-FID), two-dimensional gas chromatography (GC × GC-FID), proton-transfer-reaction time-of-flight mass spectrometry (PTR-ToF-MS) and solid-phase extraction two-dimensional gas chromatography with time-of-flight mass spectrometry (SPE-GC × GC–ToF-MS). On average, 94 % speciation of total measured NMVOC emissions was achieved across all fuel types. The largest contributors to emissions from most fuel types were small non-aromatic oxygenated species, phenolics and furanics. The emission factors (in g kg−1) for total gas-phase NMVOCs were fuelwood (18.7, 4.3–96.7), cow dung cake (62.0, 35.3–83.0), crop residue (37.9, 8.9–73.8), charcoal (5.4, 2.4–7.9), sawdust (72.4, 28.6–115.5), municipal solid waste (87.3, 56.6–119.1) and liquefied petroleum gas (5.7, 1.9–9.8). The emission factors measured in this study allow for better characterisation, evaluation and understanding of the air quality impacts of residential solid-fuel combustion in India.
- Published
- 2021
16. Emissions of intermediate-volatility and semi-volatile organic compounds from domestic fuels used in Delhi, India
- Author
-
Stewart, Gareth J., Nelson, Beth S., Acton, W. Joe F., Vaughan, Adam R., Farren, Naomi J., Hopkins, James R., Ward, Martyn W., Swift, Stefan J., Arya, Rahul, Mondal, Arnab, Jangirh, Ritu, Ahlawat, Sakshi, Yadav, Lokesh, Sharma, Sudhir K., Yunus, Siti S.M., Hewitt, C. Nicholas, Nemitz, Eiko, Mullinger, Neil, Gadi, Ranu, Sahu, Lokesh K., Tripathi, Nidhi, Rickard, Andrew R., Lee, James D., Mandal, Tuhin K., Hamilton, Jacqueline F., Stewart, Gareth J., Nelson, Beth S., Acton, W. Joe F., Vaughan, Adam R., Farren, Naomi J., Hopkins, James R., Ward, Martyn W., Swift, Stefan J., Arya, Rahul, Mondal, Arnab, Jangirh, Ritu, Ahlawat, Sakshi, Yadav, Lokesh, Sharma, Sudhir K., Yunus, Siti S.M., Hewitt, C. Nicholas, Nemitz, Eiko, Mullinger, Neil, Gadi, Ranu, Sahu, Lokesh K., Tripathi, Nidhi, Rickard, Andrew R., Lee, James D., Mandal, Tuhin K., and Hamilton, Jacqueline F.
- Abstract
Biomass burning emits significant quantities of intermediate-volatility and semi-volatile organic compounds (I/SVOCs) in a complex mixture, probably containing many thousands of chemical species. These components are significantly more toxic and have poorly understood chemistry compared to volatile organic compounds routinely quantified in ambient air; however, analysis of I/SVOCs presents a difficult analytical challenge. The gases and particles emitted during the test combustion of a range of domestic solid fuels collected from across Delhi were sampled and analysed. Organic aerosol was collected onto Teflon (PTFE) filters, and residual low-volatility gases were adsorbed to the surface of solid-phase extraction (SPE) discs. A new method relying on accelerated solvent extraction (ASE) coupled to comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry (GC × GC–ToF-MS) was developed. This highly sensitive and powerful analytical technique enabled over 3000 peaks from I/SVOC species with unique mass spectra to be detected. A total of 15 %–100 % of gas-phase emissions and 7 %–100 % of particle-phase emissions were characterised. The method was analysed for suitability to make quantitative measurements of I/SVOCs using SPE discs. Analysis of SPE discs indicated phenolic and furanic compounds were important for gas-phase I/SVOC emissions and levoglucosan to the aerosol phase. Gas- and particle-phase emission factors for 21 polycyclic aromatic hydrocarbons (PAHs) were derived, including 16 compounds listed by the US EPA as priority pollutants. Gas-phase emissions were dominated by smaller PAHs. The new emission factors were measured (mg kg−1) for PAHs from combustion of cow dung cake (615), municipal solid waste (1022), crop residue (747), sawdust (1236), fuelwood (247), charcoal (151) and liquefied petroleum gas (56). The results of this study indicate that cow dung cake and municipal solid waste burning are likely to be significant PAH sou
- Published
- 2021
17. Avoiding high ozone pollution in Delhi, India
- Author
-
Chen, Ying, Beig, Gufran, Archer-Nicholls, Scott, Drysdale, Will, Acton, W. Joe F., Lowe, Douglas, Nelson, Beth, Lee, James, Ran, Liang, Wang, Yu, Wu, Zhijun, Sahu, Saroj Kumar, Sokhi, Ranjeet S., Singh, Vikas, Gadi, Ranu, Hewitt, C. Nicholas, Nemitz, Eiko, Archibald, Alex, McFiggins, Gordon, Wild, Oliver, Chen, Ying, Beig, Gufran, Archer-Nicholls, Scott, Drysdale, Will, Acton, W. Joe F., Lowe, Douglas, Nelson, Beth, Lee, James, Ran, Liang, Wang, Yu, Wu, Zhijun, Sahu, Saroj Kumar, Sokhi, Ranjeet S., Singh, Vikas, Gadi, Ranu, Hewitt, C. Nicholas, Nemitz, Eiko, Archibald, Alex, McFiggins, Gordon, and Wild, Oliver
- Abstract
Surface ozone is a major pollutant threatening public health, agricultural production and natural ecosystems. While measures to improve air quality in megacities such as Delhi are typically aimed at reducing levels of particulate matter (PM), ozone could become a greater threat if these measures focus on PM alone, as some air pollution mitigation steps can actually lead to an increase in surface ozone. A better understanding of the factors controlling ozone production in Delhi and the impact that PM mitigation measures have on ozone is therefore critical for improving air quality. Here, we combine in-situ observations and model analysis to investigate the impact of PM reduction on the non-linear relationship between volatile organic compounds (VOC), nitrogen oxides (NOx) and ozone. In-situ measurements of NOx, VOC, and ozone were conducted in Delhi during the APHH-India programme in summer (June) and winter (November) 2018. We observed hourly averaged ozone concentrations in the city of up to 100 ppbv in both seasons. We performed sensitivity simulations with a chemical box model to explore the impacts of PM on the non-linear VOC-NOx-ozone relationship in each season through its effect on aerosol optical depth (AOD). We find that ozone production is limited by VOC in both seasons, and is particularly sensitive to solar radiation in winter. Reducing NOx alone increases ozone, such that a 50% reduction in NOx emissions leads to 10-50% increase in surface ozone. In contrast, reducing VOC emissions can reduce ozone efficiently, such that a 50% reduction in VOC emissions leads to ~60% reduction in ozone. Reducing PM alone also increases ozone, especially in winter, by reducing its dimming effects on photolysis, such that a 50% reduction in AOD can increase ozone by 25% and it also enhances VOC-limitation. Our results highlight the importance of reducing VOC emissions alongside PM to limit ozone pollution, as well as benefitting control of PM pollution through reducing se
- Published
- 2021
18. Sources of non-methane hydrocarbons in surface air in Delhi, India
- Author
-
Stewart, Gareth J., Nelson, Beth S., Drysdale, Will S., Acton, W. Joe F., Vaughan, Adam R., Hopkins, James R., Dunmore, Rachel E., Hewitt, C. Nicholas, Nemitz, Eiko, Mullinger, Neil, Langford, Ben, Shivani, Shivani, Reyes-Villegas, Ernesto, Gadi, Ranu, Rickard, Andrew R., Lee, James D., Hamilton, Jacqueline F., Stewart, Gareth J., Nelson, Beth S., Drysdale, Will S., Acton, W. Joe F., Vaughan, Adam R., Hopkins, James R., Dunmore, Rachel E., Hewitt, C. Nicholas, Nemitz, Eiko, Mullinger, Neil, Langford, Ben, Shivani, Shivani, Reyes-Villegas, Ernesto, Gadi, Ranu, Rickard, Andrew R., Lee, James D., and Hamilton, Jacqueline F.
