scholarly journals Air quality in the eastern United States and Eastern Canada for 1990–2015: 25 years of change in response to emission reductions of SO<sub>2</sub> and NO<sub>x</sub> in the region

2019 ◽  
Author(s):  
Jian Feng ◽  
Elton Chan ◽  
Robert Vet
Keyword(s):  
Air Quality ◽  
Warm Season ◽  
Monitoring Network ◽  
Cold Season ◽  
Eastern United States ◽  
Eastern Canada ◽  
Spatial Changes ◽  
The Us ◽  
Clean Air ◽  
Uniform Reduction

Abstract. SO2 and NOx are precursors to form sulfate, nitrate and ammonium particles, which account for more than 50 % of PM2.5 mass in the eastern US and Eastern Canada, and are dominant components of PM2.5 during many smog events. H2SO4 and HNO3, formed from oxidation of SO2 and NOx respectively, are the main sources of acid deposition through wet and dry depositions. NOx is also a precursor to the formation of tropospheric O3, which is an important atmospheric oxidant and is also essential for the formation of other atmospheric oxidants, such as OH and H2O2. In the past 26 years from 1990 to 2015, emissions of SO2 and NOx in US were significantly reduced from 23.1 and 25.2 million tons/year in 1990 to 3.7 and 11.5 million tons/year in 2015 respectively. In Canada, SO2 and NOx were reduced by 63 % and 33 % from 1990 to 2014. In response to the significant reduction of SO2 and NOx emissions, air quality in the eastern US and Eastern Canada improved tremendously during 1990–2015. In this study, we analyzed surface air concentrations of SO42−, NO3−, NH4+, HNO3 and SO2 measured weekly by the Clean Air Status and Trends Network (CASTNET) in the US and measured daily from the Canadian Air and Precipitation Monitoring Network (CAPMoN) in Canada to reveal the temporal and spatial changes of each species during the 25-year period. For the whole the eastern US and Eastern Canada, the annual mean concentrations of SO42−, NO3−, NH4+, HNO3, SO2 and TNO3 (NO3− + HNO3, expressed as the mass of equivalent NO3−) were reduced by 73.3 %, 29.1 %, 67.4 %, 65.8 %, 87.6 % and 52.6 % respectively from 1990 to 2015. In terms of percentage, reduction of all species except NO3− was spatially uniform; reduction of SO2 and HNO3 was similar in warm season (May–October) and cold season (November–April), and reduction of SO42−, NO3− and NH4+ was more significant in warm season than in cold season. Reduction of SO42− and SO2 mainly occurred in 1989–1995 and 2007–2015 during warm season, and in 1989–1995 and 2005–2015 during cold season. Reduction of NO3− mainly occurred in the Midwest after 2000. Other than in the Midwest, NO3− had very little change during cold season for the period. The reduction of NH4+ generally followed the reduction trend of SO42−, especially after 2000 the temporal trend of NH4+ was almost identical to that of SO42−. The ratio of S in SO42− to total S in SO42− and SO2, as well as the ratio of NO3− to TNO3 increased by more than 50 % during the period. This indicates that much more percentage of SO2 was oxidized to SO42−, and much more percentage of HNO3 was neutralized to NH4NO3 in the region near the end of the period.

scholarly journals Air quality in the eastern United States and Eastern Canada for 1990–2015: 25 years of change in response to emission reductions of SO<sub>2</sub> and NO<sub><i>x</i></sub> in the region

2020 ◽  
Vol 20 (5) ◽  
pp. 3107-3134 ◽  
Author(s):  
Jian Feng ◽  
Elton Chan ◽  
Robert Vet
Keyword(s):  
Air Quality ◽  
Warm Season ◽  
Monitoring Network ◽  
Cold Season ◽  
Eastern United States ◽  
Eastern Canada ◽  
Spatial Changes ◽  
The Us ◽  
Clean Air ◽  
Temporal And Spatial

