scholarly journals Observed changes in the temperature dependence response of surface ozone under NO<sub><i>x</i></sub> reductions

2020 ◽  
Author(s):  
Noelia Otero ◽  
Henning W. Rust ◽  
Tim Butler
Keyword(s):  
Temperature Dependence ◽  
Surface Ozone ◽  
Additive Models ◽  
Ozone Production ◽  
Temperature Relationship ◽  
Strong Temperature Dependence ◽  
Ozone Pollution ◽  
Production Rates ◽  
Penalty Factor ◽  
Second Period

Abstract. Due to the strong temperature dependence of surface ozone concentrations (O3), future warmer conditions may worsen ozone pollution levels despite continued efforts on emission controls of ozone precursors. Using long-term measurements of hourly O3 concentrations co-located with NOx concentrations in stations distributed throughout Germany, we assess changes in the climate penalty, defined as the slope of ozone-temperature relationship during the period 1999–2018. We find a stronger temperature sensitivity in the urban stations over the southwestern regions, especially in the first period of the study (1999–2008).We show a decrease in the climate penalty in most of stations during the second period of the study (2009–2018), with some exceptions (e.g. Berlin) where the climate penalty did not show significant changes. To examine the impacts of NOx reductions on the O3 sensitivity to temperature, we propose a statistical approach based on generalized additive models (GAMs) to describe ozone production rates, inferred from hourly observations, as a function of NOx and temperature, among other variables relevant during the O3 production. We find lower O3 production rates during the second period (2009–2018) at most stations and a decreasing sensitivity to temperature, pointing out that lowering NOx concentrations resulted in decreasing O3 production rates. However, we also observe changes in the shape of the function representing the O3-temperature relationship, which indicate that NOx reductions alone can not explain the changes in the temperature dependence of O3. Our analysis would suggest that decreasing NOx concentrations are not the only factor causing the observed changes in the climate penalty factor.

scholarly journals Ozone production in the megacities of Tianjin and Shanghai, China: a comparative study

2012 ◽  
Vol 12 (4) ◽  
pp. 9161-9194 ◽  
Author(s):  
L. Ran ◽  
C. S. Zhao ◽  
W. Y. Xu ◽  
M. Han ◽  
X. Q. Lu ◽  
...  
Keyword(s):  
Comparative Study ◽  
Surface Ozone ◽  
Regional Scale ◽  
Yangtze River Delta ◽  
Scientific Basis ◽  
Ozone Production ◽  
Ozone Pollution ◽  
Light Alkenes ◽  
Highly Nonlinear ◽  
Ozone Precursor

Abstract. Rapid economic growth has given rise to a significant increase in ozone precursor emissions in many regions of China, especially in the densely populated North China Plain (NCP) and Yangtze River Delta (YRD). Improved understanding of ozone formation in response to different precursor emissions is imperative to address the highly nonlinear ozone problem and to provide a solid scientific basis for efficient ozone abatement in these regions. A comparative study on ozone photochemical production in summer has thus been carried out in the megacities of Tianjin (NCP) and Shanghai (YRD). Two intensive field campaigns were carried out respectively at an urban and a suburban site of Tianjin, in addition to routine monitoring of trace gases in Shanghai, providing data sets of surface ozone and its precursors including nitrogen oxides (NOx) and various volatile organic compounds (VOCs). Ozone pollution was found to be more severe in Tianjin than in Shanghai during the summer, either based on the frequency or the duration of high ozone events. Such differences might be attributed to the large amount of highly reactive VOC mixture in the Tianjin region. It is found that industry related species like light alkenes were of particular importance in both urban and suburban Tianjin, while in Shanghai aromatics dominate. In general, the ozone problem in Shanghai is on an urban scale. Stringent control policies on local emissions would help reduce the occurrence of high ozone concentrations. By contrast, ozone pollution in Tianjin is a regional problem. Combined efforts to reduce ozone precursor emissions on a regional scale must be undertaken to bring the ozone problem under control.

scholarly journals The influence of European pollution on ozone in the Near East and northern Africa

