scholarly journals Climate-driven ground-level ozone extreme in the fall over the Southeast United States

2016 ◽  
Vol 113 (36) ◽  
pp. 10025-10030 ◽  
Author(s):  
Yuzhong Zhang ◽  
Yuhang Wang
Keyword(s):  
United States ◽  
Climate Models ◽  
Weather Condition ◽  
Ground Level ◽  
Field Studies ◽  
The United States ◽  
Fire Emissions ◽  
Ground Level Ozone ◽  
Ozone Concentrations ◽  
Ozone Precursor

Ground-level ozone is adverse to human and vegetation health. High ground-level ozone concentrations usually occur over the United States in the summer, often referred to as the ozone season. However, observed monthly mean ozone concentrations in the southeastern United States were higher in October than July in 2010. The October ozone average in 2010 reached that of July in the past three decades (1980–2010). Our analysis shows that this extreme October ozone in 2010 over the Southeast is due in part to a dry and warm weather condition, which enhances photochemical production, air stagnation, and fire emissions. Observational evidence and modeling analysis also indicate that another significant contributor is enhanced emissions of biogenic isoprene, a major ozone precursor, from water-stressed plants under a dry and warm condition. The latter finding is corroborated by recent laboratory and field studies. This climate-induced biogenic control also explains the puzzling fact that the two extremes of high October ozone both occurred in the 2000s when anthropogenic emissions were lower than the 1980s and 1990s, in contrast to the observed decreasing trend of July ozone in the region. The occurrences of a drying and warming fall, projected by climate models, will likely lead to more active photochemistry, enhanced biogenic isoprene and fire emissions, an extension of the ozone season from summer to fall, and an increase of secondary organic aerosols in the Southeast, posing challenges to regional air quality management.

Coal

2020 ◽  
pp. 81-119
Author(s):  
Paul F. Meier
Keyword(s):  
United States ◽  
Coal Combustion ◽  
Electricity Generation ◽  
Ground Level ◽  
The United States ◽  
Pulverized Coal ◽  
Ground Level Ozone ◽  
Energy Applications ◽  
Residential Heating ◽  
Coal Technology

Coal has two main energy applications, with about 90% used for electricity generation and 10% used for commercial and residential heating. In terms of electricity generation in the United States, coal is responsible for about 28%, a significant decrease from 53% twenty years earlier when it was the leading energy for producing electricity. There are two primary commercial methods for generating electricity from coal including pulverized coal combustion and fluidized bed coal combustion. To safely burn coal, sulfur, nitrogen, and heavy metals are removed at the electric plant. The sequestering of sulfur and nitrogen are important steps for limiting acid rain and ground level ozone. To generate electricity, the United States has about 360 coal plants with about 790 generators, of which greater than 90% use pulverized coal technology. Most coal is transported by rail.

scholarly journals Ontario Medical Association Position Paper on Health Effects of Ground-Level Ozone, Acid Aerosols and Particulate Matter

1998 ◽  
Vol 5 (5) ◽  
pp. 367-384 ◽  
Author(s):  
BT Boadway ◽  
J MacPhail ◽  
C Jacobson
Keyword(s):  
United States ◽  
Air Pollution ◽  
Nitrogen Oxides ◽  
Health Effects ◽  
Sulphur Dioxide ◽  
Air Pollutants ◽  
Ground Level ◽  
The United States ◽  
Ground Level Ozone ◽  
Emission Limits

