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Energy-efficient urban development leads to the compact design of apartments. Recirculating ventilation solutions are an attempt to minimize the space required for ventilation ducting, but more data on their performance are needed. Cooking is a major source of volatile organic compounds (VOCs) emissions. It is necessary to assess how well recirculating kitchen hoods perform in reducing the residents' exposure to cooking fumes compared to extracting hoods, and what airflow rates assure good removal efficiency. We have monitored the occupant exposure to several VOCs generated during the cooking of a model meal under different ventilation scenarios in a purpose-built test kitchen resembling the layout of a modern, open-space apartment. Time-resolved VOC emission profiles were measured using a proton transfer reaction time-of-flight mass spectrometer. The performance of activated carbon sorption-based filters for recirculating kitchen hoods in the removal of selected VOCs was also assessed. Alcohols, particularly ethanol, dominated emissions from cooking a typical Norwegian meal, but they also included acetaldehyde, acetone, carboxylic acids, and trimethylamine, among others. The use of recirculating kitchen hoods led to, on average, higher occupant exposure to VOCs compared to extracting kitchen hoods during and after cooking. This was in part due to the poor ethanol removal efficiency of the recirculating ventilation's air filters. [Display omitted] • PTR-ToF-MS used to monitor occupant's exposure to VOCs emitted during cooking. • Different kitchen ventilation conditions and configurations were tested. • Extracting kitchen ventilation outperforms recirculating solutions in VOCs removal. • VOCs emission from typical Norwegian cooking is dominated by ethanol. • Activated carbon filters have poor removal efficiency for ethanol. [ABSTRACT FROM AUTHOR]

Highlights • Amine emissions were monitored in real time with a PTR-MS instrument. • The PTR-MS analyzer was operated with ammonia as the source gas (NH 3 mode). • The instrument is suitable for an industrial application (compact, easy-to-use, low maintenance). Abstract We herein report on the adaptation and deployment of a compact and easy-to-use mass spectrometer for online monitoring of amines in industrial flue gas at ppb to ppm levels. The use of ammonia as a source gas in proton-transfer-reaction mass spectrometry (PTR-MS) greatly simplifies the detection of amines, making it possible to use a low-end commercial instrument version (PTR-QMS 300) for the measurements. We characterized the analytical performance of the instrument (sensitivity, limit of detection, precision, matrix effects) for nine solvent amines (monoethanolamine, dimethylaminoethanol, aminomethylpropanol, methyldiethanolamine, diglycolamine, piperazine, aminoethylpiperazine, methylpiperazine, N-(2-hydroxyethyl)piperazine) and three degradation amines (methylamine, dimethylamine, trimethylamine). The new analyzer was tested and validated in side-by-side measurements with established emission monitoring techniques at the Technology Centre Mongstad (TCM) in Norway. After validation, the instrument was permanently installed on top of the absorber tower to deliver real-time amine emission data to the plant information management system. [ABSTRACT FROM AUTHOR]

A PTR-QiTOF instrument was deployed in the field in the vicinity of the CO 2 Technology Center Mongstad (TCM) for measuring amines in ambient air. The observed single-to-double-digit pptv levels of dimethylamine (DMA) and trimethylamine (TMA) are comparable to natural background values reported in the literature for these species. No indication was found that these small alkylamines stem from industrial activities at Mongstad. Monoethanolamine (MEA) was observed at single-digit pptv levels, but further analytical work is needed to validate measurements at such low concentrations. No indication was found that small enhancements in ambient MEA levels were caused by emissions from TCM. No other industrial amines (2-amino-2-methylpropanol, diethylamine and piperazine) were detected in ambient air. According to the current state of knowledge, the observed levels of amines pose no harm to human health or the environment. [ABSTRACT FROM AUTHOR]

Laboratory experiments were carried out to study Schiff-base condensation reactions between amines and formaldehyde that occur on inlet lines of emission monitoring instruments. Primary amines and formaldehyde were found to quickly react on inlet surfaces to form the respective Schiff-base condensation products. Secondary and tertiary amines did not react with formaldehyde. Schiff-base condensation reactions between primary amines and formaldehyde were also observed to occur on the ∼110 m long inlet line that connects the absorber stack of the amine-based PCCC facility at Mongstad to the FT-IR and PTR-ToF-MS emission monitors. Emissions of primary amines and formaldehyde may be underestimated if condensation reactions of these species in inlet lines are not taken into account. The PTR-ToF-MS monitor does, however, also quantitatively detect the Schiff-base condensation products, making it straightforward to derive the correct amine and formaldehyde concentrations in the amine wash gas. [ABSTRACT FROM AUTHOR]