- Abstract
Rapid economic growth and development have exacerbated air quality problems across India, driven by many poorly understood pollution sources and understanding their relative importance remains critical to characterising the key drivers of air pollution. A comprehensive suite of measurements of 90 non-methane hydrocarbons (NMHCs) (C2–C14), including 12 speciated monoterpenes and higher molecular weight monoaromatics, were made at an urban site in Old Delhi during the pre-monsoon (28-May to 05-Jun 2018) and post-monsoon (11 to 27-Oct 2018) seasons using dual-channel gas chromatography (DC-GC-FID) and two-dimensional gas chromatography (GC×GC-FID). Significantly higher mixing ratios of NMHCs were measured during the post-monsoon campaign, with a mean night-time enhancement of around 6. Like with NOx and CO, strong diurnal profiles were observed for all NMHCs, except isoprene, with very high NMHC mixing ratios between 35–1485 ppbv. The sum of mixing ratios of benzene, toluene, ethylbenzene and xylenes (BTEX) routinely exceeded 100 ppbv at night during the post-monsoon period, with a maximum measured mixing ratio of monoaromatic species of 370 ppbv. The mixing ratio of highly reactive monoterpenes peaked at around 6 ppbv in the post-monsoon campaign and correlated strongly with anthropogenic NMHCs, suggesting a strong non-biogenic source in Delhi. A detailed source apportionment study was conducted which included regression analysis to CO, acetylene and other NMHCs, hierarchical cluster analysis, EPA UNMIX 6.0, principal component analysis/absolute principal component scores (PCA/APCS) and comparison with NMHC ratios (benzene/toluene and i-/n-pentane) in ambient samples to liquid and solid fuels. These analyses suggested the primary source of anthropogenic NMHCs in Delhi was from traffic emissions (petrol and diesel), with average mixing ratio contributions from Unmix and PCA/APCS models of 38% from petrol, 14% from diesel and 32% from liquified petroleum gas (LPG) with
- Published
- 2021
19. Low-NO atmospheric oxidation pathways in a polluted megacity
- Author
-
Newland, Mike J., Bryant, Daniel J., Dunmore, Rachel E., Bannan, Thomas J., Acton, W. Joe F., Langford, Ben, Hopkins, James R., Squires, Freya A., Dixon, William, Drysdale, William S., Ivatt, Peter D., Evans, Mathew J., Edwards, Peter M., Whalley, Lisa K., Heard, Dwayne E., Slater, Eloise J., Woodward-Massey, Robert, Ye, Chunxiang, Mehra, Archit, Worrall, Stephen D., Bacak, Asan, Coe, Hugh, Percival, Carl J., Hewitt, C. Nicholas, Lee, James D., Cui, Tianqu, Surratt, Jason D., Wang, Xinming, Lewis, Alastair C., Rickard, Andrew R., Hamilton, Jacqueline F., Newland, Mike J., Bryant, Daniel J., Dunmore, Rachel E., Bannan, Thomas J., Acton, W. Joe F., Langford, Ben, Hopkins, James R., Squires, Freya A., Dixon, William, Drysdale, William S., Ivatt, Peter D., Evans, Mathew J., Edwards, Peter M., Whalley, Lisa K., Heard, Dwayne E., Slater, Eloise J., Woodward-Massey, Robert, Ye, Chunxiang, Mehra, Archit, Worrall, Stephen D., Bacak, Asan, Coe, Hugh, Percival, Carl J., Hewitt, C. Nicholas, Lee, James D., Cui, Tianqu, Surratt, Jason D., Wang, Xinming, Lewis, Alastair C., Rickard, Andrew R., and Hamilton, Jacqueline F.
- Abstract
The impact of emissions of volatile organic compounds (VOCs) to the atmosphere on the production of secondary pollutants, such as ozone and secondary organic aerosol (SOA), is mediated by the concentration of nitric oxide (NO). Polluted urban atmospheres are typically considered to be “high-NO” environments, while remote regions such as rainforests, with minimal anthropogenic influences, are considered to be “low NO”. However, our observations from central Beijing show that this simplistic separation of regimes is flawed. Despite being in one of the largest megacities in the world, we observe formation of gas- and aerosol-phase oxidation products usually associated with low-NO “rainforest-like” atmospheric oxidation pathways during the afternoon, caused by extreme suppression of NO concentrations at this time. Box model calculations suggest that during the morning high-NO chemistry predominates (95 %) but in the afternoon low-NO chemistry plays a greater role (30 %). Current emissions inventories are applied in the GEOS-Chem model which shows that such models, when run at the regional scale, fail to accurately predict such an extreme diurnal cycle in the NO concentration. With increasing global emphasis on reducing air pollution, it is crucial for the modelling tools used to develop urban air quality policy to be able to accurately represent such extreme diurnal variations in NO to accurately predict the formation of pollutants such as SOA and ozone.
- Published
- 2021
20. Comprehensive organic emission profiles, secondary organic aerosol production potential, and OH reactivity of domestic fuel combustion in Delhi, India
- Author
-
Stewart, Gareth, Nelson, Beth S., Acton, W. Joe F., Vaughan, Adam Robert, Hopkins, James R., Yunus, Siti S. M., Hewitt, C N, Nemitz, Eiko, Mandal, Tuhin K., Gadi, Ranu, Sahu, Lokesh K., Rickard, Andrew, Lee, James D., Hamilton, Jacqueline F., Stewart, Gareth, Nelson, Beth S., Acton, W. Joe F., Vaughan, Adam Robert, Hopkins, James R., Yunus, Siti S. M., Hewitt, C N, Nemitz, Eiko, Mandal, Tuhin K., Gadi, Ranu, Sahu, Lokesh K., Rickard, Andrew, Lee, James D., and Hamilton, Jacqueline F.
- Abstract
Domestic solid fuel combustion is a major source of organic compounds to the atmosphere in gas and aerosol phases; however, large uncertainties exist in the current understanding of the gas-to-particle partitioning and the drivers of the reactivity of these emissions. This study developed comprehensive, model-ready organic emission profiles for domestic solid fuel combustion sources collected from Delhi, India. It also examined the organic species responsible for secondary organic aerosol (SOA) production potential and hydroxyl radical (OH) reactivity of these emissions. The profiles spanned the entire volatility range, including non-methane volatile organic compounds (NMVOCs, effective saturation concentration, C* 1⁄4 3 106 to 1011 mg m3), intermediate- volatility organic compounds (IVOCs, C* 1⁄4 300 to 3 106 mg m3), semi-volatile organic compounds (SVOCs, C* 1⁄4 0.3–300 mg m3) as well as low- and extremely low-volatility organic compounds (L/ELVOCs, where LVOC C* # 0.3 mg m3). The profiles predicted that IVOCs would contribute significantly to SOA production and that the combustion of fuel wood and charcoal released some of the smallest proportions of SVOCs. A model was developed to examine SOA production from burning emissions which estimated that phenolics would contribute 10–70% of the SOA. Furanics were the most important reactive species, contributing 9–48% of the OH reactivity and 9–58% of the SOA. Different combustion sources were also compared, with emissions from fuel wood, crop residue, cow dung cake and municipal solid waste (MSW) burning shown to be 30, 90, 120 and 230 times more reactive with the OH radical than emissions from liquefied petroleum gas (LPG) fuel. This study also estimated 3–4 times more SOA from cow dung cake combustion and 6–7 more from MSW combustion than fuel wood under comparable combustion conditions. The results of this study suggest that emissions from the combustion of domestic solid fuel sources in Delhi have the potential to
- Published
- 2021
21. Emissions of non-methane volatile organic compounds from combustion of domestic fuels in Delhi, India
- Author
-
Stewart, Gareth, Acton, W. Joe F., Nelson, Beth S., Vaughan, Adam Robert, Hopkins, James R., Arya, Rahul, Mondal, Arnab, Jangirh, Ritu, Ahlawat, Sakshi, Yadav, Lokesh, Sharma, Sudhir K., Dunmore, Rachel E., Yunus, Siti S. M., Hewitt, C N, Nemitz, Eiko, Mullinger, Neil, Gadi, Ranu, Sahu, Lokesh K., Tripathi, Nidhi, Rickard, Andrew, Lee, James D., Mandal, Tuhin K., Hamilton, Jacqueline F., Stewart, Gareth, Acton, W. Joe F., Nelson, Beth S., Vaughan, Adam Robert, Hopkins, James R., Arya, Rahul, Mondal, Arnab, Jangirh, Ritu, Ahlawat, Sakshi, Yadav, Lokesh, Sharma, Sudhir K., Dunmore, Rachel E., Yunus, Siti S. M., Hewitt, C N, Nemitz, Eiko, Mullinger, Neil, Gadi, Ranu, Sahu, Lokesh K., Tripathi, Nidhi, Rickard, Andrew, Lee, James D., Mandal, Tuhin K., and Hamilton, Jacqueline F.