2008 ◽  
Vol 8 (1) ◽  
pp. 1913-1950 ◽  
Author(s):  
B. N. Duncan ◽  
J. J. West ◽  
Y. Yoshida ◽  
A. M. Fiore ◽  
J. R. Ziemke
Keyword(s):  
Boundary Layer ◽  
Air Quality ◽  
Near East ◽  
Surface Ozone ◽  
Northern Africa ◽  
Ozone Production ◽  
Ozone Pollution ◽  
East European ◽  
European Health ◽  
Ozone Precursor

Abstract. We present a modeling study of the long-range transport of pollution from Europe, showing that European emissions regularly elevate surface ozone by as much as 20 ppbv in summer in northern Africa and the Near East. European emissions cause 50–150 additional violations per year (i.e., above those that would occur without European pollution) of the European health standard for ozone (8-h average >120 μg/m3 or ~60 ppbv) in northern Africa and the Near East. We estimate that 19 000 additional mortalities occur annually in these regions from exposure to European ozone pollution and 50 000 additional deaths globally; the majority of the additional deaths occurs outside of Europe. Much of the pollution from Europe is exported southward at low altitudes in summer to the Mediterranean Sea, northern Africa and the Near East, regions with favorable photochemical environments for ozone production. Our results suggest that assessments of the human health benefits of reducing ozone precursor emissions in Europe should include effects outside of Europe, and that comprehensive planning to improve air quality in northern Africa and the Near East likely needs to address European emissions. We also show that the tropospheric ozone column data product derived from the OMI and MLS instruments is currently of limited value for air quality applications as the portion of the column above the boundary layer and below the tropopause is large and variable, effectively obscuring the boundary layer signal.

scholarly journals The mechanisms and meteorological drivers of the summertime ozone–temperature relationship

2019 ◽  
Vol 19 (21) ◽  
pp. 13367-13381 ◽  
Author(s):  
William C. Porter ◽  
Colette L. Heald
Keyword(s):  
United States ◽  
Temperature Dependence ◽  
Transport Model ◽  
Surface Ozone ◽  
The United States ◽  
Reaction Rates ◽  
Temperature Relationship ◽  
Nox Emissions ◽  
Temperature Dependent ◽  
Temperature Correlation

Abstract. Surface ozone (O3) pollution levels are strongly correlated with daytime surface temperatures, especially in highly polluted regions. This correlation is nonlinear and occurs through a variety of temperature-dependent mechanisms related to O3 precursor emissions, lifetimes, and reaction rates, making the reproduction of temperature sensitivities – and the projection of associated human health risks – a complex problem. Here we explore the summertime O3–temperature relationship in the United States and Europe using the chemical transport model GEOS-Chem. We remove the temperature dependence of several mechanisms most frequently cited as causes of the O3–temperature “climate penalty”, including PAN decomposition, soil NOx emissions, biogenic volatile organic compound (VOC) emissions, and dry deposition. We quantify the contribution of each mechanism to the overall correlation between O3 and temperature both individually and collectively. Through this analysis we find that the thermal decomposition of PAN can explain, on average, 20 % of the overall O3–temperature correlation in the United States. The effect is weaker in Europe, explaining 9 % of the overall O3–temperature relationship. The temperature dependence of biogenic emissions contributes 3 % and 9 % of the total O3–temperature correlation in the United States and Europe on average, while temperature-dependent deposition (6 % and 1 %) and soil NOx emissions (10 % and 7 %) also contribute. Even considered collectively these mechanisms explain less than 46 % of the modeled O3–temperature correlation in the United States and 36 % in Europe. We use commonality analysis to demonstrate that covariance with other meteorological phenomena such as stagnancy and humidity can explain the bulk of the remainder of the O3–temperature correlation. Thus, we demonstrate that the statistical correlation between O3 and temperature alone may greatly overestimate the direct impacts of temperature on O3, with implications for the interpretation of policy-relevant metrics such as climate penalty.

scholarly journals The mechanisms and meteorological drivers of the ozone–temperature relationship

2019 ◽  
Author(s):  
William C. Porter ◽  
Colette L. Heald
Keyword(s):  
United States ◽  
Temperature Dependence ◽  
Transport Model ◽  
Surface Ozone ◽  
The United States ◽  
Reaction Rates ◽  
Temperature Relationship ◽  
Nox Emissions ◽  
Temperature Dependent ◽  
Temperature Correlation

