Ozone pollution in China: A review of concentrations, meteorological influences, chemical precursors, and effects
TL;DR: This review summarizes the main findings from published papers on the characteristics and sources and processes of ozone and ozone precursors in the boundary layer of urban and rural areas of China, including concentration levels, seasonal variation, meteorology conducive to photochemistry and pollution transport, key production and loss processes, ozone dependence on nitrogen oxides and volatile organic compounds, and the effects of ozone on crops and human health.
About: This article is published in Science of The Total Environment.The article was published on 2017-01-01. It has received 952 citations till now. The article focuses on the topics: Ozone & Pollution.
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TL;DR: In this article, the effect of meteorological variability on ozone trends was investigated using a multiple linear regression model and the residual of this regression showed increasing ozone trends of 1-3 ppbv a−1 in megacity clusters of eastern China that they attributed to changes in anthropogenic emissions.
Abstract: Observations of surface ozone available from ∼1,000 sites across China for the past 5 years (2013–2017) show severe summertime pollution and regionally variable trends. We resolve the effect of meteorological variability on the ozone trends by using a multiple linear regression model. The residual of this regression shows increasing ozone trends of 1–3 ppbv a−1 in megacity clusters of eastern China that we attribute to changes in anthropogenic emissions. By contrast, ozone decreased in some areas of southern China. Anthropogenic NOx emissions in China are estimated to have decreased by 21% during 2013–2017, whereas volatile organic compounds (VOCs) emissions changed little. Decreasing NOx would increase ozone under the VOC-limited conditions thought to prevail in urban China while decreasing ozone under rural NOx-limited conditions. However, simulations with the Goddard Earth Observing System Chemical Transport Model (GEOS-Chem) indicate that a more important factor for ozone trends in the North China Plain is the ∼40% decrease of fine particulate matter (PM2.5) over the 2013–2017 period, slowing down the aerosol sink of hydroperoxy (HO2) radicals and thus stimulating ozone production.
864 citations
TL;DR: It is shown that the haze during the COVID lockdown was driven by enhancements of secondary pollution, and that haze mitigation depends upon a coordinated and balanced strategy for controlling multiple pollutants.
Abstract: To control the spread of the 2019 novel coronavirus (COVID-19), China imposed nationwide restrictions on the movement of its population (lockdown) after the Chinese New Year of 2020, leading to large reductions in economic activities and associated emissions Despite such large decreases in primary pollution, there were nonetheless several periods of heavy haze pollution in eastern China, raising questions about the well-established relationship between human activities and air quality Here, using comprehensive measurements and modeling, we show that the haze during the COVID lockdown was driven by enhancements of secondary pollution In particular, large decreases in NOx emissions from transportation increased ozone and nighttime NO3 radical formation, and these increases in atmospheric oxidizing capacity in turn facilitated the formation of secondary particulate matter Our results, afforded by the tragic natural experiment of the COVID-19 pandemic, indicate that haze mitigation depends upon a coordinated and balanced strategy for controlling multiple pollutants
529 citations
TL;DR: Wang et al. as mentioned in this paper used the latest 5-year (2013-2017) surface ozone measurements from the Chinese monitoring network, combined with the recent Tropospheric Ozone Assessment Report (TOAR) database for other industrialized regions such as Japan, South Korea, Europe, and the United States (JKEU).
Abstract: The nationwide extent of surface ozone pollution in China and its comparison to the global ozone distribution have not been recognized because of the scarcity of Chinese monitoring sites before 2012. Here we address this issue by using the latest 5 year (2013–2017) surface ozone measurements from the Chinese monitoring network, combined with the recent Tropospheric Ozone Assessment Report (TOAR) database for other industrialized regions such as Japan, South Korea, Europe, and the United States (JKEU). We use various human health and vegetation exposure metrics. We find that although the median ozone values are comparable between Chinese and JKEU cities, the magnitude and frequency of high-ozone events are much larger in China. The national warm-season (April–September) fourth highest daily maximum 8 h average (4MDA8) ozone level (86.0 ppb) and the number of days with MDA8 values of >70 ppb (NDGT70, 29.7 days) in China are 6.3–30% (range of regional mean differences) and 93–575% higher, respectively, than ...
517 citations
TL;DR: Though the air quality has been improving recent years, PM2.5 pollution in wintertime is worsening, especially in the Northern China, and more scientific air quality index standards are needed.
482 citations
TL;DR: In this paper, the authors show observational evidence for this effect with 2013-2018 summer data of hourly ozone and PM2.5 concentrations from 106 sites in the North China Plain.