- Abstract
Twenty-nine different fuel types used in residential dwellings in northern India were collected from across Delhi (76 samples in total). Emission factors of a wide range of non-methane volatile organic compounds (NMVOCs) (192 compounds in total) were measured during controlled burning experiments using dual-channel gas chromatography with flame ionisation detection (DC-GC-FID), two-dimensional gas chromatography (GC × GC-FID), proton-transfer-reaction time-of-flight mass spectrometry (PTR-ToF-MS) and solid-phase extraction two-dimensional gas chromatography with time-of-flight mass spectrometry (SPE-GC × GC–ToF-MS). On average, 94 % speciation of total measured NMVOC emissions was achieved across all fuel types. The largest contributors to emissions from most fuel types were small non-aromatic oxygenated species, phenolics and furanics. The emission factors (in g kg−1) for total gas-phase NMVOCs were fuelwood (18.7, 4.3–96.7), cow dung cake (62.0, 35.3–83.0), crop residue (37.9, 8.9–73.8), charcoal (5.4, 2.4–7.9), sawdust (72.4, 28.6–115.5), municipal solid waste (87.3, 56.6–119.1) and liquefied petroleum gas (5.7, 1.9–9.8). The emission factors measured in this study allow for better characterisation, evaluation and understanding of the air quality impacts of residential solid-fuel combustion in India.
- Published
- 2021
22. Emissions of intermediate-volatility and semi-volatile organic compounds from domestic fuels used in Delhi, India
- Author
-
Stewart, Gareth, Nelson, Beth S., Acton, W. Joe F., Vaughan, Adam Robert, Farren, Naomi J., Hopkins, James R., Ward, Martyn W., Swift, Stefan J., Arya, Rahul, Mondal, Arnab, Jangirh, Ritu, Ahlawat, Sakshi, Yadav, Lokesh, Sharma, Sudhir K., Yunus, Siti S. M., Hewitt, C N, Nemitz, Eiko, Mullinger, Neil, Gadi, Ranu, Sahu, Lokesh K., Tripathi, Nidhi, Rickard, Andrew R., Lee, James D., Mandal, Tuhin K., Hamilton, Jacqueline F., Stewart, Gareth, Nelson, Beth S., Acton, W. Joe F., Vaughan, Adam Robert, Farren, Naomi J., Hopkins, James R., Ward, Martyn W., Swift, Stefan J., Arya, Rahul, Mondal, Arnab, Jangirh, Ritu, Ahlawat, Sakshi, Yadav, Lokesh, Sharma, Sudhir K., Yunus, Siti S. M., Hewitt, C N, Nemitz, Eiko, Mullinger, Neil, Gadi, Ranu, Sahu, Lokesh K., Tripathi, Nidhi, Rickard, Andrew R., Lee, James D., Mandal, Tuhin K., and Hamilton, Jacqueline F.
- Abstract
Biomass burning emits significant quantities of intermediate-volatility and semi-volatile volatile organic compounds (I/SVOCs) in a complex mixture, probably containing many thousands of chemical species. These components are significantly more toxic and have poorly understood chemistry compared to volatile organic compounds routinely analysed in ambient air, however quantification of I/SVOCs presents a difficult analytical challenge. The gases and particles emitted during the test combustion of a range of domestic solid fuels collected from across New Delhi were sampled and analysed. Organic aerosol was collected onto Teflon (PTFE) filters and residual low-volatility gases were adsorbed to the surface of solid-phase extraction (SPE) disks. A new method relying on accelerated solvent extraction (ASE) coupled to comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry (GC×GC-ToF-MS) was developed. This highly sensitive and powerful analytical technique enabled over 3000 peaks from I/SVOC species with unique mass spectra to be detected. 15–100 % of gas-phase emissions and 7–100 % of particle-phase emissions were characterised. The method was analysed for suitability to make quantitative measurements of I/SVOCs using SPE disks. Analysis of SPE disks indicated phenolic and furanic compounds were important to gas-phase I/SVOC emissions and levoglucosan to the aerosol phase. Gas- and particle-phase emission factors for 21 polycyclic aromatic hydrocarbons (PAHs) were derived, including 16 compounds listed by the US EPA as priority pollutants. Gas-phase emissions were dominated by smaller PAHs. New emission factors were measured (mg kg−1) for PAHs from combustion of cow dung cake (615), municipal solid waste (1022), crop residue (747), sawdust (1236), fuel wood (247), charcoal (151) and liquified petroleum gas (56). The results of this study indicate that cow dung cake and municipal solid waste burning are likely to be significant PAH sources a
- Published
- 2021
23. Observations of speciated isoprene nitrates in Beijing: implications for isoprene chemistry
- Author
-
Reeves, Claire E., primary, Mills, Graham P., additional, Whalley, Lisa K., additional, Acton, W. Joe F., additional, Bloss, William J., additional, Crilley, Leigh R., additional, Grimmond, Sue, additional, Heard, Dwayne E., additional, Hewitt, C. Nicholas, additional, Hopkins, James R., additional, Kotthaus, Simone, additional, Kramer, Louisa J., additional, Jones, Roderic L., additional, Lee, James D., additional, Liu, Yanhui, additional, Ouyang, Bin, additional, Slater, Eloise, additional, Squires, Freya, additional, Wang, Xinming, additional, Woodward-Massey, Robert, additional, and Ye, Chunxiang, additional
- Published
- 2021
- Full Text
- View/download PDF
24. Emissions of non-methane volatile organic compounds from combustion of domestic fuels in Delhi, India
- Author
-
Stewart, Gareth J., primary, Acton, W. Joe F., additional, Nelson, Beth S., additional, Vaughan, Adam R., additional, Hopkins, James R., additional, Arya, Rahul, additional, Mondal, Arnab, additional, Jangirh, Ritu, additional, Ahlawat, Sakshi, additional, Yadav, Lokesh, additional, Sharma, Sudhir K., additional, Dunmore, Rachel E., additional, Yunus, Siti S. M., additional, Hewitt, C. Nicholas, additional, Nemitz, Eiko, additional, Mullinger, Neil, additional, Gadi, Ranu, additional, Sahu, Lokesh K., additional, Tripathi, Nidhi, additional, Rickard, Andrew R., additional, Lee, James D., additional, Mandal, Tuhin K., additional, and Hamilton, Jacqueline F., additional
- Published
- 2021
- Full Text
- View/download PDF
25. Emissions of intermediate-volatility and semi-volatile organic compounds from domestic fuels used in Delhi, India
- Author
-
Stewart, Gareth J., primary, Nelson, Beth S., additional, Acton, W. Joe F., additional, Vaughan, Adam R., additional, Farren, Naomi J., additional, Hopkins, James R., additional, Ward, Martyn W., additional, Swift, Stefan J., additional, Arya, Rahul, additional, Mondal, Arnab, additional, Jangirh, Ritu, additional, Ahlawat, Sakshi, additional, Yadav, Lokesh, additional, Sharma, Sudhir K., additional, Yunus, Siti S. M., additional, Hewitt, C. Nicholas, additional, Nemitz, Eiko, additional, Mullinger, Neil, additional, Gadi, Ranu, additional, Sahu, Lokesh K., additional, Tripathi, Nidhi, additional, Rickard, Andrew R., additional, Lee, James D., additional, Mandal, Tuhin K., additional, and Hamilton, Jacqueline F., additional
- Published
- 2021
- Full Text
- View/download PDF
26. Low-NO atmospheric oxidation pathways in a polluted megacity
- Author
-
Newland, Mike J., primary, Bryant, Daniel J., additional, Dunmore, Rachel E., additional, Bannan, Thomas J., additional, Acton, W. Joe F., additional, Langford, Ben, additional, Hopkins, James R., additional, Squires, Freya A., additional, Dixon, William, additional, Drysdale, William S., additional, Ivatt, Peter D., additional, Evans, Mathew J., additional, Edwards, Peter M., additional, Whalley, Lisa K., additional, Heard, Dwayne E., additional, Slater, Eloise J., additional, Woodward-Massey, Robert, additional, Ye, Chunxiang, additional, Mehra, Archit, additional, Worrall, Stephen D., additional, Bacak, Asan, additional, Coe, Hugh, additional, Percival, Carl J., additional, Hewitt, C. Nicholas, additional, Lee, James D., additional, Cui, Tianqu, additional, Surratt, Jason D., additional, Wang, Xinming, additional, Lewis, Alastair C., additional, Rickard, Andrew R., additional, and Hamilton, Jacqueline F., additional