Abstract. Surface ozone (O3) pollution levels are strongly correlated with daytime surface temperatures, especially in highly polluted regions. This correlation is nonlinear and occurs through a variety of temperature dependent mechanisms related to O3 precursor emissions, lifetimes, and reaction rates, making the reproduction of temperature sensitivities – and the projection of associated human health risks – a complex problem. Here we explore the summertime O3–temperature relationship in the United States and Europe using the chemical transport model GEOS-Chem. We remove the temperature dependence of several mechanisms most frequently cited as causes of the O3–temperature climate penalty, including: PAN decomposition, soil NOx emissions, biogenic VOC emissions, and dry deposition. We quantify the contribution of each mechanism to the overall correlation between O3 and temperature both individually and collectively. Through this analysis we find that the thermal decomposition of PAN can explain, on average, 20 % of the overall O3–temperature correlation in the United States. The effect is weaker in Europe, explaining 9 % of the overall O3–temperature relationship. The temperature dependence of biogenic emissions contributes 3 % and 9 % of the total O3–temperature correlation in the United States and Europe on average, while temperature dependent deposition (6 % and 1 %) and soil NOx emissions (10 % and 7 %) also contribute. Even considered collectively these mechanisms explain less than 46 % of the modeled O3–temperature correlation in the United States and 36 % in Europe. We use commonality analysis to demonstrate that covariance with other meteorological phenomena such as stagnancy and humidity can explain the bulk of the remainder of the O3–temperature correlation. Thus, we demonstrate that the statistical correlation between O3 and temperature alone may greatly overestimate the direct impacts of temperature on O3, with implications for the interpretation of policy-relevant metrics such as climate penalty.

scholarly journals The influence of European pollution on ozone in the Near East and northern Africa

2008 ◽  
Vol 8 (8) ◽  
pp. 2267-2283 ◽  
Author(s):  
B. N. Duncan ◽  
J. J. West ◽  
Y. Yoshida ◽  
A. M. Fiore ◽  
J. R. Ziemke
Keyword(s):  
Near East ◽  
Surface Ozone ◽  
Northern Africa ◽  
Ozone Production ◽  
Ozone Pollution ◽  
Comprehensive Planning ◽  
East European ◽  
Range Transport ◽  
European Health ◽  
Ozone Precursor

Abstract. We present a modeling study of the long-range transport of pollution from Europe, showing that European emissions regularly elevate surface ozone by as much as 20 ppbv in summer in northern Africa and the Near East. European emissions cause 50–150 additional violations per year (i.e. above those that would occur without European pollution) of the European health standard for ozone (8-h average >120 μg/m3 or ~60 ppbv) in northern Africa and the Near East. We estimate that European ozone pollution is responsible for 50 000 premature mortalities globally each year, of which the majority occurs outside of Europe itself, including 37% (19 000) in northern Africa and the Near East. Much of the pollution from Europe is exported southward at low altitudes in summer to the Mediterranean Sea, northern Africa and the Near East, regions with favorable photochemical environments for ozone production. Our results suggest that assessments of the human health benefits of reducing ozone precursor emissions in Europe should include effects outside of Europe, and that comprehensive planning to improve air quality in northern Africa and the Near East likely needs to address European emissions.

scholarly journals Trends and Variability of Ozone Pollution over the Mountain-Basin Areas in Sichuan Province during 2013–2020: Synoptic Impacts and Formation Regimes

Atmosphere ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1557
Author(s):  
Youfan Chen ◽  
Han Han ◽  
Murong Zhang ◽  
Yuanhong Zhao ◽  
Yipeng Huang ◽  
...  
Keyword(s):  
High Pressure ◽  
Surface Ozone ◽  
Emission Control ◽  
Warm Season ◽  
Sichuan Province ◽  
Ozone Production ◽  
Daily Maximum ◽  
Ozone Pollution ◽  
Reanalysis Dataset ◽  
Ozone Levels