In 2015, the CO 2 Technology Centre Mongstad (TCM DA), operated a test campaign using aqueous monoethanolamine (MEA) solvent at 30 wt%. The main objective was to demonstrate and document the performance of the TCM DA Amine Plant located in Mongstad, Norway. This paper will present several aspects concerning degradation of the solvent and atmospheric emissions from amine based CO 2 removal processes. The work aims to; (1) quantify the amounts and compositions of the degraded solvent (2) report results from atmospheric emissions measurements of amines and amine based degradation products; and (3) present Ambient Air measurement done during a 2 month campaign. [ABSTRACT FROM AUTHOR]

The atmospheric chemistry of (CH 3 ) 3 CNH 2 ( tert -butylamine, t BA) and (CH 3 ) 2 (CH 2 OH)CNH 2 (2-amino-2-methyl-1-propanol, AMP) has been studied by quantum chemistry methods and in photo-oxidation experiments in the EUPHORE chamber in Valencia (Spain). Aerosol formation and composition has been quantified. Yields of nitramines and other products in the photo-oxidations have been determined and complete photo-oxidation schemes including branching between the major reaction routes have been obtained. [ABSTRACT FROM AUTHOR]

Extensive atmospheric emission monitoring has been conducted at the CO 2 Technology Centre Mongstad (TCM DA) during amine based post-combustion CO 2 capture. The TCM DA amine plant was operated with an aqueous monoethanolamine (MEA) solvent system, treating flue gas from a combined heat and power (CHP) plant. Emission monitoring was conducted by a Fourier Transform Infrared (FTIR) Spectroscopy analyzer, a Proton Transfer Reaction Time-of-Flight Mass Spectrometry (PTR-TOF- MS) analyzer, and manual isokinetic sampling followed by off-line analysis in the laboratory. Atmospheric emissions of MEA were very low throughout the entire campaign, ranging from a few to a few hundred parts per billion (ppb, 1 ppb = 10 -9 v/v). Atmospheric emissions of MEA amine based degradation products such as nitrosamines and nitramines were below detectable levels. Atmospheric emissions of ammonia (NH3) were in the low ppm range. Methylamine was emitted at low ppb range. Absorber wash water sections were found to effectively reduce atmospheric emissions from amine based solvent system. [ABSTRACT FROM AUTHOR]

Abstract: The atmospheric photo-oxidation of 2-aminoethanol (MEA, NH2CH2CH2OH) was studied at the European Photochemical Reactor, EUPHORE, in Valencia (Spain). The experiments were carried out under different atmospherically relevant NOx conditions. The photo-oxidation was monitored in situ by FT-IR and on-line by PTR-TOF-MS, and samples were collected on various adsorbents for subsequent off-line analysis. The formation of particles was monitored by SMPS and AMS on-line instruments and filter sampling followed by LC/HRMS(TOF) analysis. The obtained results suggest that more than 80% of the reaction between MEA and OH radicals takes place at–CH2–, while less than 10% occurs at–NH2 and at–CH2OH, respectively. The major observed products (>80%) in the photo-oxidation were formamide (NH2CHO) and formaldehyde (CH2O). Minor detected products (<10%) were amino acetaldehyde (NH2CH2CHO) and 2-oxo acetamide (NH2C(O)CHO). 2-nitroamino ethanol, O2NNHCH2CH2OH, was confirmed as product in the experiments. [Copyright &y& Elsevier]

Abstract: The effect on indoor air quality of an air purifier based on photocatalytic oxidation (PCO) was determined by different measuring techniques: sensory assessments of air quality made by human subjects, Proton-Transfer-Reaction Mass Spectrometry (PTR-MS) and chromatographic methods (Gas Chromatography/Mass Spectrometry and High-Pressure Liquid Chromatography with UV detection). The experiment was conducted in a simulated office, ventilated with 0.6 h−1, 2.5 h−1 and 6 h−1, in the presence of additional pollution sources (carpet, chipboard and linoleum). At the lowest air change rate, additional measurements were made with no pollution sources present in the office. All conditions were tested with the photocatalytic air purifier turned on and off. The results show that operation of the air purifier in the presence of pollutants emitted by building materials and furniture improves indoor air quality, as documented by sensory assessments made by human subjects. It also reduces concentrations of many chemical compounds present in the air as documented by the PTR-MS technique. For the lowest ventilation, results from measurements using the chromatographic methods have similar tendency, however many of the 50 compounds that were targeted for analysis were not detected at all, independent of whether the purifier was on or off. For the two conditions with higher ventilation the results were inconclusive. [Copyright &y& Elsevier]