- Published
- 2021
- Full Text
- View/download PDF
27. Seasonal analysis of submicron aerosol in Old Delhi using high resolution aerosol mass spectrometry: Chemical characterisation, source apportionment and new marker identification
- Author
-
Cash, James M., Langford, Ben, Marco, Chiara, Mullinger, Neil, Allan, James, Reyes-Villegas, Ernesto, Joshi, Ruthambara, Heal, Mathew R., Acton, W. Joe F., Hewitt, Nick, Misztal, Pawel, Drysdale, Will, Mandal, Tuhin K., Shivani, Gadi, Ranu, and Nemitz, Eiko
- Subjects
aerosol mass spectrometry ,Source apportionment ,010504 meteorology & atmospheric sciences ,air pollution ,positive matrix factorization ,megacities ,Delhi ,PM composition ,01 natural sciences ,0105 earth and related environmental sciences - Abstract
We present the first real-time composition of submicron particulate matter (PM1) in Old Delhi using high resolution aerosol mass spectrometry (HR-AMS). Old Delhi is one of the most polluted locations in the world, and PM1 concentrations reached ~ 600 µg m−3 during the most polluted period, the post-monsoon, where PM1 increased by 178 % over the pre-monsoon period. Using positive matrix factorisation (PMF) to perform source apportionment analysis, two burning-related factors contribute the most (35 %) to the post-monsoon increase. The first PMF factor, semi-volatility biomass burning organic aerosol (SVBBOA), shows a high correlation with earth observation fire counts in surrounding states which links its origin to crop residue burning. The second is a solid-fuel OA (SFOA) factor with links to local open burning due to its high composition of polyaromatic hydrocarbons (PAH) and novel AMS measured marker species for polychlorinated dibenzodioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs). Two traffic factors were resolved, one hydrocarbon-like OA (HOA) factor and another nitrogen-rich HOA (NHOA) factor. The N compounds within NHOA were mainly nitrile species which have not previously been identified within AMS measurements. Their PAH composition suggests that NHOA is linked to diesel, and HOA to compressed natural gas and gasoline. These factors combined make the largest relative contribution to primary PM1 mass during the pre-monsoon and monsoon periods, while contributing the second highest in the post-monsoon. A cooking OA (COA) factor shows strong links to the secondary factor, semi-volatility oxygenated OA (SVOOA). Correlations with co-located volatile organic compound (VOC) measurements and AMS measured organic nitrogen oxides (OrgNO) suggest SVOOA is formed from aged COA. It is also found that a significant increase in chloride concentrations (488 %) from pre-monsoon to post-monsoon correlates well with SVBBOA and SFOA suggesting that crop residue burning and open waste burning are responsible. A reduction in traffic emissions would effectively reduce concentrations across most of the year. In order to reduce the post-monsoon peak, sources such as funeral pyres, solid waste burning and crop residue burning should be considered when developing new air quality policy.
- Published
- 2020
28. Evaluating the sensitivity of radical chemistry and ozone formation to ambient VOCs and NOx in Beijing
- Author
-
Whalley, Lisa, Slater, Eloise, Woodward-Massey, Robert, Ye, Chunxiang, Lee, James D., Squires, Freya, Hopkins, James R., Dunmore, Rachel E., Marvin David Shaw, Hamilton, Jacqueline F., Lewis, Alastair C., Mehra, Archit, Worrall, Stephen David, Bacak, Asan, Bannan, Thomas J., Coe, Hugh, Ouyang, Bin, Jones, Roderic L., Crilley, Leigh R., Kramer, Louisa J., Bloss, William J., Vu, Tuan, Kotthaus, Simone, Grimmond, Sue, Sun, Yele, Xu, Weiqi, Yue, Siyao, Ren, Lujie, Acton, W. Joe F., Hewitt, C. N., Wang, Xinming, Fu, Pingqing, and Heard, Dwayne E.
- Abstract
Measurements of OH, HO2, RO2-complex (alkene and aromatic-related RO2) and total RO2 radicals taken during the AIRPRO campaign in central Beijing in the summer of 2017, alongside observations of OH reactivity are presented. The concentrations of radicals were elevated with OH reaching up to 2.8 × 107 molecule cm−3, HO2 peaked at 1 × 109 molecule cm−3 and the total RO2 concentration reached 5.5 × 109 molecule cm−3. OH reactivity (k(OH)) peaked at 89 s−1 during the night, with a minimum during the afternoons of ~ 22 s−1 on average. An experimental budget analysis, in which the rates of production and destruction of the radicals are compared, highlighted that although the sources and sinks of OH were balanced under high NO concentrations, the OH sinks exceeded the known sources (by 15 ppbv hr−1) under the very low NO conditions (2 production rate exceeded the rate of destruction by ~ 50 ppbv hr−1, whilst the rate of destruction of total-RO2 exceeded the production by the same rate indicating that the net propagation rate of RO2 to HO2 may be substantially slower than assumed. If just 10 % of the RO2 radicals propagate to HO2 upon reaction with NO, the HO2 and RO2 budgets could be closed at high NO, but at low NO this lower RO2 to HO2 propagation rate revealed a missing RO2 sink that was similar in magnitude to the missing OH source. A detailed box model that incorporated the latest MCM chemical mechanism (MCM3.3.1) reproduced the observed OH concentrations well, but over-predicted the observed HO2 under low concentrations of NO (2 (both the complex-RO2 fraction and other RO2 types which we classify as simple-RO2) most significantly at the highest NO concentrations. The model also under-predicted the observed k(OH) consistently by ~ 10 s−1 across all NOx levels highlighting that the good agreement for OH was fortuitous due to a cancellation of missing OH source and sink terms in its budget. Including heterogeneous loss of HO2 to aerosol surfaces did reduce the modelled HO2 concentrations in-line with the observations, but only at NO mixing ratios 2 concentration on several mornings when the Cl atom concentration was calculated to exceed 1 × 104 atoms cm−3 and could reconcile the modelled and measured RO2 concentrations at these times. However, on other mornings, when the Cl atom concentration was lower, large under-predictions in total RO2 remained. Furthermore, the inclusion of Cl atom chemistry did not enhance the modelled RO2 beyond the first few hours after sunrise and so was unable to resolve the modelled under-prediction in RO2 observed at other times of the day. Model scenarios, in which missing VOC reactivity was included as an additional reaction that converted OH to RO2, highlighted that the modelled OH, HO2 and RO2 concentrations were sensitive to the choice of RO2 product. The level of modelled to measured agreement for HO2 and RO2 (both complex and simple) could be improved if the missing OH reactivity formed a larger RO2 species that was able to undergo reaction with NO, followed by isomerisation reactions reforming other RO2 species, before eventually generating HO2. In this work an α-pinene-derived RO2 species was used as an example. In this simulation, consistent with the experimental budget analysis, the model underestimated the observed OH indicating a missing OH source. The model uncertainty, with regards to the types of RO2 species present and the radicals they form upon reaction with NO (HO2 directly or another RO2 species), leads to over an order of magnitude less O3 production calculated from the predicted peroxy radicals than calculated from the observed peroxy radicals at the highest NO concentrations. This demonstrates the rate at which the larger RO2 species propagate to HO2 or to another RO2 or indeed to OH needs to be understood to accurately simulate the rate of ozone production in environments such as Beijing where large multifunctional VOCs are likely present.
