Seasonal and spatial variability of surface ozone over China: contributions from background and domestic pollution

Abstract. Both observations and a 3-D chemical transport model suggest that surface ozone over populated eastern China features a significant drop in mid-summer and that the peak month differs by latitude and region. Source-receptor analysis is used to quantify the contributions of background ozone and Chinese anthropogenic emissions on this variability. Annual mean background ozone over China shows a spatial gradient from 55 ppbv in the northwest to 20 ppbv in the southeast, corresponding with changes in topography and ozone lifetime. Anthropogenic background (annual mean of 12.6 ppbv) shows distinct troughs in the summer and peaks in the spring. On the monthly-mean basis, Chinese pollution ozone (CPO) has a peak of 20–25 ppbv in June north of the Yangtze River and in October south of it, which explains the peaks of surface ozone in these months. The mid-summer drop in ozone over eastern China is driven by the decrease of background ozone (−15 ppbv). Tagged simulations suggest that this decrease is driven by reduced transport from Europe and North America, whereas ozone from Southeast Asia and Pacific Ocean exhibits a maximum in the summer over eastern China. This contrast in seasonality provides clear evidence that the seasonal switch in monsoonal wind patterns plays a significant role in determining the seasonality of background ozone over China.

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Seasonal and spatial variability of surface ozone over China: contributions from background and domestic pollution

Atmospheric Chemistry and Physics ◽

10.5194/acp-11-3511-2011 ◽

2011 ◽

Vol 11 (7) ◽

pp. 3511-3525 ◽

Cited By ~ 105

Author(s):

Y. Wang ◽

Y. Zhang ◽

J. Hao ◽

M. Luo

Keyword(s):

Yangtze River ◽

Transport Model ◽

Surface Ozone ◽

Eastern China ◽

Long Range Transport ◽

Anthropogenic Emissions ◽

Spatial Gradient ◽

Chemical Transport Model ◽

Background Ozone ◽

Range Transport

Abstract. Both observations and a 3-D chemical transport model suggest that surface ozone over populated eastern China features a summertime trough and that the month when surface ozone peaks differs by latitude and region. Source-receptor analysis is used to quantify the contributions of background ozone and Chinese anthropogenic emissions on this variability. Annual mean background ozone over China shows a spatial gradient from 55 ppbv in the northwest to 20 ppbv in the southeast, corresponding with changes in topography and ozone lifetime. Pollution background ozone (annual mean of 12.6 ppbv) shows a minimum in the summer and maximum in the spring. On the monthly-mean basis, Chinese pollution ozone (CPO) has a peak of 20–25 ppbv in June north of the Yangtze River and in October south of it, which explains the peaks of surface ozone in these months. The summertime trough in surface ozone over eastern China can be explained by the decrease of background ozone from spring to summer (by −15 ppbv regionally averaged over eastern China). Tagged simulations suggest that long-range transport of ozone from northern mid-latitude continents (including Europe and North America) reaches a minimum in the summer, whereas ozone from Southeast Asia exhibits a maximum in the summer over eastern China. This contrast in seasonality provides clear evidence that the seasonal switch in monsoonal wind patterns plays a significant role in determining the seasonality of background ozone over China.

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Effects of Dry Deposition on Surface Ozone over South Asia Inferred from a Regional Chemical Transport Model

ACS Earth and Space Chemistry ◽

10.1021/acsearthspacechem.0c00004 ◽

2020 ◽

Vol 4 (2) ◽

pp. 321-327 ◽

Cited By ~ 1

Author(s):

Amit Sharma ◽

Narendra Ojha ◽

Tabish U. Ansari ◽

Som K. Sharma ◽

Andrea Pozzer ◽

...

Keyword(s):

South Asia ◽

Dry Deposition ◽

Transport Model ◽

Surface Ozone ◽

Chemical Transport ◽

Chemical Transport Model

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Coupling between surface ozone and leaf area index in a chemical transport model: strength of feedback and implications for ozone air quality and vegetation health

Atmospheric Chemistry and Physics ◽

10.5194/acp-18-14133-2018 ◽

2018 ◽

Vol 18 (19) ◽

pp. 14133-14148 ◽

Cited By ~ 10

Author(s):

Shan S. Zhou ◽

Amos P. K. Tai ◽

Shihan Sun ◽

Mehliyar Sadiq ◽

Colette L. Heald ◽

...