Sichuan Province, the most industrialized and populated region in southwestern China, has been experiencing severe ozone pollution in the boreal warm season (April–September). With a surface ozone monitoring network and reanalysis dataset, we find that nearly all cities in Sichuan Province showed positive increasing trends in the warm-season ozone levels. The warm-season daily maximum 8-h average (MDA8) ozone levels increased by 2.0 ppb (4.8%) year−1 as a whole, with slightly larger trends in some sites such as a site in Zigong (5.2 ppb year−1). Seasonally, the monthly ozone level in Sichuan peaks from May to August (varies with year). The predominant warm-season synoptic patterns were objectively identified based on concurrent hourly meteorological fields from ERA5. High-pressure systems promote ozone production and result in high ozone concentrations, due to strong solar radiation as well as hot and dry atmospheric conditions. The increased occurrence of high-pressure patterns probably drives the ozone increase in Sichuan. When ozone pollution is relatively weak (with MDA8 ozone around 170 μg m−3), the air quality standard could be achieved in the short term by a 25% reduction of NOx and VOCs emissions. Strengthened emission control is needed when ozone pollution is more severe. Our study provides implications for effective emission control of ozone pollution in Sichuan.

scholarly journals Ozone production in summer in the megacities of Tianjin and Shanghai, China: a comparative study

2012 ◽  
Vol 12 (16) ◽  
pp. 7531-7542 ◽  
Author(s):  
L. Ran ◽  
C. S. Zhao ◽  
W. Y. Xu ◽  
M. Han ◽  
X. Q. Lu ◽  
...  
Keyword(s):  
Comparative Study ◽  
Surface Ozone ◽  
Regional Scale ◽  
Yangtze River Delta ◽  
Scientific Basis ◽  
Ozone Production ◽  
Ozone Pollution ◽  
Light Alkenes ◽  
Highly Nonlinear ◽  
Ozone Precursor

Abstract. Rapid economic growth has given rise to a significant increase in ozone precursor emissions in many regions of China, especially in the densely populated North China Plain (NCP) and Yangtze River Delta (YRD). Improved understanding of ozone formation in response to different precursor emissions is imperative to address the highly nonlinear ozone problem and to provide a solid scientific basis for efficient ozone abatement in these regions. A comparative study on ozone photochemical production in summer has thus been carried out in the megacities of Tianjin (NCP) and Shanghai (YRD). Two intensive field campaigns were carried out respectively at an urban and a suburban site of Tianjin, in addition to routine monitoring of trace gases in Shanghai, providing data sets of surface ozone and its precursors including nitrogen oxides (NOx) and various non-methane hydrocarbons (NMHCs). Ozone pollution in summer was found to be more severe in the Tianjin region than in the Shanghai region, based on either the frequency or the duration of high ozone events. Such differences might be attributed to the large amount of highly reactive NMHCs in Tianjin. Industry related species like light alkenes were of particular importance in both urban and suburban Tianjin, while in Shanghai aromatics dominated. In general, the ozone problem in Shanghai is on an urban scale. Stringent control policies on local emissions would help reduce the occurrence of high ozone concentrations. By contrast, ozone pollution in Tianjin is probably a regional problem. Combined efforts to reduce ozone precursor emissions on a regional scale must be undertaken to bring the ozone problem under control.

Temperature Dependence of the Critical Electron Dose for Fatty Acid Monolayers

1982 ◽  
Vol 40 ◽  
pp. 78-79
Author(s):  
Kenneth H. Downing ◽  
Robert M. Glaeser
Keyword(s):  
Electron Beam ◽  
Fatty Acid ◽  
Inelastic Scattering ◽  
Temperature Dependence ◽  
Structural Damage ◽  
Direct Result ◽  
Second Step ◽  
Strong Temperature Dependence ◽  
Electron Dose ◽  
Covalent Bonds

The structural damage of molecules irradiated by electrons is generally considered to occur in two steps. The direct result of inelastic scattering events is the disruption of covalent bonds. Following changes in bond structure, movement of the constituent atoms produces permanent distortions of the molecules. Since at least the second step should show a strong temperature dependence, it was to be expected that cooling a specimen should extend its lifetime in the electron beam. This result has been found in a large number of experiments, but the degree to which cooling the specimen enhances its resistance to radiation damage has been found to vary widely with specimen types.

scholarly journals Modelling the impact of megacities on local, regional and global tropospheric ozone and the deposition of nitrogen species