- Published
- 2020
29. PM1 composition and source apportionment at two sites in Delhi, India across multiple seasons
- Author
-
Reyes Villegas, Ernesto, Panda, Upasana, Darbyshire, Eoghan, Cash, James M, Joshi, Rutambhara, Langford, Ben, Di Marco, Chiara F, Mullinger, Neil, Acton, W Joe F, Drysdale, Will, Nemitz, Eiko, Flynn, Michael, Voliotis, Aristeidis, McFiggans, Gordon, Coe, Hugh, Lee, James, Hewitt, C Nicholas, Heal, Mathew R, Gunthe, Sachin S, Shivani, Gadi, Ranu, Singh, Siddhartha, Soni, Vijay, and Allan, James
- Abstract
Air pollution in urban environments has been shown to have a negative impact on air quality and human health, particularly in megacities. Over recent decades, Delhi, India has suffered high atmospheric pollution, with significant particulate matter (PM) concentrations as result of anthropogenic activities. Organic aerosols (OA) are composed of thousands of different chemical species and are one of the main constituents of submicron particles. However, quantitative knowledge of OA composition, their sources and processes in urban environments is still limited. This is important particularly in India, as Delhi is a massive, inhomogeneous conurbation, which we would expect that the apportionment and concentrations will vary depending on where in Delhi the measurements/source apportionment is performed, indicating the need of multi-site measurements. This study presents the first multisite analysis carried out in India over different seasons, with a focus on identifying OA sources. The measurements were taken during 2018 at two sites in Delhi, India. One site was located at the India Meteorological Department, New Delhi (ND). The other site was located at the Indira Gandhi Delhi Technical University for Women, Old Delhi (OD). Non-refractory submicron aerosol (NR-PM1) concentrations (ammonium, nitrate, sulphate, chloride and organic aerosols) of four aerosol mass spectrometers were analysed. Collocated measurements of VOC, black carbon, NOx and CO were performed. Positive matrix factorization (PMF) analysis was performed to separate the organic fraction, identifying a number of conventional factors: hydrocarbon-like OA (HOA) related to traffic emissions, biomass burning OA (BBOA), cooking OA (COA) and secondary OA (SOA). A composition-based estimate of PM1 is defined by combining BC and NR-PM1 (C-PM1 = BC + NR-PM1). No significant difference was observed on C-PM1 concentrations between sites; OD (142 ± 117 µg m−3) compared to ND (123 ± 71 µg m−3), from post-monsoon measurements. A wider variability was observed between seasons, where pre-monsoon and monsoon showed C-PM1 concentrations lower than 60 µg m−3. A seasonal variation in C-PM1 composition was observed; SO42− showed a high contribution over pre-monsoon and monsoon seasons while NO3− and Cl− had a higher contribution in winter and post-monsoon. The main primary aerosol source was from traffic, which is consistent with the PMF analysis and aethalometer model analysis. Thus, in order to reduce PM1 concentrations in Delhi through local emission controls traffic emissions control offers the greatest opportunity. PMF-AMS mass spectra will help to improve future aerosol source apportionment studies. The information generated in this study increases our understanding of PM1 composition and OA sources in Delhi, India. Furthermore, the scientific findings provide significant information to strengthen legislation that aims to improve air quality in India.
- Published
- 2020
30. Elevated levels of OH observed in haze events during wintertime in central Beijing
- Author
-
Slater, Eloise, Whalley, Lisa K., Woodward-Massey, Robert, Ye, Chunxiang, Lee, James D., Squires, Freja, Hopkins, James R., Dunmore, Rachel E., Shaw, Marvin, Hamilton, Jacqueline F., Lewis, Alastair C., Crilley, Leigh R., Kramer, Louisa J., Bloss, William J., Vu, Tuan, Sun, Yele, Xu, Weiqi, Yue, Siyao, Ren, Lujie, Acton, W. Joe F., Hewitt, C N, Wang, Xinming, Fu, Pingqing, Heard, Dwayne E., Slater, Eloise, Whalley, Lisa K., Woodward-Massey, Robert, Ye, Chunxiang, Lee, James D., Squires, Freja, Hopkins, James R., Dunmore, Rachel E., Shaw, Marvin, Hamilton, Jacqueline F., Lewis, Alastair C., Crilley, Leigh R., Kramer, Louisa J., Bloss, William J., Vu, Tuan, Sun, Yele, Xu, Weiqi, Yue, Siyao, Ren, Lujie, Acton, W. Joe F., Hewitt, C N, Wang, Xinming, Fu, Pingqing, and Heard, Dwayne E.
- Abstract
Wintertime in situ measurements of OH, HO2 and RO2 radicals and OH reactivity were made in central Beijing during November and December 2016. Exceptionally elevated NO was observed on occasions, up to ∼250 ppbv. The daily maximum mixing ratios for radical species varied significantly day-to-day over the ranges 1–8×106 cm−3 (OH), 0.2–1.5×108 cm−3 (HO2) and 0.3–2.5×108 cm−3 (RO2). Averaged over the full observation period, the mean daytime peak in radicals was 2.7×106, 0.39×108 and 0.88×108 cm−3 for OH, HO2 and total RO2, respectively. The main daytime source of new radicals via initiation processes (primary production) was the photolysis of HONO (∼83 %), and the dominant termination pathways were the reactions of OH with NO and NO2, particularly under polluted haze conditions. The Master Chemical Mechanism (MCM) v3.3.1 operating within a box model was used to simulate the concentrations of OH, HO2 and RO2. The model underpredicted OH, HO2 and RO2, especially when NO mixing ratios were high (above 6 ppbv). The observation-to-model ratio of OH, HO2 and RO2 increased from ∼1 (for all radicals) at 3 ppbv of NO to a factor of ∼3, ∼20 and ∼91 for OH, HO2 and RO2, respectively, at ∼200 ppbv of NO. The significant underprediction of radical concentrations by the MCM suggests a deficiency in the representation of gas-phase chemistry at high NOx. The OH concentrations were surprisingly similar (within 20 % during the day) in and outside of haze events, despite j(O1D) decreasing by 50 % during haze periods. These observations provide strong evidence that gas-phase oxidation by OH can continue to generate secondary pollutants even under high-pollution episodes, despite the reduction in photolysis rates within haze.
