Ozone pollution over China and India: seasonality and sources

Abstract

A regional fully coupled meteorology-chemistry model, Weather Research and Forecasting model with Chemistry (WRF-Chem), was employed to study the seasonality of ozone (O 3 ) pollution and its sources in both China and India. Observations and model results suggest that O 3 in the North China Plain (NCP), Yangtze River Delta (YRD), Pearl River Delta (PRD), and India exhibit distinctive seasonal features, which are linked to the influence of summer monsoons. Through a factor separation approach, we examined the sensitivity of O 3 to individual anthropogenic, biogenic, and biomass burning emissions. We found that summer O 3 formation in China is more sensitive to industrial and biogenic sources than to other source sectors, while the transportation and biogenic sources are more important in all seasons for India. Tagged simulations suggest that local sources play an important role in the formation of the summer O 3 peak in the NCP, but sources from Northwest China should not be neglected to control summer O 3 in the NCP. For the YRD region, prevailing winds and cleaner air from the ocean in summer lead to reduced transport from polluted regions, and the major source region in addition to local sources is Southeast China. For the PRD region, the upwind region is replaced by contributions from polluted PRD as autumn approaches, leading to an autumn peak. The major upwind regions in autumn for the PRD are YRD (11 %) and Southeast China (10 %). For India, sources in North India are more important than sources in the south. These analyses emphasize the relative importance of source sectors and regions as they change with seasons, providing important implications for O 3 control strategies.

Ethylenediurea (EDU) spray effects on willows (Salix sachalinensis F. Schmid) grown in ambient or ozone-enriched air: implications for renewable biomass production

“…Due to its complex chemistry, the control of O 3 levels is challenging, and O 3 can remain at elevated concentrations even if the emissions of some O 3 precursors are highly decreased (Sicard et al 2020;Querol et al 2021;Sicard 2021). Being also affected by transboundary long-range transport (Gao et al 2020;Erickson et al 2020), which downplays national efforts to decrease O 3 concentrations, O 3 levels may remain elevated for several decades to come (Sicard et al 2017). Such elevated O 3 levels can lead to inhibited photosynthesis and suppressed woody biomass production and yields (Paoletti 2006;Karnosky et al 2007a;Koike et al 2013;Jolivet et al 2016;Li et al 2017;Cotrozzi 2021), suggesting increased risks to tree productivity (Sicard et al 2017;Feng et al 2019a;Proietti et al 2021;Sacchelli et al 2021).…”

Unprecedented Temporary Reduction in Global Air Pollution Associated with COVID-19 Forced Confinement: A Continental and City Scale Analysis

“…Massive anthropogenic emissions from these sectors have resulted in various environmental issues in terms of harmful effects on human health [9][10][11], worsened outdoor air quality [12,13], and an altered climate system [14,15]. In the list of the world's most polluted cities, most of the top 30 most polluted cities are located in Asia, especially in India, Pakistan, and China [16][17][18][19][20][21]. One of many causes leading up to outdoor air pollution is that the developing countries around the world do not adopt the standard operating protocols to run industrial units [22].…”

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“…CC BY 4.0 License. (Gao et al, 2016a(Gao et al, , 2016b(Gao et al, , 2020b(Gao et al, , 2020c) that the spatio-temporal variations of air pollutants over China could be reproduced well by WRF-Chem. WRF-Chem enables multiple options for gas phase chemistry and aerosol modules (Grell et al, 2005).…”