Abstract: The experiment presented in this report was performed in a simulated aircraft cabin to evaluate the air cleaning effects of two air purification devices that used photocatalytic oxidation (PCO) technology. Objective physical, chemical and physiological measurements and subjective human assessments were used for the evaluation. Comparisons were made between conditions with and without the PCO units installed in the re-circulated air system. Four groups of 17 subjects were exposed for 7h to each test condition. Chemical analysis indicates that ethanol, isoprene and toluene were decomposed by oxidation in the PCO units tested. However, some intermediate products, such as formaldehyde and acetaldehyde, were detected. Physiological measurements did not show any significant effects of the two PCO units except that skin dryness was reduced by operating PCO unit 2. Both positive and negative effects of using PCO units on subjective assessments were observed after the first 31/4 hours of exposure. After 6h of exposure, a positive effect of using either PCO unit on symptoms of dizziness and claustrophobia was observed. [Copyright &y& Elsevier]

Proton-transfer-reaction mass spectrometry (PTR-MS) was used as an analytical tool to measure gas-phase concentrations of short-chain fatty acids. Chemical ionisation of C2–C6 carboxylic acids by PTR-MS produced intense protonated molecular ions (with traces of hydrates) along with acylium ion fragments. Gas-phase concentrations were derived using the established method for calculating PTR-MS sensitivity factors. Henry's law constants of carboxylic acids for aqueous solutions at 40°C were determined. Direct monitoring of volatile fatty acids, known to be associated with secretions from the human axilla, was performed via a specially designed transfer device situated in the axilla. Mass spectral data corresponded with the findings of a sensory assessor. [Copyright &y& Elsevier]

In situ measurements of CO, NOx, PM10 and certain organic compounds took place over an 11 day period encompassing a 12 h motorway blockade. Located within the Inn valley (Tirol, Austria), the monitoring site experiences varying meteorological conditions and traffic frequency throughout the day which both strongly influence air pollutant levels. Early morning increases of NOx, PM10 and aromatic hydrocarbons were clearly correlated with rising traffic. Midday minima and afternoon maxima may be explained by changing wind conditions and varying inversion layer dynamics. Night time lows in concentrations can be explained by minimal traffic activity. Classification of compound sources was made through grouping of data, separated into times when heavy duty vehicles (HDV) were permitted to use the motorway and HDV-ban periods. Increased levels of NOx and PM10 were observed from data that included periods of high HDV numbers, with levels decreasing significantly during HDV-ban periods. In contrast, the aromatic hydrocarbons and CO displayed only minor variations between these two periods. Furthermore, on typical workdays NOx levels reached a maximum that corresponded to a peak in HDV numbers, whereas the aromatic compounds peaked later when LDV numbers had reached their maximum. Our findings give strong evidence that increased NOx and PM10 levels can be predominantly attributed to HDV traffic. Principal components analyses for the separated data further support this conclusion. [Copyright &y& Elsevier]

• A 150 kg/h CO 2 capture plant was operated successfully for more than 5000 h. • Flue gas from waste incinerators was processed for later scale-up to >50 t/h CO 2. • Emissions of amine solvent and degradation products were well below NIPH guidelines. • Specific steam consumption was in-line with expectations. • Solvent degradation rate was in-line with expectations. Fortum Oslo Varme AS (FOV) decided (in July 2018) to build a 1:350 scale pilot plant to demonstrate that the selected Shell's CANSOLV capture technology using solvent DC-103 is suitable for cleaning CO₂ from the exhaust gases of their waste to energy (WtE) plant at Klemetsrud in Oslo, Norway. This paper presents the most important measurement data and results from a pilot plant testing campaign from March to December 2019. The project stated requirements for the successful completion of the first pilot plant campaign were at least 2000 operational hours and total amine emissions lower than 0.4 ppmv on average over the last 500 h of testing. Emphasis is on the online emission measurement results both with and without an aerosol emissions mitigation system located downstream of the capture unit. The impact of perturbations in the plant operating conditions and inlet gas quality is discussed, in particular the particulates content. The pilot plant campaign achieved its primary purpose of demonstrating low amine emissions. It also produced important data on absorbent degradation in actual operation on WtE flue gas while confirming other performance parameters such as CO 2 capture efficiency, steam consumption and CO 2 product purity. Thus, it can be concluded that the all requirements according to objectives of the pilot campaign were successfully met. [ABSTRACT FROM AUTHOR]