Keyword(s):

Air Quality ◽

Leaf Area Index ◽

Leaf Area ◽

Dry Deposition ◽

Transport Model ◽

Surface Ozone ◽

Chemical Transport ◽

Chemical Transport Model ◽

Area Index ◽

Ozone Levels

Abstract. Tropospheric ozone is an air pollutant that substantially harms vegetation and is also strongly dependent on various vegetation-mediated processes. The interdependence between ozone and vegetation may constitute feedback mechanisms that can alter ozone concentration itself but have not been considered in most studies to date. In this study we examine the importance of dynamic coupling between surface ozone and leaf area index (LAI) in shaping ozone air quality and vegetation. We first implement an empirical scheme for ozone damage on vegetation in the Community Land Model (CLM) and simulate the steady-state responses of LAI to long-term exposure to a range of prescribed ozone levels (from 0 to 100 ppb). We find that most plant functional types suffer a substantial decline in LAI as ozone level increases. Based on the CLM-simulated results, we develop and implement in the GEOS-Chem chemical transport model a parameterization that computes fractional changes in monthly LAI as a function of local mean ozone levels. By forcing LAI to respond to ozone concentrations on a monthly timescale, the model simulates ozone–LAI coupling dynamically via biogeochemical processes including biogenic volatile organic compound (VOC) emissions and dry deposition, without the complication from meteorological changes. We find that ozone-induced damage on LAI can lead to changes in ozone concentrations by −1.8 to +3 ppb in boreal summer, with a corresponding ozone feedback factor of −0.1 to +0.6 that represents an overall self-amplifying effect from ozone–LAI coupling. Substantially higher simulated ozone due to strong positive feedbacks is found in most tropical forests, mainly due to the ozone-induced reductions in LAI and dry deposition velocity, whereas reduced isoprene emission plays a lesser role in these low-NOx environments. In high-NOx regions such as the eastern US, Europe, and China, however, the feedback effect is much weaker and even negative in some regions, reflecting the compensating effects of reduced dry deposition and reduced isoprene emission (which reduces ozone in high-NOx environments). In remote, low-LAI regions, including most of the Southern Hemisphere, the ozone feedback is generally slightly negative due to the reduced transport of NOx–VOC reaction products that serve as NOx reservoirs. This study represents the first step to accounting for dynamic ozone–vegetation coupling in a chemical transport model with ramifications for a more realistic joint assessment of ozone air quality and ecosystem health.

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Implementation of Yale Interactive terrestrial Biosphere model v1.0 into GEOS-Chem v12.0.0: a tool for biosphere–chemistry interactions

Geoscientific Model Development ◽

10.5194/gmd-13-1137-2020 ◽

2020 ◽

Vol 13 (3) ◽

pp. 1137-1153 ◽

Cited By ~ 2

Author(s):

Yadong Lei ◽

Xu Yue ◽

Hong Liao ◽

Cheng Gong ◽

Lin Zhang

Keyword(s):

Stomatal Conductance ◽

Atmospheric Chemistry ◽

Dry Deposition ◽

Transport Model ◽

Surface Ozone ◽

Eastern China ◽

Deposition Velocity ◽

Chemical Transport Model ◽

Terrestrial Biosphere ◽

Area Index

Abstract. The terrestrial biosphere and atmospheric chemistry interact through multiple feedbacks, but the models of vegetation and chemistry are developed separately. In this study, the Yale Interactive terrestrial Biosphere (YIBs) model, a dynamic vegetation model with biogeochemical processes, is implemented into the Chemical Transport Model GEOS-Chem (GC) version 12.0.0. Within this GC-YIBs framework, leaf area index (LAI) and canopy stomatal conductance dynamically predicted by YIBs are used for dry deposition calculation in GEOS-Chem. In turn, the simulated surface ozone (O3) by GEOS-Chem affect plant photosynthesis and biophysics in YIBs. The updated stomatal conductance and LAI improve the simulated O3 dry deposition velocity and its temporal variability for major tree species. For daytime dry deposition velocities, the model-to-observation correlation increases from 0.69 to 0.76, while the normalized mean error (NME) decreases from 30.5 % to 26.9 % using the GC-YIBs model. For the diurnal cycle, the NMEs decrease by 9.1 % for Amazon forests, 6.8 % for coniferous forests, and 7.9 % for deciduous forests using the GC-YIBs model. Furthermore, we quantify the damaging effects of O3 on vegetation and find a global reduction of annual gross primary productivity by 1.5 %–3.6 %, with regional extremes of 10.9 %–14.1 % in the eastern USA and eastern China. The online GC-YIBs model provides a useful tool for discerning the complex feedbacks between atmospheric chemistry and the terrestrial biosphere under global change.

