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A reduction in gaseous pollutants is an important method for mitigating PM2.5 concentration in the atmosphere, and the reduction in SO2/NH3/NOx is beneficial to control secondary inorganic aerosols in PM2.5. In this study, the Weather Research and Forecasting model with Chemistry model (WRF-Chem) was applied to study the impact on the PM2.5 and its secondary inorganic aerosols using the scenario simulation method in the Beijing–Tianjin–Hebei (BTH) region. The results showed that the BTH region is characterized by being NH3-rich and having a higher [NH4+]/[SO42−] ratio in southern BTH, with a ratio of more than 6.0. Source contribution to PM2.5 was highest in the 30%_SO2_40%_NH3_40%_NOx scenario, with a contribution ratio of 6.8%, followed by 3.8% contribution in the 30%_SO2_40%_NH3 scenario, and a 3.4% contribution in the 30%_SO2_60%_NH3_60%_NOx scenario. These results indicate that synergistic reduction measures may be suitable for controlling PM2.5 concentrations. A lower sensitivity factor, β value between PM2.5 and NH3 suggests that solely reducing NH3 emissions is not beneficial for the BTH region. However, this study indicates that the sensitivity of NO3− would improve significantly if NH3 emissions are reduced sharply. A slight reduction in NH3 was found to be beneficial for controlling NO3− in medium and small cities, while a significant decrease in NH3 would be more suitable for mega-cities. The study also observed that SO42− and its constituents continued to decrease with a consistent β value of approximately 0.14 in the 30%_SO2_%_NH3 scenario and between 10.5 and 12.8 in the 30%_SO2_%_NH3_%_NOx scenario. These findings suggest that a synergistic reduction in SO2-NH3-NOx emissions may be more effective in reducing PM2.5 concentrations and its secondary inorganic aerosols (SIAs). However, it is important to ensure that the reduction in NH3 and NOx exceeds 60% in low SO2 concentration conditions. [ABSTRACT FROM AUTHOR]

Air quality in Europe continues to remain poor in many areas, with regulation limits often exceeded by many countries. The EU Life-IP PREPAIR Project, involving administrations and environmental protection agencies of eight regions and three municipalities in Northern Italy and Slovenia, was designed to support the implementation of the regional air quality plans in the Po Valley, one of the most critical areas in Europe in terms of pollution levels. In this study, four air quality modelling systems, based on three chemical transport models (CHIMERE, FARM and CAMx) were applied over the Po Valley to assess the sensitivity of PM2.5 concentrations to NOx and NH3 emission reductions. These two precursors were reduced (individually and simultaneously) from 25% up to 75% for a total of 10 scenarios, aimed at identifying the most efficient emission reduction strategies and to assess the non-linear response of PM2.5 concentrations to precursor changes. The multi-model analysis shows that reductions across multiple emission sectors are necessary to achieve optimal results. In addition, the analysis of non-linearities revealed that during the cold season, the efficiency of PM2.5 abatement tends to increase by increasing the emission reductions, while during summertime, the same efficiency remains almost constant, or slightly decreases towards higher reduction strengths. Since the concentrations of PM2.5 are greater in winter than in summer, it is reasonable to infer that significant emission reductions should be planned to maximise reduction effectiveness. [ABSTRACT FROM AUTHOR]

Ammonia (NH3) emissions have a negative impact on the welfare of breeding animals, human health, and the environment. These influences of modern intensive agriculture have led to numerous protocols, national regulations, and European Directives. Following previous regulatory measures, the Commission Implementing Decision European Union (EU) 2017/302 on 15 February 2017 has established best available technique (BAT) conclusions, under Directive 2010/75/EU of the European Parliament and the Council, for the intensive rearing of poultry and pigs. This applies to intensive poultry and pig producers with a capacity of over 40,000 poultry, 750 sows, or 2000 fattening pigs. Due to the application of this directive, air emissions have been reduced by between 40% and 75% over the last 15 years. The integrated permit monitors the entire environmental burden of the farm on its surroundings (air pollution, water, soil pollution, waste production, energy use). This review aims to provide a critical overview of how member states (including the United Kingdom) are approaching the implementation of IPPC (Integrated Pollution Prevention and Control) and the conclusions of BAT in their legislation and related documents, and how they monitor NH3 emissions from intensive livestock farming. The data for this review were obtained from 2019 to 2020. [ABSTRACT FROM AUTHOR]