Abstract: Oxygen was used as a source gas in a conventional Innsbruck PTR-MS instrument to produce O2 + ions as chemical ionization (CI) reagents instead of H3O+ ions. The use of O2 + ions as CI reagents allows for fast, highly sensitive and specific measurements of gas-phase ammonia (NH3) via the electron transfer reaction O2 + +NH3 →NH3 + +O2. The instrument was tested to be linear in the 2–2000ppbv range. Instrument sensitivity was observed to be humidity-independent and amounted to ∼40cps/ppbv. The instrumental background was determined by sampling NH3-free air from a heated platinum/palladium catalyst. A humidity-dependent increase of the instrumental background from 70pptv at dry conditions to 470pptv at humid conditions was observed. The corresponding 2σ-detection limits at 1s signal integration time were 90pptv for dry conditions and 230pptv for humid conditions, respectively. The observed background may be intrinsically formed in the instrument''s ion source but it may also be the result of incomplete NH3 oxidation in the catalyst used for zeroing. The reported background levels and detection limits are thus to be considered as upper limits. The 1/e response time of the instrument was in the range of 3–5s. The PTR-MS instrument was successfully deployed in the field to monitor changes in gas-phase NH3 concentrations in the few seconds to tens of seconds time range. Laboratory intercomparison measurements between the PTR-MS instrument and a commercial NH3 analyzer (AiRRmonia) were in good agreement. The use of O2 + ions as CI reagents will significantly improve the analytical capabilities of the Innsbruck PTR-MS instrument. [Copyright &y& Elsevier]

Abstract: During the 2002 summer intensive field campaign of BEWA2000 a proton-transfer-reaction mass spectrometer (PTR-MS) was used for online determination of volatile organic compounds (VOC) emitted by Norway spruce (Picea abies L. [Karst]) twigs in a dynamic sampling enclosure. Emissions of isoprenoids (isoprene and monoterpenes) and oxygenated VOC (OVOC; acetaldehyde, acetone, methanol, and ethanol) were investigated. Emissions showed clear diurnal patterns with high daytime emission rates amounting to 1.8μgCg−1 dwth−1 for the sum of monoterpenes and in the range of 0.1 to 0.6μgCg−1 dwth−1 for isoprene>acetone>ethanol>methanol. Data were used to validate existing models on isoprene and monoterpene emissions and to discuss environmental and physiological factors affecting VOC emissions. Isoprene and acetaldehyde emission rates were best modelled applying the Guenther 1993 temperature and solar radiation algorithm. Emissions of monoterpenes, acetone and ethanol were best described by a temperature-only exponential algorithm. Using these model approaches a maximum emission variability of 66% was covered (isoprene). Poor r 2 values ranging from 0.15 to 0.42 were typical for oxygenated VOC emission modelling indicating the need for model improvement e.g. development of process-based models describing the emission as a result of biochemical de novo synthesis as well as physico-chemical transport properties inside the leaves. [Copyright &y& Elsevier]

Abstract: A relaxed-eddy-accumulation set-up using an online gas-chromatographic technique and proton-transfer-reaction mass spectrometry was applied to determine isoprenoid fluxes above a Norway spruce forest in July 2001/2002. The system was quality assured and its suitability for determination of canopy fluxes of isoprenoids was demonstrated. Flux measurements of oxygenated hydrocarbons failed the data quality check due to artefacts presumably arising from line and ozone-scrubber effects. Observations of turbulent fluxes of isoprenoids during the two field experiments show good agreements with primary flux data derived from enclosure measurements and modelling results using a canopy-chemistry emission model (CACHE). For monoterpenes maximum daytime fluxes of more than were observed, isoprene fluxes reached 1–. [Copyright &y& Elsevier]

Quenching rate constants for NO+(v=1) and NO+(v=4) in collisions with Ar have been measured from near thermal energy up to 0.5 eV mean relative kinetic energy in a selected ion flow drift tube. The rate constants increase dramatically with KECM indicating that the quenching is dominated by the short range repulsive interaction. At higher energies the data fit linear Landau–Teller plots. These are the first L–T plots obtained for ion quenching by other than a He quencher. [Copyright &y& Elsevier]