This review of the evidence of the health effects of air pollutants focuses on research conducted in Ontario. Seven key Ontario studies are cited. These findings are highly significant for people living in the Great Lakes basin (and particularly the Windsor-Quebec corridor), where high levels of certain air pollutants (eg, ground-level ozone and ultra-fine particles) occur more frequently than in other parts of Canada. The issue is a serious one, requiring an integrated and comprehensive approach by many stakeholders, including the active involvement of organized medicine. It is important that the health effects of these air pollutants are understood. Governments must act to reduce emission levels through statue and regulation bolstered by noncompliance penalties.The findings of research have included the following: in a Toronto study, a 2% to 4% excess of respiratory deaths were attributable to pollutant levels; children living in rural Ontario communities with the highest levels of airborne acids were significantly more likely to report at least one episode of bronchitis, as well as to show decreases in lung function; and have been linked to increases in pollutants, emergency room visits and hospitalizations in Ontario.Every Ontarian is affected by air pollutants, although he or she may be unaware of the asymptomatic effects such as lung and bronchial inflammation. This health problem is preventable; while physicians know of the adverse health impacts of air pollution and they are concerned, individually they now focus on the treatment of symptoms. The major recommendations of the report are as follows:* Enactment of more stringent sulphur and nitrogen oxide emission limits, including a provincewide sulphur dioxide reduction of 75% from current cap levels, and the maximum allowable nitrogen oxides emission limits of 6000 tonnes annually from Ontario Hydro.* New transportation sector emission limits that should include California-level standards for light and heavy duty vehicles, reductions from off-road engines, an expanded vehicle inspection and maintenance program, and tougher standards for sulphur-in-fuel content.* Petitioning the United States Environmental Protection Agency administrator under Section 115 of the United States Clear Air Act to require reductions in the American emission of sulphur dioxide and nitrogen oxides, which damage the health of Canadian residents and their environment.* Physician advice to patients about the risks of smog exposure, physician support for more health effects research on air pollution, and physician promotion of the development of air pollution-related health education materials.The recommendations discussed in this paper will, if acted upon, lead to a significant reduction in the overall burden of illness from air pollutants, especially in children and the elderly. These recommendations have been selected from a review of recommendations made by various authorities, and are those that the OMA feels a particular responsibility to support.

scholarly journals Baseline levels and trends of ground level ozone in Canada and the United States

2010 ◽  
Vol 10 (18) ◽  
pp. 8629-8647 ◽  
Author(s):  
E. Chan ◽  
R. J. Vet
Keyword(s):  
United States ◽  
Ground Level ◽  
Western Canada ◽  
Eastern Canada ◽  
Ground Level Ozone ◽  
Mixing Ratios ◽  
Western Us ◽  
The Us ◽  
Baseline Levels ◽  
Ozone Precursor

Abstract. A statistical method was developed to extract baseline levels of ground level ozone in Canada and the US, and to quantify the temporal changes of baseline ozone levels on annual, seasonal, diurnal and decadal scales for the period 1997 to 2006 based on ground-level observations from 97 non-urban monitoring sites. Baseline ozone is defined here as ozone measured at a given site in the absence of strong local influences. The quantification of baseline levels involved using a Principal Component Analyses (PCA) to derive groups of commonly-varying sites in contiguous regions by season, followed by using backward air parcel trajectories to systematically select ozone mixing ratios associated with the baseline condition in each of the PCA-derived regions. Decadal trends were estimated by season for each of the regions using a generalized linear mixed model (GLMM). Baseline ozone mixing ratios determined by this method were found to vary geographically and seasonally. For the 1997–2006 period, baseline mixing ratios were calculated for annual and seasonal periods in seven regions of North America based on multi-site multi-year averages of the baseline data sets. The annual average (±1 standard deviation) baseline mixing ratios for the regions are as follows: Continental Eastern Canada=30±9 ppb, Continental Eastern US=30±10 ppb, Coastal Eastern Canada=27±9 ppb, Coastal Western Canada=19±10 ppb; Coastal Western US=39±10 ppb, Continental Western Canada=28±10 ppb and Continental Western US=46±7 ppb. Trends in the baseline mixing ratios were also found to vary by season and by geographical region. On a decadal scale, increasing baseline ozone trends (temperature-adjusted) were observed in all seasons along the Pacific coasts of Canada and the US, although the trends in California were not statistically significant. In the coastal zone of Pacific Canada, positive trends were found with a rate of increase of 0.28±0.26, 0.72±0.55, and 0.93±0.41 ppb/a in spring (MAM), summer (JJA) and winter (DJF), respectively. In the Atlantic coastal region, the trends were also positive in 3 of the 4 seasons (but only significantly so in MAM). In the high ozone precursor emission areas of the Eastern United States, decadal trends in baseline ozone are, in general, negative in the spring, summer and fall and appear to be controlled by the strong within-region changes induced by decreasing ozone precursor emissions.

scholarly journals An analysis of ozone damage to historical maize and soybean yields in the United States

