Tropospheric pollutants including surface ozone（O3）, nitrogen dioxide（NO2）, carbon monoxide（CO） and meteorological parameters were measured at a traffic junction（78°2′ E and 27°11′ N） in Agra, Indi...Tropospheric pollutants including surface ozone（O3）, nitrogen dioxide（NO2）, carbon monoxide（CO） and meteorological parameters were measured at a traffic junction（78°2′ E and 27°11′ N） in Agra, India from January 2012 to December 2012. Temporal analysis of pollutants suggests that annual average mixing ratios of tropospheric pollutants were： O3— 22.97 ± 23.36 ppbV,NO2— 19.84 ± 16.71 ppb V and CO — 0.91 ± 0.86 ppm V, with seasonal variations of O3 having maximum mixing ratio during summer season（32.41 ± 19.31 ppbV）, whereas lowest was found in post-monsoon season（8.74 ± 3.8 ppbV）. O3 precursors： NO2 and CO, showed inverse relationship with O3. Seasonal variation and high O3 episodes during summer are associated with meteorological parameters such as high solar radiation, atmospheric temperature and transboundary transport. The interdependence of these variables showed a link between the daytime mixing ratios of O3 with the nighttime level of NO2. The mixing ratios of CO and NO2 showed tight correlations, which confirms the influence of vehicular emissions combined with other anthropogenic activities due to office/working hours, shallowing, and widening of boundary layer. FLEXTRA backward trajectories for the O3 episode days clearly indicate the transport from the NW and W to S/SE and SW direction at Agra in different seasons.展开更多
<span>The Houston-Galveston-Brazoria (HGB) area of Texas has historically experienced severe air pollution events with high concentrations of ozone (O</span><sub><span>3</span></sub>...<span>The Houston-Galveston-Brazoria (HGB) area of Texas has historically experienced severe air pollution events with high concentrations of ozone (O</span><sub><span>3</span></sub><span>) during the summer season. This study evaluates the contribution of different anthropogenic sources to ozone formation in the HGB area. The Emission Processing System (EPS3) is used to process emission files in four different scenarios (Base case as including All emission sources (BC), All sources— Area sources (AM</span><span><span><span>A</span></span></span><span><span><span style="font-family:;" "=""><span>), All sources—Point sources (AMP), and All sources— Mobile sources (AMM). These files are used as input in photochemical modeling with the Comprehensive Air Quality Model with Extensions (CAMx) to simulate ozone formation. The data is analyzed for daily maximum ozone </span><span>concentrations and contribution of source categories at three air quality </span><span>monitoring locations (La Porte Sylvan beach-C556, Houston Texas avenue-C411, and Texas city in Galveston-C683) for a study period of June 1</span></span></span></span><span><span><span>-</span></span></span><span><span><span style="font-family:;" "=""><span>June 30, 2012. The contribution of the point sources to ozone formation is dominated at all three locations, followed by mobile sources and area sources on high ozone days. The relative contributions of point sources are 27.51% ± </span><span>3.53%, 21.45% ± 7.36%, and 30.30% ± 9.36%;and mobile sources are 18.27%</span><span> ± 2.22%, 20.60% ± 6.89%, and 18.61% ± 7.43%;and area sources were 4.2% ± 1.65%, 5.21% ± 1.59%, and 3.72% ± 1.52% at C556, C411, and C683, respectively. These results demonstrate the importance of regulatory focus on controlling point and mobile source emissions for NAAQS attainment in the study region.</span></span></span></span>展开更多
Ground-level ozone is a harmful air pollutant associated with several health issues. Ozone concentrations have exceeded the National Ambient Air Quality Standards (NAAQS) in the Chicago metropolitan area on hot summer...Ground-level ozone is a harmful air pollutant associated with several health issues. Ozone concentrations have exceeded the National Ambient Air Quality Standards (NAAQS) in the Chicago metropolitan area on hot summer days for many years because of nitrogen oxide and volatile organic compound emissions. Annual fourth highest 8-hour ozone concentrations have been between 0.070 and 0.084 ppm at several monitoring sites in Cook county, during the 2016-2018 time period. The continuous measurement of nitrogen dioxide (NO<sub>2</sub>) and ozone (O<sub>3</sub>) was conducted in several communities in Chicago in 2017. The air pollution impacts the health of all who live in the area. The data were used to analyze correlations between the O<sub>3</sub> distribution and its association with ambient concentrations of NO<sub>2</sub> from transportation emissions. Higher concentrations in NO<sub>2</sub> and O<sub>3</sub> occurred in succession in the daytime. The diurnal variation of O<sub>3</sub> concentration was analyzed. The daily cycle of NO<sub>2</sub> concentration reaches a maximum in the late morning and has smaller nighttime concentrations. The daily cycle of ozone concentration reaches the maximum in the afternoon and also becomes smaller for nighttime concentrations. In addition, relationships were found between O<sub>3</sub> and NO<sub>2</sub>. Monthly variations of ozone and NO<sub>2</sub> are presented. Some options to reduce ozone pollution are presented.展开更多