Fires in waste facilities are a common occurrence. Since many waste facilities are located adjacent to densely populated areas, these fires could potentially expose large populations to the emitted pollutants. However, at the moment there are only few field studies investigating the impact of waste fire emissions on air quality since the unpredictable nature of these events makes them challenging to capture. This study investigated the impact of a large and persistent un-prescribed fire in a waste storage facility in Stockholm county, Sweden, on the local air quality of two residential areas in close proximity to the fire. In-situ measurements of particulate matter, black carbon and nitrogen oxide concentrations were conducted both during open burning and after the fire was fully covered. In addition, filter samples were collected for offline analysis of organic composition, metal content and toxicity. Strongly increased concentrations of PM 10 , PM 2.5 and black carbon were found during the open burning period, especially when the wind was coming from the direction of the fire. In addition, elevated concentrations of particulate heavy metals and polycyclic aromatic hydrocarbons were observed in the air during the open burning period. These results show that waste fires can have a strong impact on the air quality of nearby residential areas. • Increased PM 10 , PM 2.5 and black carbon when wind comes from direction of waste fire. • Elevated concentrations of particulate heavy metals and PAHs during open burning. • Waste fires can have a strong impact on air quality of nearby residential areas. [ABSTRACT FROM AUTHOR]

Map of plant functional type (PFT) is one of key information in estimating the bottom-up biogenic emissions. This study investigated the performance of three different maps of PFT on biogenic emissions in South Korea: i) PFT map from the MODerate resolution Imaging Spectroradiometer (MODIS) satellite sensor onboard Terra-/Aqua-satellites (MPFT); ii) PFT map from the Environmental Geographic Information System (EGIS) provided by the Korean Ministry of Environment (EPFT); and iii) PFT map from the Forest Geographic Information System (FGIS) established by the Korea Forest Service (FPFT). These three different vegetation distributions were used as input information into the Model of Emissions of Gases and Aerosols from Nature (MEGAN) model. The biogenic emissions estimated by the MEGAN model simulations were then evaluated by comparisons between the Community Multi-scale Air Quality (CMAQ) simulated mixing ratios of biogenic species with ground- and aircraft-borne mixing ratios during the period of the Korea–United States Air Quality (KORUS-AQ) campaign. The analyses found that the simulation using the FPFT map, which has been regarded as 'ground truth', produced the best results in terms of several statistical metrics. For example, among the three experiments, the simulation with the FPFT map produced the best index of agreement (IOA) of 0.76 and the lowest normalized mean bias (NMB) of 5.61%, in comparison with ground-based isoprene observations. The simulations with the MPFT map also performed reasonably, showing low NMBs of −42.13% and −14.87% for the isoprene and the first-generation products of isoprene, respectively, in comparison with the DC-8 airborne observations. In addition, the applications of the MPFT map to the MEGAN modeling showed significant overestimations in the mixing ratios of biogenic species over the SoBaek (SB) mountain ranges. It was believed that this was due to the overestimated density of broadleaf deciduous temperate trees over the SB mountain ranges in the MPFT map. On the other hand, the EPFT map showed the worst performances, which might be related to crude classification of vegetation. This study also suggests two important possibilities. First, the current isoprene-related photochemistry appears to be highly uncertain, based on large underestimations of the first-generation products of isoprene, in comparison with observations. Second, the emission factors of monoterpenes in the MEGAN model may be too small, based on large underestimations of monoterpenes, in comparison with observations. [Display omitted] • Biogenic emissions were estimated via MEGAN model with three different vegetation. • The FGIS dataset made the best performances in the CMAQ model simulations. • Overestimated distributions of broadleaf trees were found in the MODIS land cover. • Under-simulated isoprene oxidation products and monoterpenes were investigated. [ABSTRACT FROM AUTHOR]

Predictions of O 3 , CO, total NO y and individual NO y species (NO, NO 2 , HNO 3 , PAN, alkyl nitrates and aerosol nitrate) from a fine resolution regional air quality modeling system for the South Coast Air Basin (SoCAB) and San Joaquin Valley Air Basin (SJVAB) of California are presented and evaluated for the 2008 ARCTAS-CARB campaign. The measurements of the chemical compounds from the fire plumes during the field campaign allow for the evaluation of the model's ability to simulate fire-influenced air masses as well. In general, the model successfully simulated the broad spatial distribution of chemical compounds in both air basins as well as the variation within the basins. Using inventories that reflect 2008 emissions levels, the model performed well in simulating NO x (NO + NO 2 ) in SoCAB. Therefore, the under prediction of O 3 over these areas is more likely caused by uncertainties with the VOC emissions, chemistry, or discrepancies in the meteorology. The model did not capture the relatively high levels of O 3 , and some reactive nitrogen species that were measured off shore of the SoCAB, indicating potential missing sources or the transport from on shore to off shore was not successfully captured. In SJVAB, the model had good performance in simulating different chemical compounds in the Fresno and Arvin areas. However, enhanced concentrations of O 3 , NO x , HNO 3 and PAN near dairy farms were significantly underestimated in the model. Negative biases also exist for O 3 and HNO 3 near oil fields, suggesting larger uncertainties associated with these emission sources. While the model simulated the total NO y mixing ratios reasonably well, the prediction for partitioning between individual compounds showed larger uncertainties in the model simulation. Although the fire emissions inventory was updated to include the latest emissions estimates and speciation profiles, our model shows limited improvement in simulating the enhancement of O 3 , CO, and PAN under fire impact as compared to a previous version of the modeling system. Further improvements in simulating fire emissions, especially the timing and the plume injection heights, are desired in order to better simulate the impact of fires. [ABSTRACT FROM AUTHOR]