Abstract: Fine particulate matter (PM2.5) decreased by 30–40% across China during 2013–2017 in response to the governmental Clean Air Action. However, surface ozone pollution worsened over the same period. Model simulations have suggested that the increase in ozone could be driven by the decrease in PM2.5, because PM2.5 scavenges hydroperoxy (HO2) and NOx radicals that would otherwise produce ozone. Here we show observational evidence for this effect with 2013–2018 summer data of hourly ozone and PM2.5 concentrations from 106 sites in the North China Plain. The observations show suppression of ozone pollution at high PM2.5 concentrations, consistent with a model simulation in which PM2.5 scavenging of HO2 and NOx depresses ozone concentrations by 25 ppb relative to PM2.5-free conditions. PM2.5 chemistry makes ozone pollution less sensitive to NOx emission controls, emphasizing the need for controlling emissions of volatile organic compounds (VOCs), which so far have not decreased in China. The new 2018–2020 Clean Air Action plan calls for a 10% decrease in VOC emissions that should begin to reverse the long-term ozone increase even as PM2.5 continues to decrease. Aggressive reduction of NOx and aromatic VOC emissions should be particularly effective for decreasing both PM2.5 and ozone. Observations confirm that cleaning up fine particulate matter in the North China Plain has exacerbated ozone pollution, suggesting that both NOx and VOC emissions need to be reduced to improve air quality.
411 citations
References
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31 Dec 2006
1,591 citations
TL;DR: In this article, the authors developed a new emission inventory for Asia (Regional Emission inventory in ASia (REAS) Version 1.1) for the period 1980-2020.
Abstract: . We developed a new emission inventory for Asia (Regional Emission inventory in ASia (REAS) Version 1.1) for the period 1980–2020. REAS is the first inventory to integrate historical, present, and future emissions in Asia on the basis of a consistent methodology. We present here emissions in 2000, historical emissions for 1980–2003, and projected emissions for 2010 and 2020 of SO2, NOx, CO, NMVOC, black carbon (BC), and organic carbon (OC) from fuel combustion and industrial sources. Total energy consumption in Asia more than doubled between 1980 and 2003, causing a rapid growth in Asian emissions, by 28% for BC, 30% for OC, 64% for CO, 108% for NMVOC, 119% for SO2, and 176% for NOx. In particular, Chinese NOx emissions showed a marked increase of 280% over 1980 levels, and growth in emissions since 2000 has been extremely high. These increases in China were mainly caused by increases in coal combustion in the power plants and industrial sectors. NMVOC emissions also rapidly increased because of growth in the use of automobiles, solvents, and paints. By contrast, BC, OC, and CO emissions in China showed decreasing trends from 1996 to 2000 because of a reduction in the use of biofuels and coal in the domestic and industry sectors. However, since 2000, Chinese emissions of these species have begun to increase. Thus, the emissions of air pollutants in Asian countries (especially China) showed large temporal variations from 1980–2003. Future emissions in 2010 and 2020 in Asian countries were projected by emission scenarios and from emissions in 2000. For China, we developed three emission scenarios: PSC (policy success case), REF (reference case), and PFC (policy failure case). In the 2020 REF scenario, Asian total emissions of SO2, NOx, and NMVOC were projected to increase substantially by 22%, 44%, and 99%, respectively, over 2000 levels. The 2020 REF scenario showed a modest increase in CO (12%), a lesser increase in BC (1%), and a slight decrease in OC (−5%) compared with 2000 levels. However, it should be noted that Asian total emissions are strongly influenced by the emission scenarios for China.
1,388 citations
"Ozone pollution in China: A review ..." refers background in this paper
...Emission of VOCs have also increased in mainland China since the 1980s (Lu et al., 2013; Ohara et al., 2007), with no turning point up to 2014 according to satellite data on formaldehyde vertical column (De Smedt et al....
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...Emission of VOCs have also increased in mainland China since the 1980s (Lu et al., 2013; Ohara et al., 2007), with no turning point up to 2014 according to satellite data on formaldehyde vertical column (De Smedt et al., 2015)....
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...…emission and satellite data (Duncan et al., 2016; http://data.stats.gov.cn/; Krotkov et al., 2016; Kurokawa et al., 2013; Mijling et al., 2013; Ohara et al., 2007; Richter et al., 2005; bserved ozone recursors Maximum O3 (ppbv) Reference Ox,CO, VOCsa ~200 Wang et al. (1998), Wang et al.…...
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TL;DR: There are substantial reductions in nitrogen dioxide concentrations over some areas of Europe and the USA, but a highly significant increase of about 50 per cent—with an accelerating trend in annual growth rate—over the industrial areas of China, more than recent bottom-up inventories suggest.