基金the University Grant Commission(UGC)New Delhi for funding(Project No:F.15–45/12(SA–II))
文摘Tropospheric pollutants including surface ozone（O3）, nitrogen dioxide（NO2）, carbon monoxide（CO） and meteorological parameters were measured at a traffic junction（78°2′ E and 27°11′ N） in Agra, India from January 2012 to December 2012. Temporal analysis of pollutants suggests that annual average mixing ratios of tropospheric pollutants were： O3— 22.97 ± 23.36 ppbV,NO2— 19.84 ± 16.71 ppb V and CO — 0.91 ± 0.86 ppm V, with seasonal variations of O3 having maximum mixing ratio during summer season（32.41 ± 19.31 ppbV）, whereas lowest was found in post-monsoon season（8.74 ± 3.8 ppbV）. O3 precursors： NO2 and CO, showed inverse relationship with O3. Seasonal variation and high O3 episodes during summer are associated with meteorological parameters such as high solar radiation, atmospheric temperature and transboundary transport. The interdependence of these variables showed a link between the daytime mixing ratios of O3 with the nighttime level of NO2. The mixing ratios of CO and NO2 showed tight correlations, which confirms the influence of vehicular emissions combined with other anthropogenic activities due to office/working hours, shallowing, and widening of boundary layer. FLEXTRA backward trajectories for the O3 episode days clearly indicate the transport from the NW and W to S/SE and SW direction at Agra in different seasons.
文摘<span>The Houston-Galveston-Brazoria (HGB) area of Texas has historically experienced severe air pollution events with high concentrations of ozone (O</span><sub><span>3</span></sub><span>) during the summer season. This study evaluates the contribution of different anthropogenic sources to ozone formation in the HGB area. The Emission Processing System (EPS3) is used to process emission files in four different scenarios (Base case as including All emission sources (BC), All sources— Area sources (AM</span><span><span><span>A</span></span></span><span><span><span style="font-family:;" "=""><span>), All sources—Point sources (AMP), and All sources— Mobile sources (AMM). These files are used as input in photochemical modeling with the Comprehensive Air Quality Model with Extensions (CAMx) to simulate ozone formation. The data is analyzed for daily maximum ozone </span><span>concentrations and contribution of source categories at three air quality </span><span>monitoring locations (La Porte Sylvan beach-C556, Houston Texas avenue-C411, and Texas city in Galveston-C683) for a study period of June 1</span></span></span></span><span><span><span>-</span></span></span><span><span><span style="font-family:;" "=""><span>June 30, 2012. The contribution of the point sources to ozone formation is dominated at all three locations, followed by mobile sources and area sources on high ozone days. The relative contributions of point sources are 27.51% ± </span><span>3.53%, 21.45% ± 7.36%, and 30.30% ± 9.36%;and mobile sources are 18.27%</span><span> ± 2.22%, 20.60% ± 6.89%, and 18.61% ± 7.43%;and area sources were 4.2% ± 1.65%, 5.21% ± 1.59%, and 3.72% ± 1.52% at C556, C411, and C683, respectively. These results demonstrate the importance of regulatory focus on controlling point and mobile source emissions for NAAQS attainment in the study region.</span></span></span></span>
文摘Ground-level ozone is a harmful air pollutant associated with several health issues. Ozone concentrations have exceeded the National Ambient Air Quality Standards (NAAQS) in the Chicago metropolitan area on hot summer days for many years because of nitrogen oxide and volatile organic compound emissions. Annual fourth highest 8-hour ozone concentrations have been between 0.070 and 0.084 ppm at several monitoring sites in Cook county, during the 2016-2018 time period. The continuous measurement of nitrogen dioxide (NO<sub>2</sub>) and ozone (O<sub>3</sub>) was conducted in several communities in Chicago in 2017. The air pollution impacts the health of all who live in the area. The data were used to analyze correlations between the O<sub>3</sub> distribution and its association with ambient concentrations of NO<sub>2</sub> from transportation emissions. Higher concentrations in NO<sub>2</sub> and O<sub>3</sub> occurred in succession in the daytime. The diurnal variation of O<sub>3</sub> concentration was analyzed. The daily cycle of NO<sub>2</sub> concentration reaches a maximum in the late morning and has smaller nighttime concentrations. The daily cycle of ozone concentration reaches the maximum in the afternoon and also becomes smaller for nighttime concentrations. In addition, relationships were found between O<sub>3</sub> and NO<sub>2</sub>. Monthly variations of ozone and NO<sub>2</sub> are presented. Some options to reduce ozone pollution are presented.