Abstract. SO2 and NOx are precursors to form sulfate, nitrate, and ammonium particles in the air, which account for more than 50 % of PM2.5 mass in the eastern US (Bell et al., 2007) and are dominant components of PM2.5 during many smog events (Dabek-Zlotorzynska et al., 2011). H2SO4 and HNO3, formed from the oxidation of SO2 and NOx, respectively, are the main sources of acid deposition through wet and dry depositions. NOx is also a precursor to the formation of tropospheric O3, which is an important atmospheric oxidant and is also essential for the formation of other atmospheric oxidants, such as OH and H2O2. In the past 26 years from 1990 to 2015, emissions of SO2 and NOx in the US were significantly reduced from 23.1 and 25.2 million t yr−1 in 1990 to 3.7 and 11.5 million t yr−1 in 2015, respectively. In Canada, SO2 and NOx were reduced by 63 % and 33 % from 1990 to 2014. In response to the significant reductions of SO2 and NOx emissions, air quality in the eastern US and Eastern Canada improved tremendously during 1990–2015. In this study, we analyzed surface air concentrations of SO42-, NO3-, NH4+, HNO3, and SO2 measured weekly by the Clean Air Status and Trends Network (CASTNET) in the US and measured daily from the Canadian Air and Precipitation Monitoring Network (CAPMoN) in Canada to reveal the temporal and spatial changes in each species during the 25-year period. For the whole eastern US and Eastern Canada, the annual mean concentrations of SO42-, NO3-, NH4+, HNO3, SO2, and TNO3 (NO3- + HNO3, expressed as the mass of equivalent NO3-) were reduced by 73.3 %, 29.1 %, 67.4 %, 65.8 %, 87.6 %, and 52.6 %, respectively, from 1990 to 2015. In terms of percentage, the reductions of all species except NO3- were spatially uniform. The reductions of SO2 and HNO3 were similar in the warm season (May–October) and the cold season (November–April), and the reductions of SO42-, NO3-, and NH4+ were more significant in the warm season than in the cold season. The reductions of SO42- and SO2 mainly occurred in 1990–1995 and 2007–2015 during the warm season and in 1990–1995 and 2005–2015 during the cold season. The reduction of NO3- mainly occurred in the Midwest after 2000. Other than in the Midwest, NO3- exhibited very little change during the cold season for the period. The reduction of NH4+ generally followed the reduction trend of SO42-; especially after 2000, the temporal trend of NH4+ was almost identical to that of SO42-. The ratio of S in SO42- to total S in SO42- plus SO2, as well as the ratio of NO3- to TNO3 increased by more than 50 % during the period. This indicates that a notable change in regional chemistry took place from the beginning to the end of the period, with a higher percentage of SO2 being oxidized to SO42- and a higher percentage of HNO3 being neutralized to NH4NO3 near the end of the period.

scholarly journals The Unintended Disincentive in the Clean Air Act

2004 ◽  
Vol 3 (2) ◽  
Author(s):  
John A. List ◽  
Daniel L Millimet ◽  
Warren McHone
Keyword(s):  
Air Quality ◽  
Empirical Evidence ◽  
Clean Air Act ◽  
The Us ◽  
Entire Plant ◽  
Clean Air ◽  
Plant Level ◽  
Current Standards

Abstract The Clean Air Act and its subsequent amendments have been lauded as the primary stimulant to the impressive improvement in local air quality in the US since 1970. A key component of these regulations is the New Source Review (NSR) requirement, which includes the contentious stipulation that when an existing plant seeks to modify its operations, the entire plant must comply with current standards for new sources. This requirement was included to improve air quality in dirty areas, and prevent a deterioration of air quality in clean areas. Yet, whether NSR provides the proper plant-level incentives is unclear: there are strong disincentives to undertake major plant modifications to avoid NSR. In our examination of more than 2500 and 2200 plant-level modification decisions and closures, respectively, we find empirical evidence suggesting that NSR retards modification rates, while doing little to hasten the closure of existing dirty plants.