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Exploring the trends and potential drivers of surface ozone in eastern China in 2015-2018

10.5194/egusphere-egu2020-8194 ◽

2020 ◽

Author(s):

Ning Yang ◽

Yanru Bai ◽

Yong Zhu ◽

Nan Ma ◽

Qiaoqiao Wang

Keyword(s):

Air Quality ◽

Transport Model ◽

Surface Ozone ◽

Eastern China ◽

Yangtze River Delta ◽

River Delta ◽

Pearl River Delta Region ◽

Chemical Transport Model ◽

Delta Region ◽

Almost All

In the last six years, China has experienced significant improvement in air quality due to great emission reduction efforts. However, ozone concentrations are still slowly increasing in three major regions of eastern China, respectively Jing-Jin-Ji(JJJ), Yangtze River Delta region(YRD) and Pearl River Delta region(PRD). It is shown from the 2015-2018 national urban air quality real-time release platform that the surface ozone in JJJ, YRD and PRD has increased each year and reached the highest in 2018. The monthly ozone concentration peaked in June in almost all cities of JJJ, while it had multiple peaks in other two regions (summer and autumn in YRD - and February, May and September in PRD). Simulation with a chemical transport model(GEOS-Chem) indicates that the formation of ozone is affected by the optical properties of PM2.5 and also the heterogeneous uptake of N2O5 on sea salt aerosol.

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Source attribution of Arctic black carbon constrained by aircraft and surface measurements

Atmospheric Chemistry and Physics ◽

10.5194/acp-17-11971-2017 ◽

2017 ◽

Vol 17 (19) ◽

pp. 11971-11989 ◽

Cited By ~ 30

Author(s):

Jun-Wei Xu ◽

Randall V. Martin ◽

Andrew Morrow ◽

Sangeeta Sharma ◽

Lin Huang ◽

...

Keyword(s):

North America ◽

Biomass Burning ◽

Western Siberia ◽

Transport Model ◽

Chemical Transport ◽

The Arctic ◽

Anthropogenic Emissions ◽

Chemical Transport Model ◽

Northern Asia ◽

Airborne Measurements

Abstract. Black carbon (BC) contributes to Arctic warming, yet sources of Arctic BC and their geographic contributions remain uncertain. We interpret a series of recent airborne (NETCARE 2015; PAMARCMiP 2009 and 2011 campaigns) and ground-based measurements (at Alert, Barrow and Ny-Ålesund) from multiple methods (thermal, laser incandescence and light absorption) with the GEOS-Chem global chemical transport model and its adjoint to attribute the sources of Arctic BC. This is the first comparison with a chemical transport model of refractory BC (rBC) measurements at Alert. The springtime airborne measurements performed by the NETCARE campaign in 2015 and the PAMARCMiP campaigns in 2009 and 2011 offer BC vertical profiles extending to above 6 km across the Arctic and include profiles above Arctic ground monitoring stations. Our simulations with the addition of seasonally varying domestic heating and of gas flaring emissions are consistent with ground-based measurements of BC concentrations at Alert and Barrow in winter and spring (rRMSE  < 13 %) and with airborne measurements of the BC vertical profile across the Arctic (rRMSE  = 17 %) except for an underestimation in the middle troposphere (500–700 hPa).Sensitivity simulations suggest that anthropogenic emissions in eastern and southern Asia have the largest effect on the Arctic BC column burden both in spring (56 %) and annually (37 %), with the largest contribution in the middle troposphere (400–700 hPa). Anthropogenic emissions from northern Asia contribute considerable BC (27 % in spring and 43 % annually) to the lower troposphere (below 900 hPa). Biomass burning contributes 20 % to the Arctic BC column annually.At the Arctic surface, anthropogenic emissions from northern Asia (40–45 %) and eastern and southern Asia (20–40 %) are the largest BC contributors in winter and spring, followed by Europe (16–36 %). Biomass burning from North America is the most important contributor to all stations in summer, especially at Barrow.Our adjoint simulations indicate pronounced spatial heterogeneity in the contribution of emissions to the Arctic BC column concentrations, with noteworthy contributions from emissions in eastern China (15 %) and western Siberia (6.5 %). Although uncertain, gas flaring emissions from oilfields in western Siberia could have a striking impact (13 %) on Arctic BC loadings in January, comparable to the total influence of continental Europe and North America (6.5 % each in January). Emissions from as far as the Indo-Gangetic Plain could have a substantial influence (6.3 % annually) on Arctic BC as well.