2015 ◽  
Vol 112 (46) ◽  
pp. 14390-14395 ◽  
Author(s):  
Justin M. McGrath ◽  
Amy M. Betzelberger ◽  
Shaowen Wang ◽  
Eric Shook ◽  
Xin-Guang Zhu ◽  
...  
Keyword(s):  
United States ◽  
Food Production ◽  
Yield Loss ◽  
Cost Benefit ◽  
Ground Level ◽  
The United States ◽  
Yield Losses ◽  
Ground Level Ozone ◽  
Food And Feed ◽  
Actual Yield

Numerous controlled experiments find that elevated ground-level ozone concentrations ([O3]) damage crops and reduce yield. There have been no estimates of the actual yield losses in the field in the United States from [O3], even though such estimates would be valuable for projections of future food production and for cost–benefit analyses of reducing ground-level [O3]. Regression analysis of historical yield, climate, and [O3] data for the United States were used to determine the loss of production due to O3 for maize (Zea mays) and soybean (Glycine max) from 1980 to 2011, showing that over that period production of rain-fed fields of soybean and maize were reduced by roughly 5% and 10%, respectively, costing approximately $9 billion annually. Maize, thought to be inherently resistant to O3, was at least as sensitive as soybean to O3 damage. Overcoming this yield loss with improved emission controls or more tolerant germplasm could substantially increase world food and feed supply at a time when a global yield jump is urgently needed.

scholarly journals Ambient air pollutants and their effect on COVID-19 mortality in the United States of America

2020 ◽  
Vol 44 ◽  
pp. 1
Author(s):  
Samuel Liu ◽  
Meng Li
Keyword(s):  
United States ◽  
Nitrogen Dioxide ◽  
Air Pollutants ◽  
Ground Level ◽  
Ambient Air ◽  
The United States ◽  
Mortality Rates ◽  
County Level ◽  
Ground Level Ozone ◽  
Ambient Air Pollutants

Objective. To examine the impact of four ambient air pollutants on the COVID-19 mortality rate in the United States of America. Methods. Using publicly accessible data collected by the United States Census Bureau, Environmental Protection Agency, and other agencies, county-level mortality rates were regressed on concentration values of ground-level ozone, nitrogen dioxide, carbon monoxide, and sulfur dioxide. Four confounder variables were included in the regression analysis: median household income, rate of hospital beds, population density, and days since first confirmed case. Results. Regression analysis showed that ground-level ozone is positively correlated with county-level mortality rates regardless of whether confounders are controlled for. Nitrogen dioxide is also shown to have a direct relationship with county-level mortality rates, except when all confounders are included in the analysis. Conclusions. High ground-level ozone and nitrogen dioxide concentrations contribute to a greater COVID-19 mortality rate. To limit further losses, it is important to reflect research findings in public policies. In the case of air pollution, environmental restrictions should be reinforced, and extra precautions should be taken as facilities start reopening.

Considerations on Ambient Levels of Ozone Concentrations and Relationship with NOx in an Urban Environment

2017 ◽  
Vol 68 (4) ◽  
pp. 824-829
Author(s):  
Cornel Ianache ◽  
Laurentiu Predescu ◽  
Mirela Predescu ◽  
Dumitru Dumitru
Keyword(s):  
Nitrogen Oxides ◽  
Urban Areas ◽  
Road Traffic ◽  
Temporal Distribution ◽  
Ground Level ◽  
Distinct Pattern ◽  
Weekend Effect ◽  
Monitoring Site ◽  
Ground Level Ozone ◽  
Ozone Concentrations

The serious air pollution problem has determined public concerns, worldwide. One of the main challenges for countries all over the world is caused by the elevated levels of ground-level ozone (O3) concentrations and its anthropogenic precursors. Ploiesti city, as one of the major urban area of Romania, is facing the same situation. This research aims to investigate spatial and temporal distribution characteristics of O3 in relationship with nitrogen oxides (NOx) using statistical analysis methods. Hourly O3 and NOx measurements were collected during 2014 year in Ploiesti. The results obtained showed that the ozone spatial distribution was non-normal for each month in 2014. The diurnal cycle of ground-level ozone concentrations showed a mid-day peak, while NOx diurnal variations presented 2 daily peaks, one in the morning (7:00 a.m.) and one in the afternoon (between 5:00 and 7:00 p.m.). In addition, it was observed a distinct pattern of weekly variations for O3 and NOx. Like in many other urban areas, the results indicated the presence of the �ozone weekend effect� in Ploiesti during the 2014 year, ozone concentrations being slightly higher on weekends compared to weekdays. For the same monitoring site, the nitrogen oxides were less prevalent on Saturdays and Sundays, probably due to reducing of road traffic and other pollution-generating activities on weekends than during the week.