scholarly journals Establishing a Community Air Monitoring Network in a Wildfire Smoke-Prone Rural Community: The Motivations, Experiences, Challenges, and Ideas of Clean Air Methow’s Clean Air Ambassadors

2020 ◽  
Vol 17 (22) ◽  
pp. 8393
Author(s):  
Amanda Durkin ◽  
Rico Gonzalez ◽  
Tania Busch Isaksen ◽  
Elizabeth Walker ◽  
Nicole A. Errett
Keyword(s):  
Air Quality ◽  
Environmental Science ◽  
Low Cost ◽  
Geographic Location ◽  
Monitoring Network ◽  
Air Monitoring ◽  
Wildfire Smoke ◽  
Clean Air ◽  
Quality Issues ◽  
Future Project

In response to wildfire-related air quality issues as well as those associated with winter wood stove use and prescribed and agricultural burning, Clean Air Methow’s Clean Air Ambassador program established a community air monitoring network (CAMN) to provide geospatially specific air quality information and supplement data generated by the two Washington State Department of Ecology nephelometers situated in the area. Clean Air Ambassadors (CAAs) were purposefully selected to host low-cost air sensors based on their geographic location and interest in air quality. All 18 CAAs were interviewed to understand their motivations for participation, experiences using the data, challenges encountered, and recommendations for future project directions. Interview transcripts were coded, and a qualitative analysis approach was used to identify the key themes in each domain. The reported motivations for participation as a CAA included reducing personal exposure, protecting sensitive populations, interest in air quality or environmental science, and providing community benefits. CAAs used CAMN data to understand air quality conditions, minimize personal or familial exposure, and engage other community members in air quality discussions. Opportunities for future project directions included use for monitoring other seasonal air quality issues, informing or reducing other pollution-generating activities, school and community educational activities, opportunities for use by and engagement of different stakeholder groups, and mobile-friendly access to CAMN information. Limited challenges associated with participation were reported. Additional research is necessary to understand the community-level impacts of the CAMN. The findings may be informative for other rural wildfire smoke-prone communities establishing similar CAMNs.

scholarly journals Recent Genotypes of Phytophthora infestans in the Eastern United States Reveal Clonal Populations and Reappearance of Mefenoxam Sensitivity

Plant Disease ◽  
2012 ◽  
Vol 96 (9) ◽  
pp. 1323-1330 ◽  
Author(s):  
Chia-Hui Hu ◽  
Frances G. Perez ◽  
Ryan Donahoo ◽  
Adele McLeod ◽  
Kevin Myers ◽  
...  
Keyword(s):  
United States ◽  
New York ◽  
North Carolina ◽  
Phytophthora Infestans ◽  
Eastern United States ◽  
Ras Gene ◽  
Eastern Canada ◽  
Commercial Potato ◽  
Close Proximity ◽  
The Us

Isolates of Phytophthora infestans (n = 178) were collected in 2002 to 2009 from the eastern United States, Midwestern United States, and eastern Canada. Multilocus genotypes were defined using allozyme genotyping, and DNA fingerprinting with the RG-57 probe. Several previously described and three new mulitilocus genotypes were detected. The US-8 genotype was found commonly on commercial potato crops but not on tomato. US-20 was found on tomato in North Carolina from 2002 through 2007 and in Florida in 2005. US-21 was found on tomato in North Carolina in 2005 and Florida in 2006 and 2007. US-22 was detected on tomato in 2007 in Tennessee and New York and became widespread in 2009. US-22 was found in 12 states on tomato and potato and was spread on tomato transplants. This genotype accounted for about 60% of all the isolates genotyped. The US-23 genotype was found in Maryland, Virginia, Pennsylvania, and Delaware on both tomato and potato in 2009. The US-24 genotype was found only in North Dakota in 2009. A1 and A2 mating types were found in close proximity on potato and tomato crops in Pennsylvania and Virginia; therefore, the possibility of sexual reproduction should be monitored. Whereas most individuals of US-8 and US-20 were resistant to mefenoxam, US-21 appeared to be intermediately sensitive, and isolates of US-22, US-23, and US-24 were largely sensitive to mefenoxam. On the basis of sequence analysis of the ras gene, these latter three genotypes appear to have been derived from a common ancestor. Further field and laboratory studies are underway using simple sequence repeat genotyping to monitor current changes in the population structure of P. infestans causing late blight in North America.