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Impact of regional climate change and future emission scenarios on surface O3 and PM2.5 over India

Atmospheric Chemistry and Physics ◽

10.5194/acp-18-103-2018 ◽

2018 ◽

Vol 18 (1) ◽

pp. 103-127 ◽

Cited By ~ 17

Author(s):

Matthieu Pommier ◽

Hilde Fagerli ◽

Michael Gauss ◽

David Simpson ◽

Sumit Sharma ◽

...

Keyword(s):

Climate Change ◽

Transport Model ◽

Surface Ozone ◽

Deposition Velocity ◽

Public Health Issue ◽

Anthropogenic Emissions ◽

Reference Scenario ◽

Chemical Transport Model ◽

Data Set ◽

Gangetic Plain

Abstract. Eleven of the world's 20 most polluted cities are located in India and poor air quality is already a major public health issue. However, anthropogenic emissions are predicted to increase substantially in the short-term (2030) and medium-term (2050) futures in India, especially if no further policy efforts are made. In this study, the EMEP/MSC-W chemical transport model has been used to predict changes in surface ozone (O3) and fine particulate matter (PM2.5) for India in a world of changing emissions and climate. The reference scenario (for present-day) is evaluated against surface-based measurements, mainly at urban stations. The evaluation has also been extended to other data sets which are publicly available on the web but without quality assurance. The evaluation shows high temporal correlation for O3 (r =  0.9) and high spatial correlation for PM2.5 (r =  0.5 and r =  0.8 depending on the data set) between the model results and observations. While the overall bias in PM2.5 is small (lower than 6 %), the model overestimates O3 by 35 %. The underestimation in NOx titration is probably the main reason for the O3 overestimation in the model. However, the level of agreement can be considered satisfactory in this case of a regional model being evaluated against mainly urban measurements, and given the inevitable uncertainties in much of the input data.For the 2050s, the model predicts that climate change will have distinct effects in India in terms of O3 pollution, with a region in the north characterized by a statistically significant increase by up to 4 % (2 ppb) and one in the south by a decrease up to −3 % (−1.4 ppb). This variation in O3 is assumed to be partly related to changes in O3 deposition velocity caused by changes in soil moisture and, over a few areas, partly also by changes in biogenic non-methane volatile organic compounds.Our calculations suggest that PM2.5 will increase by up to 6.5 % over the Indo-Gangetic Plain by the 2050s. The increase over India is driven by increases in dust, particulate organic matter (OM) and secondary inorganic aerosols (SIAs), which are mainly affected by the change in precipitation, biogenic emissions and wind speed.The large increase in anthropogenic emissions has a larger impact than climate change, causing O3 and PM2.5 levels to increase by 13 and 67 % on average in the 2050s over the main part of India, respectively. By the 2030s, secondary inorganic aerosol is predicted to become the second largest contributor to PM2.5 in India, and the largest in the 2050s, exceeding OM and dust.

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Unraveling pathways of elevated ozone induced by the 2020 lockdown in Europe by an observationally constrained regional model using TROPOMI

Atmospheric Chemistry and Physics ◽

10.5194/acp-21-18227-2021 ◽

2021 ◽

Vol 21 (24) ◽

pp. 18227-18245

Author(s):

Amir H. Souri ◽

Kelly Chance ◽

Juseon Bak ◽

Caroline R. Nowlan ◽

Gonzalo González Abad ◽

...