This paper presents airborne measurements of multiple atmospheric trace constituents including greenhouse gases (such as CO 2 , CH 4 , O 3 ) and biomass burning tracers (such as CO, CH 3 CN) downwind of an exceptionally large wildfire. In summer 2013, the Rim wildfire, ignited just west of the Yosemite National Park, California, and burned over 250,000 acres of the forest during the 2-month period (17 August to 24 October) before it was extinguished. The Rim wildfire plume was intercepted by flights carried out by the NASA Ames Alpha Jet Atmospheric eXperiment (AJAX) on 29 August and the NASA DC-8, as part of SEAC 4 RS (Studies of Emissions, Atmospheric Composition, Clouds and Climate Coupling by Regional Surveys), on 26 and 27 August during its intense, primary burning period. AJAX revisited the wildfire on 10 September when the conditions were increasingly smoldering, with slower growth. The more extensive payload of the DC-8 helped to bridge key measurements that were not available as part of AJAX (e. g. CO). Data analyses are presented in terms of emission ratios (ER), emission factors (EF) and combustion efficiency and are compared with previous wildfire studies. ERs were 8.0 ppb CH 4 (ppm CO 2 ) −1 on 26 August, 6.5 ppb CH 4 (ppm CO 2 ) −1 on 29 August and 18.3 ppb CH 4 (ppm CO 2 ) −1 on 10 September 2013. The increase in CH 4 ER from 6.5 to 8.0 ppb CH 4 (ppm CO 2 ) −1 during the primary burning period to 18.3 ppb CH 4 (ppm CO 2 ) −1 during the fire's slower growth period likely indicates enhanced CH 4 emissions from increased smoldering combustion relative to flaming combustion. Given the magnitude of the Rim wildfire, the impacts it had on regional air quality and the limited sampling of wildfire emissions in the western United States to date, this study provides a valuable dataset to support forestry and regional air quality management, including observations of ERs of a wide number of species from the Rim wildfire. [ABSTRACT FROM AUTHOR]

Data collected during the 2011 DISCOVER-AQ field campaign in the Baltimore Washington region were used to evaluate CO and NO x emissions in the National Emissions Inventory (NEI). The average emissions ratio for the region was seen to be 11.2 ± 1.2 mol CO/mol NO x , 21% higher than that predicted by the NEI. Comparisons between in situ and remote observations and CMAQ model output show agreement in CO emissions of 15 ± 11% while NO x emissions are overestimated by 51–70% in Maryland. Satellite observations of CO by MOPITT show agreement with the Community Multiscale Air Quality (CMAQ) model within 3% over most of the eastern United States. CMAQ NO y mixing ratios were a factor of two higher than observations and result from a combination of errors in emissions and PAN and alkyl nitrate chemistry, as shown by comparison of three CMAQ model runs. Point source NO x emissions are monitored and agree with modeled emissions within 1% on a monthly basis. Because of this accuracy and the NEI assertion that approximately 3/4 of emissions in the Baltimore Washington region are from mobile sources, the MOVES model's treatment of emissions from aging vehicles should be investigated; the NEI overestimate of NO x emissions could indicate that engines produce less NO x and catalytic converters degrade more slowly than assumed by MOVES2010. The recently released 2011 NEI has an even lower CO/NO x emissions ratio than the projection used in this study; it overestimates NO x emissions by an even larger margin. The implications of these findings for US air quality policy are that NO x concentrations near areas of heavy traffic are overestimated and ozone production rates in these locations are slower than models indicate. Results also indicate that ambient ozone concentrations will respond more efficiently to NO x emissions controls but additional sources may need to be targeted for reductions. [ABSTRACT FROM AUTHOR]