scholarly journals Projecting wildfire emissions over the south-eastern United States to mid-century

2018 ◽  
Vol 27 (5) ◽  
pp. 313 ◽  
Author(s):  
Uma Shankar ◽  
Jeffrey P. Prestemon ◽  
Donald McKenzie ◽  
Kevin Talgo ◽  
Aijun Xiu ◽  
...  
Keyword(s):  
United States ◽  
Air Quality ◽  
Socioeconomic Factors ◽  
Dynamical Downscaling ◽  
Climate Projections ◽  
Particulate Emissions ◽  
Eastern United States ◽  
The South ◽  
South Eastern ◽  
The Us

Wildfires can impair human health because of the toxicity of emitted pollutants, and threaten communities, structures and the integrity of ecosystems sensitive to disturbance. Climate and socioeconomic factors (e.g. population and income growth) are known regional drivers of wildfires. Reflecting changes in these factors in wildfire emissions estimates is thus a critical need in air quality and health risk assessments in the south-eastern United States. We developed such a methodology leveraging published statistical models of annual area burned (AAB) over the US Southeast for 2011–2060, based on county-level socioeconomic and climate projections, to estimate daily wildfire emissions in selected historical and future years. Projected AABs were 7 to 150% lower on average than the historical mean AABs for 1992–2010; projected wildfire fine-particulate emissions were 13 to 62% lower than those based on historical AABs, with a temporal variability driven by the climate system. The greatest differences were in areas of large wildfire impacts from socioeconomic factors, suggesting that historically based (static) wildfire inventories cannot properly represent future air quality responses to changes in these factors. The results also underscore the need to correct biases in the dynamical downscaling of wildfire climate drivers to project the health risks of wildfire emissions more reliably.

scholarly journals EVALUATION OF LITHUANIAN AIR QUALITY MONITORING DATA APPLYING SYNOPTICAL ANALYSIS

2007 ◽  
Vol 15 (3) ◽  
pp. 173-181 ◽  
Author(s):  
Vilma Bimbaitė ◽  
Raselė Girgždienė
Keyword(s):  
Air Quality ◽  
Ozone Concentration ◽  
Warm Season ◽  
Cold Season ◽  
Quality Monitoring ◽  
Monitoring Data ◽  
Air Quality Monitoring ◽  
Ozone Level ◽  
Ozone Concentrations ◽  
Ozone Levels

Relationship between synoptical patterns and different pollutants was analysed in the study. Cases with ozone concentrations higher or equal to the 95th percentile of monthly ozone concentrations were analysed over the period 2002–2005. Ozone concentration cases were grouped into seven concentration intervals and analysed according to synoptical patterns (cold, warm and occluded fronts). Relationship between SO2, SO4 and NO2 and synoptical objects was analysed during warm and cold seasons. The influence of cold, warm and occluded fronts on the high ozone level formation are very similar at both Lithuanian rural stations of Preila and Rūgšteliškes. The influence of all the fronts was more significant during night hours at a relatively low (50–100 μg/m3) and high (>100 μg/m3) ozone levels during day hours. The concentrations of gaseous SO2, NO2 and aerosol SO4 pollutants for the cases with hourly ozone concentration values ≥95th percentile were analysed. The influence of different synoptical patterns was found to be stronger during a warm season and lower during a cold season of the year.

scholarly journals Analysis of Changes in the Concentration of Carbon Dioxide in Indoor Air of a Sports University

2021 ◽  
pp. 22-27
Author(s):  
NKh Davletova ◽  
EA Tafeeva
Keyword(s):  
Carbon Dioxide ◽  
Air Quality ◽  
Warm Season ◽  
Co2 Concentration ◽  
Cold Season ◽  
Permissible Limit ◽  
Standard Samples ◽  
Co2 Concentrations ◽  
School Day ◽  
The University

