Climate-driven deterioration of future ozone pollution in Asia predicted by machine learning with multi-source data

Abstract

Abstract. Ozone (O3) is a secondary pollutant in the atmosphere formed by photochemical reactions that endangers human health and ecosystems. O3 has aggravated in Asia in recent decades and will vary in the future. In this study, to quantify the impacts of future climate change on O3 pollution, near-surface O3 concentrations over Asia in 2020–2100 are projected using a machine learning (ML) method along with multi-source data. The ML model is trained with combined O3 data from a global atmospheric chemical transport model and real-time observations. The ML model is then used to estimate future O3 with meteorological fields from multi-model simulations under various climate scenarios. The near-surface O3 concentrations are projected to increase by 5 %–20 % over South China, Southeast Asia, and South India and less than 10 % over North China and the Gangetic Plains under the high-forcing scenarios in the last decade of 21st century, compared to the first decade of 2020–2100. The O3 increases are primarily owing to the favorable meteorological conditions for O3 photochemical formation in most Asian regions. We also find that the summertime O3 pollution over eastern China will expand from North China to South China and extend into the cold season in a warmer future. Our results demonstrate the important role of a climate change penalty on Asian O3 in the future, which provides implications for environmental and climate strategies of adaptation and mitigation.

Regional and sectoral contributions of NOx and reactive carbon emission sources to global trends in tropospheric ozone during the 2000–2018 period

“…Further studies could investigate the tagged contributions to the trends in the spatial and seasonal distribution of ozone (e.g., Wang et al 2022, Fiore et al, 2022, which may help us enhance our understanding of various processes responsible for these trends. While previous studies used the TOAST tagging to understand the trends in surface ozone over United States (e.g., Li et al, 2023a), free tropospheric ozone over Southeast Asia (e.g., Li et al, 2023b) and over East Asia in future scenarios (e.g., Hou et al, 2023), we recommend such studies be extended to other regions of interest. Comparison of smaller time periods (2000-2010, and 2010-2018) could also be considered to understand the contrasting effect of increasing and decreasing East Asian precursor emissions respectively.…”

Meteorological characteristics of severe ozone pollution events in China and their future predictions

“…Many studies have reported that future climate change will have significant influences on O3 pollution in China through changing meteorological factors (e.g., Li et al, 2023;Wang et al, 2022). Here, the frequencies of extreme months with high T2m and low RH and the frequencies of extreme months with SLP and 500 hPa GPH that have moderate to high correlation to those in the polluted months in the four regions of China, under the sustainable (SSP1-2.6) and high forcing (SSP5-8.5) scenarios during 2021-2100 from CMIP6 multi-model results, are presented in Figures 9 and 10, respectively.…”

Ozone Pollution in China Affected by Climate Change in a Carbon Neutral Future as Predicted by a Process‐Based Interpretable Machine Learning Method

“…In addition to precursor emissions, recent evidences have pointed out that variations in meteorological parameters due to climate change also play vital roles in influencing O 3 concentrations (Doherty et al, 2013; Fu & Tian, 2019; Gong & Liao, 2019; Jacob & Winner, 2009; Kavassalis & Murphy, 2017; H. Li et al, 2023; M. Li et al, 2023; Lu, Zhang, Chen, et al, 2019; Lu, Zhang, & Shen, 2019; P. Wang et al, 2022; Yang et al, 2014, 2022; Zhou et al, 2022). Several studies have estimated future O 3 changes in China under different scenarios.…”

“…H. Li et al. (2023) predicted a strong O 3 ‐climate penalty over eastern China and suggested that the future climate change would expand the summertime O 3 pollution from northern China to southern China and extend it into the cold season. To mitigate risks associated with climate change, the Chinese government has committed to reach peak carbon emissions before 2030 and achieve carbon neutrality by 2060.…”