Abstract: An instrumented DC-8 aircraft was employed to perform airborne observations in rural and urban environs of California during the summer 2008 NASA ARCTAS-CARB campaign. The fortuitous occurrence of large wildfire episodes in Northern California allowed for studies of fire emissions, their composition, and their interactions with rural and urban air. Relative to CO, emissions of HCN were shown to vary non-linearly with fire characteristics while those of CH3CN were nearly unchanged, making the latter a superior quantitative tracer of biomass combustion. Although some fire plumes over California contained little NOx and virtually no O3 enhancement, others contained ample VOCs and sufficient NOx, largely from urban influences, to result in significant ozone formation. The highest observed O3 mixing ratios (170 ppb) were also in fire-influenced urban air masses. Attempts to simulate these interactions using CMAQ, a high-resolution state of the art air quality model, were only minimally successful and indicated several shortcomings in simulating fire emission influences on urban smog formation. A variety of secondary oxidation products (e.g. O3, PAN, HCHO) were substantially underestimated in fire-influenced air masses. Available data involving fire plumes and anthropogenic pollution interactions are presently quite sparse and additional observational and mechanistic studies are needed. [Copyright &y& Elsevier]

Abstract: The sectoral and regional contributions from northern hemisphere anthropogenic and biomass burning emission sectors to black carbon (BC) distributions over the continental United States (CONUS) in summer 2008 are studied using the Sulfur Transport and dEposition Model (STEM). North American (NA) emissions heavily (>70% of total emissions) affect the BC levels from the surface to ∼5 km, while non-NA plumes compose more than half of the BC above ∼5 km. Among all sectors, NA and non-NA biomass burning, NA transportation and non-NA residential emissions are the major contributors. The sectoral contributions vary among ten regions defined by the US Environmental Protection Agency (EPA): NA anthropogenic emissions enhance northeastern US BC levels; biomass burning strongly impacts northern California and southeastern US; and the influence of extra-regional plumes is largest in the northwestern US but extends to eastern US. The mean contribution from non-NA sources to US surface BC is ∼0.05 μg m−3, with a maximum value of ∼0.11 μg m−3 in the northwestern US. The non-NA contributions to column BC are higher than to surface BC, ranging from 30% to 80%, depending on region. EPA region 8 is most sensitive to extra-regional BC, partially explaining the observed increasing BC trend there during the past decades associated with the increasing Asian BC emissions. Measurements from the June 24 DC-8 flight during the ARCTAS-CARB field campaign show that BC/(organic matter + nitrate + sulfate) mass ratios fairly well represent BC''s warming potential over southern California, which can be approximated by BC/(organic matter + sulfate) and BC/sulfate for plumes affected and unaffected by fires, respectively. The responses of BC/(organic matter + sulfate) and BC/sulfate to removing each emission sector are further discussed, indicating that mitigating NA transportation emissions has the highest potential for regional air quality and climate co-benefits. [Copyright &y& Elsevier]

Abstract: The sensitivity of biogenic emission estimates and air quality model predictions to the characterization of land use/land cover (LULC) in southeastern Texas was examined using the Global Biosphere Emissions and Interactions System (GloBEIS) and the Comprehensive Air Quality Model with extensions (CAMx). A LULC database was recently developed for the region based on source imagery collected by the Landsat 7 Enhanced Thematic Mapper-Plus sensor between 1999 and 2003, and field data for land cover classification, species identification and quantification of biomass densities.  Biogenic emissions estimated from the new LULC data set showed good general agreement in their spatial distribution, but were approximately 40% lower than emissions from the LULC data set currently used by the State of Texas, primarily because of differences in the biomass estimates of key species such as Quercus. Predicted ozone mixing ratios using the biogenic emissions produced from the new LULC data set were as much as 26 ppb lower in some areas on some days, depending on meteorological conditions. Satellite data and image classification techniques provide useful tools for mapping and monitoring changes in LULC. However, field validation is necessary to link species and biomass densities to the classification system used for accurate biogenic emissions estimates, especially in areas such as riparian corridors that contain dense spatial coverage of key species. [Copyright &y& Elsevier]

Abstract: The volatile compositions of 192 olive oil samples from five different European countries were investigated by PTR-MS sample headspace analysis. The mass spectra of all samples showed many masses with high abundances, indicating the complex VOC composition of olive oil. Three different PLS-DA models were fitted to the data to classify samples into ‘country’, ‘region’ and ‘district’ of origin, respectively. Correct classification rates were assessed by cross-validation. The first fitted model produced an 86% success rate in classifying the samples into their country of origin. The second model, which was fitted to the Italian oils only, also demonstrated satisfactory results, with 74% of samples successfully classified into region of origin. The third model, classifying the Italian samples into district of origin, yielded a success rate of only 52%. This lower success rate might be due to either the small class set, or to genuine similarities between olive oil VOC compositions on this tight scale. [Copyright &y& Elsevier]