- Published
- 2020
31. Vertical profiles of biogenic volatile organic compounds as observed online at a tower in Beijing
- Author
-
Zhang, Huina, Zhang, Yanli, Huang, Zhonghui, Acton, W. Joe F., Wang, Zhaoyi, Nemitz, Eiko, Langford, Ben, Mullinger, Neil, Davison, Brian, Shi, Zongbo, Liu, Di, Song, Wei, Yang, Weiqiang, Zeng, Jianqiang, Wu, Zhenfeng, Fu, Pingqing, Zhang, Qiang, Wang, Xinming, Zhang, Huina, Zhang, Yanli, Huang, Zhonghui, Acton, W. Joe F., Wang, Zhaoyi, Nemitz, Eiko, Langford, Ben, Mullinger, Neil, Davison, Brian, Shi, Zongbo, Liu, Di, Song, Wei, Yang, Weiqiang, Zeng, Jianqiang, Wu, Zhenfeng, Fu, Pingqing, Zhang, Qiang, and Wang, Xinming
- Abstract
Vertical profiles of isoprene and monoterpenes were measured by a proton transfer reaction-time of flight-mass spectrometry (PTR-ToF-MS) at heights of 3, 15, 32, 64, and 102 m above the ground on the Institute of Atmospheric Physics (IAP) tower in central Beijing during the winter of 2016 and the summer of 2017. Isoprene mixing ratios were larger in summer due to much stronger local emissions whereas monoterpenes were lower in summer due largely to their consumption by much higher levels of ozone. Isoprene mixing ratios were the highest at the 32 m in summer (1.64 ± 0.66 ppbV) and at 15 m in winter (1.41 ± 0.64 ppbV) with decreasing concentrations to the ground and to the 102 m, indicating emission from the tree canopy of the surrounding parks. Monoterpene mixing ratios were the highest at the 3 m height in both the winter (0.71 ± 0.42 ppbV) and summer (0.16 ± 0.10 ppbV) with a gradual decreasing trend to 102 m, indicting an emission from near the ground level. The lowest isoprene and monoterpene mixing ratios all occurred at 102 m, which were 0.71 ± 0.42 ppbV (winter) and 1.35 ± 0.51 ppbV (summer) for isoprene, and 0.42 ± 0.22 ppbV (winter) and 0.07 ± 0.06 ppbV (summer) for monoterpenes. Isoprene in the summer and monoterpenes in the winter, as observed at the five heights, showed significant mutual correlations. In the winter monoterpenes were positively correlated with combustion tracers CO and acetonitrile at 3 m, suggesting possible anthropogenic sources.
- Published
- 2020
32. Measurements of traffic-dominated pollutant emissions in a Chinese megacity
- Author
-
Squires, Freya A., Nemitz, Eiko, Langford, Ben, Wild, Oliver, Drysdale, Will S., Acton, W. Joe F., Fu, Pingqing, Grimmond, C. Sue B., Hamilton, Jacqueline F., Hewitt, C. Nicholas, Hollaway, Michael, Kotthaus, Simone, Lee, James, Metzger, Stefan, Pingintha-Durden, Natchaya, Shaw, Marvin, Vaughan, Adam R., Wang, Xinming, Wu, Ruili, Zhang, Qiang, Zhang, Yanli, Squires, Freya A., Nemitz, Eiko, Langford, Ben, Wild, Oliver, Drysdale, Will S., Acton, W. Joe F., Fu, Pingqing, Grimmond, C. Sue B., Hamilton, Jacqueline F., Hewitt, C. Nicholas, Hollaway, Michael, Kotthaus, Simone, Lee, James, Metzger, Stefan, Pingintha-Durden, Natchaya, Shaw, Marvin, Vaughan, Adam R., Wang, Xinming, Wu, Ruili, Zhang, Qiang, and Zhang, Yanli
- Abstract
Direct measurements of NOx, CO and aromatic volatile organic compound (VOC) (benzene, toluene, C2-benzenes and C3-benzenes) flux were made for a central area of Beijing using the eddy-covariance technique. Measurements were made during two intensive field campaigns in central Beijing as part of the Air Pollution and Human Health (APHH) project, the first in November–December 2016 and the second during May–June 2017, to contrast wintertime and summertime emission rates. There was little difference in the magnitude of NOx flux between the two seasons (mean NOx flux was 4.41 mg m−2 h−1 in the winter compared to 3.55 mg m−2 h−1 in the summer). CO showed greater seasonal variation, with mean CO flux in the winter campaign (34.7 mg m−2 h−1) being over twice that of the summer campaign (15.2 mg m−2 h−1). Larger emissions of aromatic VOCs in summer were attributed to increased evaporation due to higher temperatures. The largest fluxes in NOx and CO generally occurred during the morning and evening rush hour periods, indicating a major traffic source with high midday emissions of CO, indicating an additional influence from cooking fuel. Measured NOx and CO fluxes were then compared to the MEIC 2013 emissions inventory, which was found to significantly overestimate emissions for this region, providing evidence that proxy-based emissions inventories have positive biases in urban centres. This first set of pollutant fluxes measured in Beijing provides an important benchmark of emissions from the city which can help to inform and evaluate current emissions inventories.
- Published
- 2020
33. Surface–atmosphere fluxes of volatile organic compounds in Beijing
- Author
-
Acton, W. Joe F., Huang, Zhonghui, Davison, Brian, Drysdale, Will S., Fu, Pingqing, Hollaway, Michael, Langford, Ben, Lee, James, Liu, Yanhui, Metzger, Stefan, Mullinger, Neil, Nemitz, Eiko, Reeves, Claire E., Squires, Freya A., Vaughan, Adam R., Wang, Xinming, Wang, Zhaoyi, Wild, Oliver, Zhang, Qiang, Zhang, Yanli, Hewitt, C. Nicholas, Acton, W. Joe F., Huang, Zhonghui, Davison, Brian, Drysdale, Will S., Fu, Pingqing, Hollaway, Michael, Langford, Ben, Lee, James, Liu, Yanhui, Metzger, Stefan, Mullinger, Neil, Nemitz, Eiko, Reeves, Claire E., Squires, Freya A., Vaughan, Adam R., Wang, Xinming, Wang, Zhaoyi, Wild, Oliver, Zhang, Qiang, Zhang, Yanli, and Hewitt, C. Nicholas
- Abstract
Mixing ratios of volatile organic compounds (VOCs) were recorded in two field campaigns in central Beijing as part of the Air Pollution and Human Health in a Chinese Megacity (APHH) project. These data were used to calculate, for the first time in Beijing, the surface–atmosphere fluxes of VOCs using eddy covariance, giving a top-down estimation of VOC emissions from a central area of the city. The results were then used to evaluate the accuracy of the Multi-resolution Emission Inventory for China (MEIC). The APHH winter and summer campaigns took place in November and December 2016 and May and June 2017, respectively. The largest VOC fluxes observed were of small oxygenated compounds such as methanol, ethanol + formic acid and acetaldehyde, with average emission rates of 8.31 ± 8.5, 3.97 ± 3.9 and 1.83 ± 2.0 nmol m−2 s−1, respectively, in the summer. A large flux of isoprene was observed in the summer, with an average emission rate of 5.31 ± 7.7 nmol m−2 s−1. While oxygenated VOCs made up 60 % of the molar VOC flux measured, when fluxes were scaled by ozone formation potential and peroxyacyl nitrate (PAN) formation potential the high reactivity of isoprene and monoterpenes meant that these species represented 30 % and 28 % of the flux contribution to ozone and PAN formation potential, respectively. Comparison of measured fluxes with the emission inventory showed that the inventory failed to capture the magnitude of VOC emissions at the local scale.
- Published
- 2020
34. Rainforest-like Atmospheric Chemistry in a Polluted Megacity
- Author
-
Newland, Mike J., Bryant, Daniel J., Dunmore, Rachel, Bannan, Thomas J., Acton, W. Joe F., Langford, Ben, Hopkins, James R., Squires, Freya A., Dixon, William, Drysdale, William S., Ivatt, Peter D., Evans, Mathew J., Edwards, Peter M., Whalley, Lisa K., Heard, Dwayne E., Slater, Eloise, Woodward-Massey, Robert, Ye, Chunxiang, Mehra, Archit, Worrall, Stephen David, Bacak, Asan, Coe, Hugh, Percival, Carl J., Hewitt, C N, Lee, James D., Cui, Tianqu, Surratt, Jason D., Wang, Xinming, Lewis, Alastair C., Rickard, Andrew, Hamilton, Jacqueline F., Newland, Mike J., Bryant, Daniel J., Dunmore, Rachel, Bannan, Thomas J., Acton, W. Joe F., Langford, Ben, Hopkins, James R., Squires, Freya A., Dixon, William, Drysdale, William S., Ivatt, Peter D., Evans, Mathew J., Edwards, Peter M., Whalley, Lisa K., Heard, Dwayne E., Slater, Eloise, Woodward-Massey, Robert, Ye, Chunxiang, Mehra, Archit, Worrall, Stephen David, Bacak, Asan, Coe, Hugh, Percival, Carl J., Hewitt, C N, Lee, James D., Cui, Tianqu, Surratt, Jason D., Wang, Xinming, Lewis, Alastair C., Rickard, Andrew, and Hamilton, Jacqueline F.