2013 ◽  
Vol 13 (24) ◽  
pp. 12215-12231 ◽  
Author(s):  
Z. S. Stock ◽  
M. R. Russo ◽  
T. M. Butler ◽  
A. T. Archibald ◽  
M. G. Lawrence ◽  
...  
Keyword(s):  
Air Quality ◽  
Urban Areas ◽  
Climate Model ◽  
Surface Ozone ◽  
Global Scale ◽  
Chemical Environment ◽  
Ozone Production ◽  
The Uk ◽  
The Impact ◽  
Local Emissions

Abstract. We examine the effects of ozone precursor emissions from megacities on present-day air quality using the global chemistry–climate model UM-UKCA (UK Met Office Unified Model coupled to the UK Chemistry and Aerosols model). The sensitivity of megacity and regional ozone to local emissions, both from within the megacity and from surrounding regions, is important for determining air quality across many scales, which in turn is key for reducing human exposure to high levels of pollutants. We use two methods, perturbation and tagging, to quantify the impact of megacity emissions on global ozone. We also completely redistribute the anthropogenic emissions from megacities, to compare changes in local air quality going from centralised, densely populated megacities to decentralised, lower density urban areas. Focus is placed not only on how changes to megacity emissions affect regional and global NOx and O3, but also on changes to NOy deposition and to local chemical environments which are perturbed by the emission changes. The perturbation and tagging methods show broadly similar megacity impacts on total ozone, with the perturbation method underestimating the contribution partially because it perturbs the background chemical environment. The total redistribution of megacity emissions locally shifts the chemical environment towards more NOx-limited conditions in the megacities, which is more conducive to ozone production, and monthly mean surface ozone is found to increase up to 30% in megacities, depending on latitude and season. However, the displacement of emissions has little effect on the global annual ozone burden (0.12% change). Globally, megacity emissions are shown to contribute ~3% of total NOy deposition. The changes in O3, NOx and NOy deposition described here are useful for quantifying megacity impacts and for understanding the sensitivity of megacity regions to local emissions. The small global effects of the 100% redistribution carried out in this study suggest that the distribution of emissions on the local scale is unlikely to have large implications for chemistry–climate processes on the global scale.

Investigating the occurrence, likelihood and regional variability of extreme ozone pollution episodes across the UK

2021 ◽  
Author(s):  
Lily Gouldsbrough ◽  
Ryan Hossaini ◽  
Emma Eastoe ◽  
Paul J. Young
Keyword(s):  
Surface Ozone ◽  
Extreme Value Analysis ◽  
Daily Maximum ◽  
Monitoring Site ◽  
Ozone Pollution ◽  
Threshold Method ◽  
Regional Variability ◽  
Value Analysis ◽  
The Uk ◽  
Pollution Episodes

&lt;p&gt;Warm summer temperatures provide ideal conditions for the occurrence of extreme ground level ozone pollution episodes. Given the well-established negative impacts of ozone on human and plant health, understanding and attributing these extreme events is of importance to the scientific and wider community, particularly as heatwaves may become more frequent due to climate change. Extreme Value Analysis provides a powerful and flexible framework in which to statistically model unusually large observed values of ozone extracted from historical data. Here, a temperature dependent Peaks-Over-Threshold method based upon the Generalised Pareto Distribution is used to carry out a regional comparison of extreme ozone pollution episodes within the UK. Our analysis uses surface ozone observations from the UK&amp;#8217;s extensive Automatic Urban and Rural Network. The statistical model was used to quantify the frequency and magnitude of extreme ozone events, including a probabilistic assessment of exceeding UK public health thresholds, conditional on temperature. Return levels are provided for each monitoring site demonstrating the expected future projections of extreme ozone pollution events across the UK. We find that across UK rural background sites, return periods for a daily maximum 8-hr ozone level of 100 ug/m3 (a 'moderate' level of air pollution in the UK's Air Quality Index) range from 32-147 days, based on analysis of the data in the decade 2010-2019. Similarly, for urban background sites the range is 36-869 days. An analysis of the spatio temporal variability in UK ozone extremes, along with their temperature dependence, will be presented.&lt;/p&gt;

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