A reduction in gaseous pollutants is an important method for mitigating PM2.5 concentration in the atmosphere, and the reduction in SO2/NH3/NOx is beneficial to control secondary inorganic aerosols in PM2.5. In this study, the Weather Research and Forecasting model with Chemistry model (WRF-Chem) was applied to study the impact on the PM2.5 and its secondary inorganic aerosols using the scenario simulation method in the Beijing–Tianjin–Hebei (BTH) region. The results showed that the BTH region is characterized by being NH3-rich and having a higher [NH4+]/[SO42−] ratio in southern BTH, with a ratio of more than 6.0. Source contribution to PM2.5 was highest in the 30%_SO2_40%_NH3_40%_NOx scenario, with a contribution ratio of 6.8%, followed by 3.8% contribution in the 30%_SO2_40%_NH3 scenario, and a 3.4% contribution in the 30%_SO2_60%_NH3_60%_NOx scenario. These results indicate that synergistic reduction measures may be suitable for controlling PM2.5 concentrations. A lower sensitivity factor, β value between PM2.5 and NH3 suggests that solely reducing NH3 emissions is not beneficial for the BTH region. However, this study indicates that the sensitivity of NO3− would improve significantly if NH3 emissions are reduced sharply. A slight reduction in NH3 was found to be beneficial for controlling NO3− in medium and small cities, while a significant decrease in NH3 would be more suitable for mega-cities. The study also observed that SO42− and its constituents continued to decrease with a consistent β value of approximately 0.14 in the 30%_SO2_%_NH3 scenario and between 10.5 and 12.8 in the 30%_SO2_%_NH3_%_NOx scenario. These findings suggest that a synergistic reduction in SO2-NH3-NOx emissions may be more effective in reducing PM2.5 concentrations and its secondary inorganic aerosols (SIAs). However, it is important to ensure that the reduction in NH3 and NOx exceeds 60% in low SO2 concentration conditions.

Air quality in Europe continues to remain poor in many areas, with regulation limits often exceeded by many countries. The EU Life-IP PREPAIR Project, involving administrations and environmental protection agencies of eight regions and three municipalities in Northern Italy and Slovenia, was designed to support the implementation of the regional air quality plans in the Po Valley, one of the most critical areas in Europe in terms of pollution levels. In this study, four air quality modelling systems, based on three chemical transport models (CHIMERE, FARM and CAMx) were applied over the Po Valley to assess the sensitivity of PM2.5 concentrations to NOx and NH3 emission reductions. These two precursors were reduced (individually and simultaneously) from 25% up to 75% for a total of 10 scenarios, aimed at identifying the most efficient emission reduction strategies and to assess the non-linear response of PM2.5 concentrations to precursor changes. The multi-model analysis shows that reductions across multiple emission sectors are necessary to achieve optimal results. In addition, the analysis of non-linearities revealed that during the cold season, the efficiency of PM2.5 abatement tends to increase by increasing the emission reductions, while during summertime, the same efficiency remains almost constant, or slightly decreases towards higher reduction strengths. Since the concentrations of PM2.5 are greater in winter than in summer, it is reasonable to infer that significant emission reductions should be planned to maximise reduction effectiveness.