scholarly journals Spatial–Temporal Distribution Variation of Ground-Level Ozone in China’s Pearl River Delta Metropolitan Region

2021 ◽  
Vol 18 (3) ◽  
pp. 872
Author(s):  
An Zhang ◽  
Jinhuang Lin ◽  
Wenhui Chen ◽  
Mingshui Lin ◽  
Chengcheng Lei
Keyword(s):  
Ozone Concentration ◽  
Pearl River Delta ◽  
Temporal Distribution ◽  
Ground Level ◽  
Metropolitan Region ◽  
Pearl River ◽  
Ozone Pollution ◽  
Ground Level Ozone ◽  
Ozone Concentrations ◽  
The North

Long-term exposure to ozone pollution will cause severe threats to residents’ physical and mental health. Ground-level ozone is the most severe air pollutant in China’s Pearl River Delta Metropolitan Region (PRD). It is of great significance to accurately reveal the spatial–temporal distribution characteristics of ozone pollution exposure patterns. We used the daily maximum 8-h ozone concentration data from PRD’s 55 air quality monitoring stations in 2015 as input data. We used six models of STK and ordinary kriging (OK) for the simulation of ozone concentration. Then we chose a better ozone pollution prediction model to reveal the ozone exposure characteristics of the PRD in 2015. The results show that the Bilonick model (BM) model had the highest simulation precision for ozone in the six models for spatial–temporal kriging (STK) interpolation, and the STK model’s simulation prediction results are significantly better than the OK model. The annual average ozone concentrations in the PRD during 2015 showed a high spatial variation in the north and east and low in the south and west. Ozone concentrations were relatively high in summer and autumn and low in winter and spring. The center of gravity of ozone concentrations tended to migrate to the north and west before moving to the south and then finally migrating to the east. The ozone’s spatial autocorrelation was significant and showed a significant positive correlation, mainly showing high-high clustering and low-low clustering. The type of clustering undergoes temporal migration and conversion over the four seasons, with spatial autocorrelation during winter the most significant.

Assess 21st century Flash Drought in the United States using high resolution regional climate models

2021 ◽  
Author(s):  
Brandi Gamelin ◽  
Jiali Wang ◽  
V. Rao Kotamarthi
Keyword(s):  
Climate Change ◽  
United States ◽  
Soil Moisture ◽  
Climate Models ◽  
Wrf Model ◽  
The United States ◽  
Future Climate Change ◽  
Climate Change Scenarios ◽  
Regional Variability ◽  
Groundwater Levels

<p>Flash droughts are the rapid intensification of drought conditions generally associated with increased temperatures and decreased precipitation on short time scales.  Consequently, flash droughts are responsible for reduced soil moisture which contributes to diminished agricultural yields and lower groundwater levels. Drought management, especially flash drought in the United States is vital to address the human and economic impact of crop loss, diminished water resources and increased wildfire risk. In previous research, climate change scenarios show increased growing season (i.e. frost-free days) and drying in soil moisture over most of the United States by 2100. Understanding projected flash drought is important to assess regional variability, frequency and intensity of flash droughts under future climate change scenarios. Data for this work was produced with the Weather Research and Forecasting (WRF) model. Initial and boundary conditions for the model were supplied by CCSM4, GFDL-ESM2G, and HadGEM2-ES and based on the 8.5 Representative Concentration Pathway (RCP8.5). The WRF model was downscaled to a 12 km spatial resolution for three climate time frames: 1995-2004 (Historical), 2045-2054 (Mid), and 2085-2094 (Late).  A key characteristic of flash drought is the rapid onset and intensification of dry conditions. For this, we identify onset with vapor pressure deficit during each time frame. Known flash drought cases during the Historical run are identified and compared to flash droughts in the Mid and Late 21<sup>st</sup> century.</p>

Sign in / Sign up

Export Citation Format

Share Document