Keyword(s):

Transport Model ◽

Atmospheric Transport ◽

Model Simulation ◽

Surface Ozone ◽

Ozone Production ◽

Anthropogenic Emissions ◽

Nox Emissions ◽

Chemical Transport Model ◽

Voc Emissions ◽

Constrained Model

Abstract. Questions about how emissions are changing during the COVID-19 lockdown periods cannot be answered by observations of atmospheric trace gas concentrations alone, in part due to simultaneous changes in atmospheric transport, emissions, dynamics, photochemistry, and chemical feedback. A chemical transport model simulation benefiting from a multi-species inversion framework using well-characterized observations should differentiate those influences enabling to closely examine changes in emissions. Accordingly, we jointly constrain NOx and VOC emissions using well-characterized TROPOspheric Monitoring Instrument (TROPOMI) HCHO and NO2 columns during the months of March, April, and May 2020 (lockdown) and 2019 (baseline). We observe a noticeable decline in the magnitude of NOx emissions in March 2020 (14 %–31 %) in several major cities including Paris, London, Madrid, and Milan, expanding further to Rome, Brussels, Frankfurt, Warsaw, Belgrade, Kyiv, and Moscow (34 %–51 %) in April. However, NOx emissions remain at somewhat similar values or even higher in some portions of the UK, Poland, and Moscow in March 2020 compared to the baseline, possibly due to the timeline of restrictions. Comparisons against surface monitoring stations indicate that the constrained model underrepresents the reduction in surface NO2. This underrepresentation correlates with the TROPOMI frequency impacted by cloudiness. During the month of April, when ample TROPOMI samples are present, the surface NO2 reductions occurring in polluted areas are described fairly well by the model (model: −21 ± 17 %, observation: −29 ± 21 %). The observational constraint on VOC emissions is found to be generally weak except for lower latitudes. Results support an increase in surface ozone during the lockdown. In April, the constrained model features a reasonable agreement with maximum daily 8 h average (MDA8) ozone changes observed at the surface (r=0.43), specifically over central Europe where ozone enhancements prevail (model: +3.73 ± 3.94 %, +1.79 ppbv, observation: +7.35 ± 11.27 %, +3.76 ppbv). The model suggests that physical processes (dry deposition, advection, and diffusion) decrease MDA8 surface ozone in the same month on average by −4.83 ppbv, while ozone production rates dampened by largely negative JNO2[NO2]-kNO+O3[NO][O3] become less negative, leading ozone to increase by +5.89 ppbv. Experiments involving fixed anthropogenic emissions suggest that meteorology contributes to 42 % enhancement in MDA8 surface ozone over the same region with the remaining part (58 %) coming from changes in anthropogenic emissions. Results illustrate the capability of satellite data of major ozone precursors to help atmospheric models capture ozone changes induced by abrupt emission anomalies.

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Effect of changing NOx lifetime on the seasonality and long-term trends of satellite-observed tropospheric NO2 columns over China

10.5194/acp-2019-670 ◽

2019 ◽

Cited By ~ 2

Author(s):

Viral Shah ◽

Daniel J. Jacob ◽

Ke Li ◽

Rachel F. Silvern ◽

Shixian Zhai ◽

...

Keyword(s):

Transport Model ◽

Eastern China ◽

Anthropogenic Emissions ◽

Organic Nitrates ◽

Nox Emissions ◽

Chemical Transport Model ◽

Volatile Organic ◽

Tropospheric No2 ◽

Long Term Trends

Abstract. Satellite observations of tropospheric NO2 columns are extensively used to infer trends in anthropogenic emissions of nitrogen oxides (NOx ≡ NO + NO2), but this may be complicated by trends in NOx lifetime. Here we use 2004–2018 observations from the OMI satellite-based instrument (QA4ECV and POMINO v2 retrievals) to examine the seasonality and trends of tropospheric NO2 columns over central-eastern China, and we interpret the results with the GEOS-Chem chemical transport model. The observations show a factor of 3 increase in NO2 columns from summer to winter, which we explain in GEOS-Chem as reflecting a longer NOx lifetime in winter than in summer (21 h versus 5.9 h in 2017). The 2005–2018 summer trends of OMI NO2 closely follow the trends in the Multi-resolution Emission Inventory for China (MEIC), with a rise over the 2005–2011 period and a 25 % decrease since. We find in GEOS-Chem no significant trend of the NOx lifetime in summer, supporting the emission trend reported by MEIC. The winter trend of OMI NO2 is steeper than in summer over the entire period, which we attribute to a decrease in NOx lifetime at lower NOx emissions. Half of the NOx sink in winter is from N2O5 hydrolysis, which counterintuitively becomes more efficient as NOx emissions decrease due to less titration of ozone at night. Formation of organic nitrates also becomes an increasing sink of NOx as NOx emissions decrease but emissions of volatile organic compounds (VOCs) do not.