Agricultural activity greatly contributes to the secondary PM2.5 concentrations by releasing relatively large amounts of ammonia emissions. Nonetheless, studies and air quality policies have traditionally focused on industrial emissions such as NOx and SOx. To compare them, this study used a three-dimensional modeling system (e.g., WRF/CMAQ) to estimate the effects of emission control policies of agricultural and industrial emissions on PM2.5 pollution in Chungcheong, an agriculturally active region in Korea. Scenario 1 (S1) was designed to estimate the effect of a 30% reduction in NH3 emissions from the agro-livestock sector on air pollution. Scenario 2 (S2) was designed to show the air quality under a mitigation policy on NOx, SOx, VOCs, and primary PM2.5 from industrial sources, such as power plants and factories. The results revealed that monthly mean PM2.5 in Chungcheong could decrease by 3.6% (1.1 µg/m3) under S1 with agricultural emission control, whereas S2 with industrial emission control may result in only a 0.7~1.1% improvement. These results indicate the importance of identifying trends of multiple precursor emissions and the chemical environment in the target area to enable more efficient air quality management. [ABSTRACT FROM AUTHOR]

Ammonia (NH3) emissions have a negative impact on the welfare of breeding animals, human health, and the environment. These influences of modern intensive agriculture have led to numerous protocols, national regulations, and European Directives. Following previous regulatory measures, the Commission Implementing Decision European Union (EU) 2017/302 on 15 February 2017 has established best available technique (BAT) conclusions, under Directive 2010/75/EU of the European Parliament and the Council, for the intensive rearing of poultry and pigs. This applies to intensive poultry and pig producers with a capacity of over 40,000 poultry, 750 sows, or 2000 fattening pigs. Due to the application of this directive, air emissions have been reduced by between 40% and 75% over the last 15 years. The integrated permit monitors the entire environmental burden of the farm on its surroundings (air pollution, water, soil pollution, waste production, energy use). This review aims to provide a critical overview of how member states (including the United Kingdom) are approaching the implementation of IPPC (Integrated Pollution Prevention and Control) and the conclusions of BAT in their legislation and related documents, and how they monitor NH3 emissions from intensive livestock farming. The data for this review were obtained from 2019 to 2020.

Agricultural activity greatly contributes to the secondary PM2.5 concentrations by releasing relatively large amounts of ammonia emissions. Nonetheless, studies and air quality policies have traditionally focused on industrial emissions such as NOx and SOx. To compare them, this study used a three-dimensional modeling system (e.g., WRF/CMAQ) to estimate the effects of emission control policies of agricultural and industrial emissions on PM2.5 pollution in Chungcheong, an agriculturally active region in Korea. Scenario 1 (S1) was designed to estimate the effect of a 30% reduction in NH3 emissions from the agro-livestock sector on air pollution. Scenario 2 (S2) was designed to show the air quality under a mitigation policy on NOx, SOx, VOCs, and primary PM2.5 from industrial sources, such as power plants and factories. The results revealed that monthly mean PM2.5 in Chungcheong could decrease by 3.6% (1.1 µg/m3) under S1 with agricultural emission control, whereas S2 with industrial emission control may result in only a 0.7~1.1% improvement. These results indicate the importance of identifying trends of multiple precursor emissions and the chemical environment in the target area to enable more efficient air quality management.

An analyzer for measuring NH3 emitted from a combustion process has been developed based on a simple non-dispersive infrared (NDIR) technique because of its cost-effective benefit. The weakness of the NDIR analyzer due to interference and zero-drift has been overcome. A least-interfering bandpass filter (BPF) was found and manufactured to compensate for the interfering effects of gases emitted from a combustion process (e.g., CO, NOx, SO2, CO2, H2O, HCl, formaldehyde, acetaldehyde and toluene). It was found that there was no significant interference in the least-interfering BPF with respect to gases of concern. Measurement errors by the analyzer were less than 2.5% in a range of 1 to 10 ppmv of NH3 compared to a standard method when the compound was measured in complicated mixing gases. For the zero-drift, using BPFs with identical center wavelength with respect to different incident infrared intensity was found to help minimize the zero-drift of the NDIR analyzer. As a result, the analyzer could cut approximately 19% of zero-drift caused by the aging effect of both IR source and detector. It suggests that the analyzer could be applied for measuring NH3 emitted from combustion processes with good accuracy and reproducibility.