- Published
- 2020
35. Comprehensive organic emission profiles, secondary organic aerosol production potential, and OH reactivity of domestic fuel combustion in Delhi, India
- Author
-
Stewart, Gareth J., primary, Nelson, Beth S., additional, Acton, W. Joe F., additional, Vaughan, Adam R., additional, Hopkins, James R., additional, Yunus, Siti S. M., additional, Hewitt, C. Nicholas, additional, Nemitz, Eiko, additional, Mandal, Tuhin K., additional, Gadi, Ranu, additional, Sahu, Lokesh. K., additional, Rickard, Andrew R., additional, Lee, James D., additional, and Hamilton, Jacqueline F., additional
- Published
- 2021
- Full Text
- View/download PDF
36. Using highly time-resolved online mass spectrometry to examine biogenic and anthropogenic contributions to organic aerosol in Beijing
- Author
-
Mehra, Archit, primary, Canagaratna, Manjula, additional, Bannan, Thomas J., additional, Worrall, Stephen D., additional, Bacak, Asan, additional, Priestley, Michael, additional, Liu, Dantong, additional, Zhao, Jian, additional, Xu, Weiqi, additional, Sun, Yele, additional, Hamilton, Jacqueline F., additional, Squires, Freya A., additional, Lee, James, additional, Bryant, Daniel J., additional, Hopkins, James R., additional, Elzein, Atallah, additional, Budisulistiorini, Sri Hapsari, additional, Cheng, Xi, additional, Chen, Qi, additional, Wang, Yuwei, additional, Wang, Lin, additional, Stark, Harald, additional, Krechmer, Jordan E., additional, Brean, James, additional, Slater, Eloise, additional, Whalley, Lisa, additional, Heard, Dwayne, additional, Ouyang, Bin, additional, Acton, W. Joe F., additional, Hewitt, C. Nicholas, additional, Wang, Xinming, additional, Fu, Pingqing, additional, Jayne, John, additional, Worsnop, Douglas, additional, Allan, James, additional, Percival, Carl, additional, and Coe, Hugh, additional
- Published
- 2021
- Full Text
- View/download PDF
37. Avoiding high ozone pollution in Delhi, India
- Author
-
Chen, Ying, primary, Beig, Gufran, additional, Archer-Nicholls, Scott, additional, Drysdale, Will, additional, Acton, W. Joe F., additional, Lowe, Douglas, additional, Nelson, Beth, additional, Lee, James, additional, Ran, Liang, additional, Wang, Yu, additional, Wu, Zhijun, additional, Sahu, Saroj Kumar, additional, Sokhi, Ranjeet S., additional, Singh, Vikas, additional, Gadi, Ranu, additional, Nicholas Hewitt, C., additional, Nemitz, Eiko, additional, Archibald, Alex, additional, McFiggans, Gordon, additional, and Wild, Oliver, additional
- Published
- 2021
- Full Text
- View/download PDF
38. Surface–atmosphere fluxes of volatile organic compounds in Beijing
- Author
-
Acton, W. Joe F., primary, Huang, Zhonghui, additional, Davison, Brian, additional, Drysdale, Will S., additional, Fu, Pingqing, additional, Hollaway, Michael, additional, Langford, Ben, additional, Lee, James, additional, Liu, Yanhui, additional, Metzger, Stefan, additional, Mullinger, Neil, additional, Nemitz, Eiko, additional, Reeves, Claire E., additional, Squires, Freya A., additional, Vaughan, Adam R., additional, Wang, Xinming, additional, Wang, Zhaoyi, additional, Wild, Oliver, additional, Zhang, Qiang, additional, Zhang, Yanli, additional, and Hewitt, C. Nicholas, additional
- Published
- 2020
- Full Text
- View/download PDF
39. Elevated levels of OH observed in haze events during wintertime in central Beijing
- Author
-
Slater, Eloise J., primary, Whalley, Lisa K., additional, Woodward-Massey, Robert, additional, Ye, Chunxiang, additional, Lee, James D., additional, Squires, Freya, additional, Hopkins, James R., additional, Dunmore, Rachel E., additional, Shaw, Marvin, additional, Hamilton, Jacqueline F., additional, Lewis, Alastair C., additional, Crilley, Leigh R., additional, Kramer, Louisa, additional, Bloss, William, additional, Vu, Tuan, additional, Sun, Yele, additional, Xu, Weiqi, additional, Yue, Siyao, additional, Ren, Lujie, additional, Acton, W. Joe F., additional, Hewitt, C. Nicholas, additional, Wang, Xinming, additional, Fu, Pingqing, additional, and Heard, Dwayne E., additional
- Published
- 2020
- Full Text
- View/download PDF
40. Supplementary material to "Emissions of non-methane volatile organic compounds from combustion of domestic fuels in Delhi, India"
- Author
-
Stewart, Gareth J., primary, Acton, W. Joe F., additional, Nelson, Beth S., additional, Vaughan, Adam R., additional, Hopkins, James R., additional, Arya, Rahul, additional, Mondal, Arnab, additional, Jangirh, Ritu, additional, Ahlawat, Sakshi, additional, Yadav, Lokesh, additional, Sharma, Sudhir K., additional, Dunmore, Rachel E., additional, Yunus, Siti S. M., additional, Hewitt, C. Nicholas, additional, Nemitz, Eiko, additional, Mullinger, Neil, additional, Gadi, Ranu, additional, Sahu, Lokesh K., additional, Tripathi, Nidhi, additional, Rickard, Andrew R., additional, Lee, James D., additional, Mandal, Tuhin K., additional, and Hamilton, Jacqueline F., additional
- Published
- 2020
- Full Text
- View/download PDF
41. Emissions of non-methane volatile organic compounds from combustion of domestic fuels in Delhi, India
- Author
-
Stewart, Gareth J., primary, Acton, W. Joe F., additional, Nelson, Beth S., additional, Vaughan, Adam R., additional, Hopkins, James R., additional, Arya, Rahul, additional, Mondal, Arnab, additional, Jangirh, Ritu, additional, Ahlawat, Sakshi, additional, Yadav, Lokesh, additional, Sharma, Sudhir K., additional, Dunmore, Rachel E., additional, Yunus, Siti S. M., additional, Hewitt, C. Nicholas, additional, Nemitz, Eiko, additional, Mullinger, Neil, additional, Gadi, Ranu, additional, Sahu, Lokesh K., additional, Tripathi, Nidhi, additional, Rickard, Andrew R., additional, Lee, James D., additional, Mandal, Tuhin K., additional, and Hamilton, Jacqueline F., additional
- Published
- 2020
- Full Text
- View/download PDF
42. Evaluating the sensitivity of radical chemistry and ozone formation to ambient VOCs and NOx in Beijing
- Author
-
Whalley, Lisa K., primary, Slater, Eloise J., additional, Woodward-Massey, Robert, additional, Ye, Chunxiang, additional, Lee, James D., additional, Squires, Freya, additional, Hopkins, James R., additional, Dunmore, Rachel E., additional, Shaw, Marvin, additional, Hamilton, Jacqueline F., additional, Lewis, Alastair C., additional, Mehra, Archit, additional, Worrall, Stephen D., additional, Bacak, Asan, additional, Bannan, Thomas J., additional, Coe, Hugh, additional, Ouyang, Bin, additional, Jones, Roderic L., additional, Crilley, Leigh R., additional, Kramer, Louisa J., additional, Bloss, William J., additional, Vu, Tuan, additional, Kotthaus, Simone, additional, Grimmond, Sue, additional, Sun, Yele, additional, Xu, Weiqi, additional, Yue, Siyao, additional, Ren, Lujie, additional, Acton, W. Joe F., additional, Hewitt, C. Nicholas, additional, Wang, Xinming, additional, Fu, Pingqing, additional, and Heard, Dwayne E., additional
- Published
- 2020
- Full Text
- View/download PDF
43. Vertical profiles of biogenic volatile organic compounds as observed online at a tower in Beijing