Biogenic emissions of hydrocarbons, primarily isoprene, dominate the VOC emission inventory in eastern Texas. Air quality model predictions of isoprene in southeast Texas were evaluated using ground and aircraft measurements collected during the Texas Air Quality Study 2000. The effects of two different vertical mixing schemes on model predictions of isoprene concentrations were also evaluated. The photochemical and biogenic emission estimation models used were the Comprehensive Air Quality Model with Extensions and the Global Biosphere Emissions and Interactions System. Ground level isoprene concentrations predicted by the models showed markedly good agreement with measured diurnal isoprene patterns. The vertical mixing schemes were most influential on surface concentrations, resulting in differences of as much as 270% in modeled isoprene concentrations. The model over predicted observations from airborne canister samples by as much as a factor of two over rural areas, but under predicted observations over urban areas. Modeled isoprene concentrations were also compared with measurements from an airborne Proton Transfer Reaction Mass Spectrometer, and the results indicated under prediction of isoprene by the model over urban areas, but better agreement in rural areas. The impacts of the vertical mixing schemes on isoprene concentrations were less direct aloft than at the surface. The resulting vertical redistribution of isoprene affected transport rates, chemistry, and the accumulation of mass. As a result, differences in concentrations aloft ranged from none to as much as 30%. This study reinforces the challenges of air quality model validation for highly reactive species such as isoprene, and the need for carefully controlled studies of biogenic emissions and chemical processing during different meteorological conditions in regions with spatially heterogeneous land use. [Copyright &y& Elsevier]

Continuous measurements of CO, NO, NO2, PM10, benzene and toluene were conducted over a one-year period at a motorway location in the alpine Inn valley. Diurnal changes in concentrations of detected compounds were observed to vary according to traffic type and frequency, and meteorological conditions of the valley atmosphere, which were both additionally recorded at this location. Seasonal variations were also clearly seen, with lowest levels of compound abundances present in summer and highest levels in winter. Annual mean abundances of compounds were assessed with respect to guideline limits and it was found that NO2 and PM10 exceeded their legislation thresholds. This investigation also included the first continuous year-long measurements of benzene at this location, yielding an annual mean volume mixing ratio of 0.6ppbV, which is well within the EU guideline limit of 1.5ppbV. Additionally, benzene abundances were found to correlate well with CO concentrations. A significant correlation was also found between toluene and benzene. However, the ratio toluene:benzene shifted from about 2:1 in summer to approximately 1:1 in winter. This may be explained by a strong evaporative and therefore temperature dependent toluene source, while benzene concentrations mainly result from non-ambient temperature dependent exhaust pipe emissions. This seasonal variation must be taken into account whenever this ratio is used to determine the chemical age of an air mass. [Copyright &y& Elsevier]

Abstract: Diurnal mixing ratios of aldehydes and ketones were investigated during two joint experiments in summer months to identify biogenic contributions from coniferous forests to tropospheric chemistry. In a Norway spruce forest, the diurnal variation of carbonyl compounds was measured at 12m (in the treetop) and at 24m (above the canopy). The main findings of the experiment are that acetone (up to 9.1ppbv), formaldehyde (up to 6.5ppbv), acetaldehyde (up to 5.5ppbv) and methyl ethyl ketone (MEK, up to 1.8ppbv) were found in highest concentrations. For all major compounds with the exception of MEK, primary emissions are supposed. From α-pinene oxidation, pinonaldehyde was found with its peak concentrations (up to 0.15ppbv) during the early morning hours. The diurnal variation of concentrations for most other compounds shows maximum concentrations near midday in 2,4-dinitrophenylhydrazine (DNPH) measurements but not for proton-transfer reaction mass spectrometry (PTR-MS) measurements of acetaldehyde and acetone. A clear correlation of carbonyl compound concentration to the radiation intensity and the temperature (R 2=0.66) was found. However, formaldehyde did not show distinct diurnal variations. A very high correlation was observed for both heights between mixing ratios of acetaldehyde and acetone (R 2=0.84), acetone and MEK (R 2=0.90) as well as acetaldehyde and MEK (R 2=0.88) but not for formaldehyde and the others. For the most time, the observed carbonyl compound concentrations above the canopy are higher than within the forest stand. This indicates an additional secondary formation in the atmosphere above the forest. The differences of acetone and acetaldehyde mixing ratios detected by DNPH technique and the PTR-MS could not be fully clarified by a laboratory intercomparison. [Copyright &y& Elsevier]