Ammonia (NH3), the most prevalent alkaline gas in the atmosphere, plays a significant role in PM2.5 formation, atmospheric chemistry, and new particle formation. This paper reviews quantification of [NH3] through measurements, satellite-remote-sensing, and modeling reported in over 500 publications towards synthesizing the current knowledge of [NH3], focusing on spatiotemporal variations, controlling processes, and quantification issues. Most measurements are through regional passive sampler networks. [NH3] hotspots are typically over agricultural regions, such as the Midwest US and the North China Plain, with elevated concentrations reaching monthly averages of 20 and 74 ppbv, respectively. Topographical effects dramatically increase [NH3] over the Indo-Gangetic Plains, North India and San Joaquin Valley, US. Measurements are sparse over oceans, where [NH3] ≈ a few tens of pptv, variations of which can affect aerosol formation. Satellite remote-sensing (AIRS, CrIS, IASI, TANSO-FTS, TES) provides global [NH3] quantification in the column and at the surface since 2002. Modeling is crucial for improving understanding of NH3 chemistry and transport, its spatiotemporal variations, source apportionment, exploring physicochemical mechanisms, and predicting future scenarios. GEOS-Chem (global) and FRAME (UK) models are commonly applied for this. A synergistic approach of measurements↔satellite-inference↔modeling is needed towards improved understanding of atmospheric ammonia, which is of concern from the standpoint of human health and the ecosystem.

Flux measurements with the aerodynamic gradient method (AGM) performed with a single analyzer measuring non-simultaneously at two heights have routinely been conducted. This study investigates the effect of this practice with calculations of single analyzer derived fluxes compared to fluxes derived from simultaneous concentration measurements at two heights for NH3. The results show a mean relative difference of less than 7% for the half-hour averaging intervals, whereas the relative difference in the cumulative loss of total ammoniacal nitrogen (TAN) is less than 4%. Scatter plots and linear regression show linear behavior with slope and intercept close to one and zero, respectively. The regression coefficients were between 0.913 and 0.966 for the simulations, but with large deviations for the single half-hour measurement interval. Changes in the starting height and averaging duration at each height for the single analyzer calculations yield small differences, but the effect is minimal compared to the general uncertainty of flux determination with AGM.

Airborne particulate matter (PM) is a major health risk in urban settings. Ammonia (NH3) from vehicle exhaust is an under-recognised ingredient in the formation of inorganic PM and there remains a shortage of data to properly quantify the role of NH3 from vehicles in PM formation. An Open-path Fourier transform infra-red (OP-FTIR) spectrometer measured atmospheric NH3, carbon monoxide (CO) and carbon dioxide (CO2) at high temporal resolution (5 min) in Western Sydney over 11 months. The oxides of nitrogen (NO2 and NO; NOx) and sulphur dioxide (SO2) were measured at an adjacent air quality monitoring station. NH3 levels were maxima in the morning and evening coincident with peak traffic. During peak traffic NH3:CO ratio ranged from 0.018 to 0.022 ppbv:ppbv. Results were compared with the Greater Metropolitan Region 2008 (GMR2008) emissions inventory. Measured NH3:CO was higher during peak traffic times than the GMR2008 emissions estimates, indicating an underestimation of vehicle NH3 emissions in the inventory. Measurements also indicated the urban atmosphere was NH3 rich for the formation of ammonium sulphate ((NH4)2SO4) particulate was SO2 limited while the formation of ammonium nitrate (NH4NO3) was NH3 limited. Any reduction in NOx emissions with improved catalytic converter efficiency will be accompanied by an increase in NH3 production and potentially with an increase in NH4NO3 particulate.

An analyzer for measuring NH3 emitted from a combustion process has been developed based on a simple non-dispersive infrared (NDIR) technique because of its cost-effective benefit. The weakness of the NDIR analyzer due to interference and zero-drift has been overcome. A least-interfering bandpass filter (BPF) was found and manufactured to compensate for the interfering effects of gases emitted from a combustion process (e.g., CO, NOx, SO2, CO2, H2O, HCl, formaldehyde, acetaldehyde and toluene). It was found that there was no significant interference in the least-interfering BPF with respect to gases of concern. Measurement errors by the analyzer were less than 2.5% in a range of 1 to 10 ppmv of NH3 compared to a standard method when the compound was measured in complicated mixing gases. For the zero-drift, using BPFs with identical center wavelength with respect to different incident infrared intensity was found to help minimize the zero-drift of the NDIR analyzer. As a result, the analyzer could cut approximately 19% of zero-drift caused by the aging effect of both IR source and detector. It suggests that the analyzer could be applied for measuring NH3 emitted from combustion processes with good accuracy and reproducibility. [ABSTRACT FROM AUTHOR]