Abstract: The rapid expansion of the Chinese economy is making its mark on the environment. Atmospheric pollution due to the release of nitrogen oxides from fossil fuel and biomass burning is expected to decrease in most industrialized countries but in some parts of the world rapid economic development could have the opposite effect. Satellite observations over the period 1996–2004 now provide confirmation of these predictions. Across parts of Europe and North America there have been dramatic reductions in nitrogen oxide concentrations in the lower atmosphere (the troposphere). But there was a significant increase of about 50% — with an accelerating trend in annual growth rate — over the industrial areas of China; this is much larger than predictions made based on emission inventories. Emissions from fossil fuel combustion and biomass burning reduce local air quality and affect global tropospheric chemistry. Nitrogen oxides are emitted by all combustion processes and play a key part in the photochemically induced catalytic production of ozone, which results in summer smog and has increased levels of tropospheric ozone globally1. Release of nitrogen oxide also results in nitric acid deposition, and—at least locally—increases radiative forcing effects due to the absorption of downward propagating visible light2. Nitrogen oxide concentrations in many industrialized countries are expected to decrease3, but rapid economic development has the potential to increase significantly the emissions of nitrogen oxides4,5,6,7 in parts of Asia. Here we present the tropospheric column amounts of nitrogen dioxide retrieved from two satellite instruments GOME8,9 and SCIAMACHY10 over the years 1996–2004. We find substantial reductions in nitrogen dioxide concentrations over some areas of Europe and the USA, but a highly significant increase of about 50 per cent—with an accelerating trend in annual growth rate—over the industrial areas of China, more than recent bottom-up inventories suggest6.
1,234 citations
"Ozone pollution in China: A review ..." refers background in this paper
...…data (Duncan et al., 2016; http://data.stats.gov.cn/; Krotkov et al., 2016; Kurokawa et al., 2013; Mijling et al., 2013; Ohara et al., 2007; Richter et al., 2005; bserved ozone recursors Maximum O3 (ppbv) Reference Ox,CO, VOCsa ~200 Wang et al. (1998), Wang et al. (2003), Wang et al.…...
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TL;DR: A statistically significant association between short-term changes in ozone and mortality on average for 95 large US urban communities, which include about 40% of the total US population, indicates that this widespread pollutant adversely affects public health.
Abstract: Design and Setting Using analytical methods and databases developed for the National Morbidity, Mortality, and Air Pollution Study, we estimated a national average relative rate of mortality associated with short-term exposure to ambient ozone for 95 large US urban communities from 1987-2000. We used distributed-lag models for estimating community-specific relative rates of mortality adjusted for time-varying confounders (particulate matter, weather, seasonality, and long-term trends) and hierarchical models for combining relative rates across communities to estimate a national average relative rate, taking into account spatial heterogeneity. Main Outcome Measure Daily counts of total non–injury-related mortality and cardiovascular and respiratory mortality in 95 large US communities during a 14-year period. Results A 10-ppb increase in the previous week’s ozone was associated with a 0.52% increase in daily mortality (95% posterior interval [PI], 0.27%-0.77%) and a 0.64% increase in cardiovascular and respiratory mortality (95% PI, 0.31%-0.98%). Effect estimates for aggregate ozone during the previous week were larger than for models considering only a single day’s exposure. Results were robust to adjustment for particulate matter, weather, seasonality, and long-term trends. Conclusions These results indicate a statistically significant association between shortterm changes in ozone and mortality on average for 95 large US urban communities, which include about 40% of the total US population. The findings indicate that this widespread pollutant adversely affects public health. JAMA. 2004;292:2372-2378 www.jama.com
1,151 citations
"Ozone pollution in China: A review ..." refers background in this paper
...Although numerous studies have been done on the epidemiology of ozone (e.g. Bell et al., 2007; Bell et al., 2004), they are less common in China (e.g. Yang et al., 2012)....
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University of Leicester1, University of Cambridge2, Cooperative Institute for Research in Environmental Sciences3, Newbury College4, Earth System Research Laboratory5, University of Paris6, University of Edinburgh7, Paul Sabatier University8, Potsdam Institute for Climate Impact Research9, Lancaster University10, King's College London11
TL;DR: In this paper, a review examines current understanding of the processes regulating tropospheric ozone at global to local scales from both measurements and models and takes the view that knowledge across the scales is important for dealing with air quality and climate change in a synergistic manner.
Abstract: Ozone holds a certain fascination in atmospheric science. It is ubiquitous in the atmosphere, central to tropospheric oxidation chemistry, yet harmful to human and ecosystem health as well as being an important greenhouse gas. It is not emitted into the atmosphere but is a by-product of the very oxidation chemistry it largely initiates. Much effort is focussed on the reduction of surface levels of ozone owing to its health impacts but recent efforts to achieve reductions in exposure at a country scale have proved difficult to achieve due to increases in background ozone at the zonal hemispheric scale. There is also a growing realisation that the role of ozone as a short-lived climate pollutant could be important in integrated air quality climate-change mitigation. This review examines current understanding of the processes regulating tropospheric ozone at global to local scales from both measurements and models. It takes the view that knowledge across the scales is important for dealing with air quality and climate change in a synergistic manner.
877 citations
"Ozone pollution in China: A review ..." refers background in this paper
...Because of its importance to air quality and climate change, O3 has received continuous attention in the past three decades from both the scientific and regulatory communities (e.g., Monks et al., 2015; NARSTO, 2000; NRC, 1991)....
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