Evidence for Coordinated Control of PM<sub>2.5</sub> and O<sub>3</sub>: Long-Term Observational Study in a Typical City of Central Plains Urban Agglomeration
Fine particulate matter (PM<sub>2.5</sub>) and Ozone (O<sub>3</sub>) pollution have emerged as the primary environmental challenges in China in recent years. Following the implementation of the Air Pollution Prevention and Control Action Plan, a substantial decline in PM<s...
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| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2025-04-01
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| Series: | Toxics |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2305-6304/13/5/330 |
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| Summary: | Fine particulate matter (PM<sub>2.5</sub>) and Ozone (O<sub>3</sub>) pollution have emerged as the primary environmental challenges in China in recent years. Following the implementation of the Air Pollution Prevention and Control Action Plan, a substantial decline in PM<sub>2.5</sub> concentrations was observed, while O<sub>3</sub> concentrations exhibited an increasing trend across the country. Here, we investigated the long-term trend of O<sub>3</sub> from 2015 to 2022 in Xinxiang City, a typical city within the Central Plains urban agglomeration. Our findings indicate that the hourly average O<sub>3</sub> increased by 3.41 μg m<sup>−3</sup> yr<sup>−1</sup>, with the trend characterized by two distinct phases (Phase I, 2015–2018; Phase II, 2019–2022). Interestingly, the increasing rate of O<sub>3</sub> concentration in Phase I (7.89 μg m<sup>−3</sup>) was notably higher than that in Phase II (2.89 μg m<sup>−3</sup>). The Random Forest (RF) model was employed to identify the key factors influencing O<sub>3</sub> concentrations during the two phases. The significant dropping of PM<sub>2.5</sub> in Phase I could be responsible for the O<sub>3</sub> increase. In Phase II, the reductions in nitrogen dioxide (NO<sub>2</sub>) and unfavorable meteorological conditions were the major drivers of the continued increase in O<sub>3</sub>. The Observation-Based Model (OBM) was developed to further explore the role of PM<sub>2.5</sub> in O<sub>3</sub> formation. Our results suggest that PM<sub>2.5</sub> can influence O<sub>3</sub> concentrations and the chemical sensitivity regime through heterogeneous reactions and changes in photolysis rates. In addition, the relatively high concentration of PM<sub>2.5</sub> in Xinxiang City in recent years underscores its significant role in O<sub>3</sub> formation. Future efforts should focus on the joint control of PM<sub>2.5</sub> and O<sub>3</sub> to improve air quality in the Central Plains urban agglomeration. |
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| ISSN: | 2305-6304 |