Ammonia (NH3), the most prevalent alkaline gas in the atmosphere, plays a significant role in PM2.5 formation, atmospheric chemistry, and new particle formation. This paper reviews quantification of [NH3] through measurements, satellite-remote-sensing, and modeling reported in over 500 publications towards synthesizing the current knowledge of [NH3], focusing on spatiotemporal variations, controlling processes, and quantification issues. Most measurements are through regional passive sampler networks. [NH3] hotspots are typically over agricultural regions, such as the Midwest US and the North China Plain, with elevated concentrations reaching monthly averages of 20 and 74 ppbv, respectively. Topographical effects dramatically increase [NH3] over the Indo-Gangetic Plains, North India and San Joaquin Valley, US. Measurements are sparse over oceans, where [NH3] ≈ a few tens of pptv, variations of which can affect aerosol formation. Satellite remote-sensing (AIRS, CrIS, IASI, TANSO-FTS, TES) provides global [NH3] quantification in the column and at the surface since 2002. Modeling is crucial for improving understanding of NH3 chemistry and transport, its spatiotemporal variations, source apportionment, exploring physicochemical mechanisms, and predicting future scenarios. GEOS-Chem (global) and FRAME (UK) models are commonly applied for this. A synergistic approach of measurements↔satellite-inference↔modeling is needed towards improved understanding of atmospheric ammonia, which is of concern from the standpoint of human health and the ecosystem. [ABSTRACT FROM AUTHOR]

Flux measurements with the aerodynamic gradient method (AGM) performed with a single analyzer measuring non-simultaneously at two heights have routinely been conducted. This study investigates the effect of this practice with calculations of single analyzer derived fluxes compared to fluxes derived from simultaneous concentration measurements at two heights for NH3. The results show a mean relative difference of less than 7% for the half-hour averaging intervals, whereas the relative difference in the cumulative loss of total ammoniacal nitrogen (TAN) is less than 4%. Scatter plots and linear regression show linear behavior with slope and intercept close to one and zero, respectively. The regression coefficients were between 0.913 and 0.966 for the simulations, but with large deviations for the single half-hour measurement interval. Changes in the starting height and averaging duration at each height for the single analyzer calculations yield small differences, but the effect is minimal compared to the general uncertainty of flux determination with AGM. [ABSTRACT FROM AUTHOR]

Airborne particulate matter (PM) is a major health risk in urban settings. Ammonia (NH3) from vehicle exhaust is an under-recognised ingredient in the formation of inorganic PM and there remains a shortage of data to properly quantify the role of NH3 from vehicles in PM formation. An Open-path Fourier transform infra-red (OP-FTIR) spectrometer measured atmospheric NH3, carbon monoxide (CO) and carbon dioxide (CO2) at high temporal resolution (5 min) in Western Sydney over 11 months. The oxides of nitrogen (NO2 and NO; NOx) and sulphur dioxide (SO2) were measured at an adjacent air quality monitoring station. NH3 levels were maxima in the morning and evening coincident with peak traffic. During peak traffic NH3:CO ratio ranged from 0.018 to 0.022 ppbv:ppbv. Results were compared with the Greater Metropolitan Region 2008 (GMR2008) emissions inventory. Measured NH3:CO was higher during peak traffic times than the GMR2008 emissions estimates, indicating an underestimation of vehicle NH3 emissions in the inventory. Measurements also indicated the urban atmosphere was NH3 rich for the formation of ammonium sulphate ((NH4)2SO4) particulate was SO2 limited while the formation of ammonium nitrate (NH4NO3) was NH3 limited. Any reduction in NOx emissions with improved catalytic converter efficiency will be accompanied by an increase in NH3 production and potentially with an increase in NH4NO3 particulate. [ABSTRACT FROM AUTHOR]