Toward Better and Healthier Air Quality: Global PM2.5 and O3 Pollution Status and Risk Assessment Based on the New WHO Air Quality Guidelines for 2021

Jianhua Liu; Chao He; Yajun Si; Bin Li; Qian Wu; Jinmian Ni; Yue Zhao; Qixin Hu; Shenwen Du; Zhendong Lu; Jiming Jin; Chao Xu

doi:10.1002/gch2.202300258

Toward Better and Healthier Air Quality: Global PM_2.5 and O₃ Pollution Status and Risk Assessment Based on the New WHO Air Quality Guidelines for 2021

Glob Chall. 2024 Mar 26;8(4):2300258. doi: 10.1002/gch2.202300258. eCollection 2024 Apr.

Authors

Jianhua Liu^{1

2}, Chao He^{1

2}, Yajun Si³, Bin Li^{1

2}, Qian Wu⁴, Jinmian Ni^{1

2}, Yue Zhao^{1

2}, Qixin Hu^{1

2}, Shenwen Du^{1

2}, Zhendong Lu⁵, Jiming Jin^{1

2}, Chao Xu^{6

7}

Affiliations

¹ College of Resources and Environment Yangtze University Wuhan 430100 China.
² Hubei Key Laboratory of Petroleum Geochemistry and Environment Yangtze University Wuhan 430100 China.
³ College of Water Resources and Architectural Engineering Northwest A&F University Yangling Shaanxi 712100 China.
⁴ School of Resource and Environmental Science Wuhan University Wuhan Hubei 430079 China.
⁵ Interdisciplinary Graduate Program in Informatics The University of Iowa Iowa City IA 52242 USA.
⁶ College of Resource and Environment Xinjiang Agricultural University Urumqi 830052 China.
⁷ Xinjiang Key Laboratory of Soil and Plant Ecological Processes Urumqi 830052 China.

Abstract

To reduce the high burden of disease caused by air pollution, the World Health Organization (WHO) released new Air Quality Guidelines (AQG) on September 22, 2021. In this study, the daily fine particulate matter (PM_2.5) and surface ozone (O₃) data of 618 cities around the world is collected from 2019 to 2022. Based on the new AQG, the number of attainment days for daily average concentrations of PM_2.5 (≤ 15 µg m^-3) and O₃ (≤ 100 µg m^-3) is approximately 10% and 90%, respectively. China and India exhibit a decreasing trend in the number of highly polluted days (> 75 µg m^-3) for PM. Every year over 68% and 27% of cities in the world are exposed to harmful PM_2.5 (> 35 µg m^-3) and O₃ (> 100 µg m^-3) pollution, respectively. Combined with the United Nations Sustainable Development Goals (SDGs), it is found that more than 35% of the world's cities face PM_2.5-O₃ compound pollution. Furthermore, the exposure risks in these cities (China, India, etc.) are mainly categorized as "High Risk", "Risk", and "Stabilization". In contrast, economically developed cities are mainly categorized as "High Safety", "Safety", and "Deep Stabilization." These findings indicate that global implementation of the WHO's new AQG will minimize the inequitable exposure risk from air pollution.

Keywords: SDGs; WHO's new AQG; air pollution; exposure risk; global.