- Author
-
Zhang, Huina, primary, Zhang, Yanli, additional, Huang, Zhonghui, additional, Acton, W. Joe F., additional, Wang, Zhaoyi, additional, Nemitz, Eiko, additional, Langford, Ben, additional, Mullinger, Neil, additional, Davison, Brian, additional, Shi, Zongbo, additional, Liu, Di, additional, Song, Wei, additional, Yang, Weiqiang, additional, Zeng, Jianqiang, additional, Wu, Zhenfeng, additional, Fu, Pingqing, additional, Zhang, Qiang, additional, and Wang, Xinming, additional
- Published
- 2020
- Full Text
- View/download PDF
44. Emissions of intermediate-volatility and semi-volatile organic compounds from domestic fuels used in Delhi, India
- Author
-
Stewart, Gareth J., primary, Nelson, Beth S., additional, Acton, W. Joe F., additional, Vaughan, Adam R., additional, Farren, Naomi J., additional, Hopkins, James R., additional, Ward, Martyn W., additional, Swift, Stefan J., additional, Arya, Rahul, additional, Mondal, Arnab, additional, Jangirh, Ritu, additional, Ahlawat, Sakshi, additional, Yadav, Lokesh, additional, Sharma, Sudhir K., additional, Yunus, Siti S. M., additional, Hewitt, C. Nicholas, additional, Nemitz, Eiko, additional, Mullinger, Neil, additional, Gadi, Ranu, additional, Sahu, Lokesh K., additional, Tripathi, Nidhi, additional, Rickard, Andrew R., additional, Lee, James D., additional, Mandal, Tuhin K., additional, and Hamilton, Jacqueline F., additional
- Published
- 2020
- Full Text
- View/download PDF
45. Supplementary material to "Emissions of intermediate-volatility and semi-volatile organic compounds from domestic fuels used in Delhi, India"
- Author
-
Stewart, Gareth J., primary, Nelson, Beth S., additional, Acton, W. Joe F., additional, Vaughan, Adam R., additional, Farren, Naomi J., additional, Hopkins, James R., additional, Ward, Martyn W., additional, Swift, Stefan J., additional, Arya, Rahul, additional, Mondal, Arnab, additional, Jangirh, Ritu, additional, Ahlawat, Sakshi, additional, Yadav, Lokesh, additional, Sharma, Sudhir K., additional, Yunus, Siti S. M., additional, Hewitt, C. Nicholas, additional, Nemitz, Eiko, additional, Mullinger, Neil, additional, Gadi, Ranu, additional, Sahu, Lokesh K., additional, Tripathi, Nidhi, additional, Rickard, Andrew R., additional, Lee, James D., additional, Mandal, Tuhin K., additional, and Hamilton, Jacqueline F., additional
- Published
- 2020
- Full Text
- View/download PDF
46. Measurements of traffic-dominated pollutant emissions in a Chinese megacity
- Author
-
Squires, Freya A., primary, Nemitz, Eiko, additional, Langford, Ben, additional, Wild, Oliver, additional, Drysdale, Will S., additional, Acton, W. Joe F., additional, Fu, Pingqing, additional, Grimmond, C. Sue B., additional, Hamilton, Jacqueline F., additional, Hewitt, C. Nicholas, additional, Hollaway, Michael, additional, Kotthaus, Simone, additional, Lee, James, additional, Metzger, Stefan, additional, Pingintha-Durden, Natchaya, additional, Shaw, Marvin, additional, Vaughan, Adam R., additional, Wang, Xinming, additional, Wu, Ruili, additional, Zhang, Qiang, additional, and Zhang, Yanli, additional
- Published
- 2020
- Full Text
- View/download PDF
47. Supplementary material to "Elevated levels of OH observed in haze events during wintertime in central Beijing"
- Author
-
Slater, Eloise J., primary, Whalley, Lisa K., additional, Woodward-Massey, Robert, additional, Ye, Chunxiang, additional, Lee, James D., additional, Squires, Freja, additional, Hopkins, James R., additional, Dunmore, Rachel E., additional, Shaw, Marvin, additional, Hamilton, Jacqueline F., additional, Lewis, Alastair C., additional, Crilley, Leigh R., additional, Kramer, Louisa, additional, Bloss, William, additional, Vu, Tuan, additional, Sun, Yele, additional, Xu, Weiqi, additional, Yue, Siyao, additional, Ren, Lujie, additional, Acton, W. Joe F., additional, Hewitt, C. Nicholas, additional, Wang, Xinming, additional, Fu, Pingqing, additional, and Heard, Dwayne E., additional
- Published
- 2020
- Full Text
- View/download PDF
48. Supplementary material to "Surface–atmosphere fluxes of volatile organic compounds in Beijing"
- Author
-
Acton, W. Joe F., primary, Huang, Zhonghui, additional, Davison, Brian, additional, Drysdale, Will S., additional, Fu, Pingqing, additional, Hollaway, Michael, additional, Langford, Ben, additional, Lee, James, additional, Liu, Yanhui, additional, Metzger, Stefan, additional, Mullinger, Neil, additional, Nemitz, Eiko, additional, Reeves, Claire E., additional, Squires, Freya A., additional, Vaughan, Adam R., additional, Wang, Xinming, additional, Wang, Zhaoyi, additional, Wild, Oliver, additional, Zhang, Qiang, additional, Zhang, Yanli, additional, and Hewitt, C. Nicholas, additional
- Published
- 2020
- Full Text
- View/download PDF
49. Rainforest-like Atmospheric Chemistry in a Polluted Megacity
- Author
-
Newland, Mike J., primary, Bryant, Daniel J., additional, Dunmore, Rachel E., additional, Bannan, Thomas J., additional, Acton, W. Joe F., additional, Langford, Ben, additional, Hopkins, James R., additional, Squires, Freya A., additional, Dixon, William, additional, Drysdale, William S., additional, Ivatt, Peter D., additional, Evans, Mathew J., additional, Edwards, Peter M., additional, Whalley, Lisa K., additional, Heard, Dwayne E., additional, Slater, Eloise J., additional, Woodward-Massey, Robert, additional, Ye, Chunxiang, additional, Mehra, Archit, additional, Worrall, Stephen D., additional, Bacak, Asan, additional, Coe, Hugh, additional, Percival, Carl J., additional, Hewitt, C. Nicholas, additional, Lee, James D., additional, Cui, Tianqu, additional, Surratt, Jason D., additional, Wang, Xinming, additional, Lewis, Alastair C., additional, Rickard, Andrew R., additional, and Hamilton, Jacqueline F., additional
- Published
- 2020
- Full Text
- View/download PDF
50. Supplementary material to "Rainforest-like Atmospheric Chemistry in a Polluted Megacity"
- Author
-
Newland, Mike J., primary, Bryant, Daniel J., additional, Dunmore, Rachel E., additional, Bannan, Thomas J., additional, Acton, W. Joe F., additional, Langford, Ben, additional, Hopkins, James R., additional, Squires, Freya A., additional, Dixon, William, additional, Drysdale, William S., additional, Ivatt, Peter D., additional, Evans, Mathew J., additional, Edwards, Peter M., additional, Whalley, Lisa K., additional, Heard, Dwayne E., additional, Slater, Eloise J., additional, Woodward-Massey, Robert, additional, Ye, Chunxiang, additional, Mehra, Archit, additional, Worrall, Stephen D., additional, Bacak, Asan, additional, Coe, Hugh, additional, Percival, Carl J., additional, Hewitt, C. Nicholas, additional, Lee, James D., additional, Cui, Tianqu, additional, Surratt, Jason D., additional, Wang, Xinming, additional, Lewis, Alastair C., additional, Rickard, Andrew R., additional, and Hamilton, Jacqueline F., additional
- Published
- 2020
- Full Text
- View/download PDF
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.