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Relative effects of open biomass and crop straw burning on haze formation over central and eastern China: modelling study driven by constrained emissions

10.5194/egusphere-egu2020-12507 ◽

2020 ◽

Author(s):

Pengfei Li ◽

Shaocai Yu ◽

Yujie Wu ◽

khalid Mehmood ◽

Liqiang Wang ◽

...

Keyword(s):

High Pressure ◽

Transport Model ◽

Eastern China ◽

Chemical Transport ◽

Ambient Air ◽

Chemical Transport Model ◽

Pressure System ◽

Crop Straw ◽

Satellite Retrievals ◽

Straw Burning

Open biomass burning (OBB) has large potential in triggering local and regional severe haze with elevated fine particulate matter (PM2.5) concentrations and could thus deteriorate ambient air quality and threaten human health. Open crop straw burning (OCSB), as a critical part of OBB, emits abundant gaseous and particulate pollutants, especially in fields with intensive agriculture, such as central and eastern China (CEC). &#160;However, uncertainties in current OCSB and other types of OBB emissions in chemical transport models (CTMs) lead to inaccuracies in evaluating their impacts on haze formations. Satellite retrievals provide an alternative that can be used to simultaneously quantify emissions of OCSB and other types of OBB, such as the Fire INventory from NCAR version 1.5 (FINNv1.5), which, nevertheless, generally underestimate their magnitudes due to unresolved small fires. In this study, we selected June in 2014 as our study period, which exhibited a complete evolution process of OBB (from June 1 to 19) over CEC. During this period, OBB was dominated by OCSB in terms of the number of fire hotspot and associated emissions, most of which were located at Henan and Anhui with intensive enhancements from June 5 to 14. OCSB generally exhibits spatiotemporal correlation with regional haze over the central part of CEC (Henan, Anhui, Hubei, and Hunan), while other types of OBB emissions had influences on Jiangxi, Zhejiang, and Fujian. Based on these analyses, we establish a constraining method that integrates ground-level PM2.5 measurements with a state-of-art fully coupled regional meteorological and chemical transport model (the two-way coupled WRF-CMAQ) in order to derive optimal OBB emissions based on FINNv1.5. It is demonstrated that these emissions allow the model to reproduce meteorological and chemical fields over CEC during the study period, whereas the original FINNv1.5 underestimated OBB emissions by 2 ~ 7 times, depending on specific spatiotemporal scales. The results show that OBB had substantial impacts on surface PM2.5 concentrations over CEC. Most of the OBB contributions were dominated by OCSB, especially in Henan, Anhui, Hubei, and Hunan, while other types of OBB emissions also exerted influence in Jiangxi, Zhejiang, and Fujian. With the concentration-weighted trajectory (CWT) method, potential OCSB sources leading to severe haze in Henan, Anhui, Hubei, and Hunan were pinpointed. The results show that the OCSB emissions in Henan and Anhui can cause haze not only locally but also regionally through regional transport. Combining with meteorological analyses, we can find that surface weather patterns played a cardinal role in reshaping spatial and temporal characteristics of PM2.5 concentrations. Stationary high-pressure systems over CEC enhanced local PM2.5 concentrations in Henan and Anhui. Then, with the evolution of meteorological patterns, Hubei and Hunan in the low-pressure system were impacted by areas enveloped in the high-pressure system. These results suggest that policymakers should strictly undertake interprovincial joint enforcement actions to prohibit irregular OBB, especially OCSB over CEC. Constrained OBB emissions can, to a large extent, supplement estimations derived from satellite retrievals as well as reduce overestimates of bottom-up methods.

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Seasonal and spatial variability of surface ozone over China: contributions from background and domestic pollution