Introduction: Air quality of the premises of a sports university determines comfort and effectiveness of the educational and training processes and can be considered as a risk factor for students’ health. The purpose of our study was to give a hygienic assessment of changes in the indoor CO2 concentration at a sports university during the school day. Materials and methods: Air quality measurements were taken in twelve classrooms, six lecture halls, three sports halls, and a gym. The subjective assessment of air quality in classrooms was analyzed using data of a questionnaire-based survey of 651 students. Results: We found that differences in the proportion of air samples with elevated CO2 concentrations between the rooms were insignificant and ranged from 32 ± 4.66 % to 41.33 ± 2.84 % in the cold season (CS) and from 42.33 ± 2.85 % to 49.33 ± 4.08 % in the warm season (WS). Average CO2 concentrations in non-standard samples were 1,132.11 ± 93.21 ppm and 1,124.98 ± 98.51 ppm in the cold and warm season, respectively. We established that in the cold season, indoor CO2 concentration exceeded the permissible limit in 100 % of the classrooms, 50 % of the lecture halls and the gym already by 3.40 p.m. (15:40); by the end of the school day, the excess was registered in 100 % of the university rooms. In the warm season, CO2 concentrations were above the limit in the gym and in 33.3% of the lecture halls by 1 p.m. (13:00), and by 3.40 p.m. the excess was observed in 100 % of the rooms examined. Subjective air quality assessments indicated that most students often complained about stuffiness in classrooms; 25.25 ± 1.2 % of the respondents mentioned a strong odor in sports halls and the gym. Conclusion: In a significant part of sports university rooms, CO2 concentrations did not exceed permissible values for more than 80 % of school hours. Yet, after the fourth double lesson, this air quality indicator went beyond the standard value, and by the end of the school day indoor concentrations of carbon dioxide were above the permissible limit in 100 % of the university rooms.

scholarly journals Air Quality in Windsor (Canada) and Impact of Regional Scale Transport

Atmosphere ◽  
2021 ◽  
Vol 12 (10) ◽  
pp. 1300
Author(s):  
Tianchu Zhang ◽  
Yangfan Chen ◽  
Rongtai Tan ◽  
Xiaohong Xu
Keyword(s):  
Air Quality ◽  
Regional Scale ◽  
Warm Season ◽  
Cold Season ◽  
Control Measures ◽  
Effective Control ◽  
Risk Level ◽  
Small Contribution ◽  
Air Masses ◽  
The Impact

Air Quality Health Index (AQHI) is a scale designed in Canada to help residences understand the impact of air quality on health. This study investigated temporal variability of daily AQHI and impact of regional transport on AQHI in Windsor, Ontario, Canada from 2016 to 2019. The four-year average daily AQHI was 2.9, slightly below the upper limit of the low health risk level of 3. AQHI value decreased from 2.95 to 2.81 during the study period, indicating the improvement of air quality. Half of the days, AQHI were 3 regardless of season. AQHI was higher in the warm season (3.1) than in the cold season (2.6) due to more frequent moderate risk days (27%, AQHI = 4) in warm season and more frequent low risk days (42%, AQHI = 2) in the cold season. Among the three pollutants considered, O3 was the most frequently reported dominant contributor to daily AQHI (88% of days), followed by NO2 (12%), especially in the cold season, with small contribution from PM2.5 (<1%). Trajectory analysis found that AQHI ≤ 3 days were closely associated with air masses from the north and northwest, whereas AQHI > 3 days were closely associated with air masses from the west and southwest. This is because northerly flows brought in clear air mass owing to less industrial facilities. Polluted air masses were transported from the south of Windsor, where several industrial states of the US were located. Directional AQHI resembles O3 more than NO2 or PM2.5 concentrations do. Further improvement of AQHI in Windsor could be challenging because O3 concentrations have continued to increase in recent years. Thus, more effective control measures to mitigate O3 pollution are warranted to reduce its impact on human health and the environment.

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