Spatiotemporal Distribution of PM2.5 and O3 and Their Interaction During the Summer and Winter Seasons in Beijing, China

Hui Zhao,Youfei Zheng,Chen Li

doi:10.3390/su10124519

Abstract

This study analyzed the spatiotemporal variations in PM2.5 and O3, and explored their interaction in the summer and winter seasons in Beijing. To this aim, hourly PM2.5 and O3 data for 35 air quality monitoring sites were analyzed during the summer and winter of 2016. Results suggested that the highest PM2.5 concentration and the lowest O3 concentration were observed at traffic monitoring sites during the two seasons. A statistically significant (p < 0.05) different diurnal variation of PM2.5 was observed between the summer and winter seasons, with higher concentrations during daytime summer and nighttime winter. Diurnal variations of O3 concentrations during the two seasons showed a single peak, occurring at 16:00 and 15:00 in summer and winter, respectively. PM2.5 presented a spatial pattern with higher concentrations in southern Beijing than in northern areas, particularly evident during wintertime. On the contrary, O3 concentrations presented a decreasing spatial trend from the north to the south, particularly evident during summer. In addition, we found that PM2.5 concentrations were positively correlated (p < 0.01, r = 0.57) with O3 concentrations in summer, but negatively correlated (p < 0.01, r = −0.72) with O3 concentrations in winter.

Highlights

In recent years, serious air pollution has become one of the most important environmental problems along with the development of society and economy, especially in economically developed cities, such as Beijing, Shanghai, Guangzhou, and other big cities [1]
We found that PM2.5 concentrations in Beijing were lower in summer than in winter, while O3 concentrations were higher in summer than in winter
The results showed that PM2.5 concentrations were significantly lower (p < 0.05) in summer than in winter, while O3 concentrations were significantly higher (p < 0.05) in summer than in winter

Summary

Introduction

Serious air pollution has become one of the most important environmental problems along with the development of society and economy, especially in economically developed cities, such as Beijing, Shanghai, Guangzhou, and other big cities [1]. In February 1988, the air pollution index (API), based on the concentrations of three atmospheric pollutants, namely total suspended particles (TSP), sulfur dioxide (SO2), and nitrogen dioxide (NO2), was introduced to assess the status of ambient air quality in China. On 5 June 2000, the China National Environmental Monitoring Center began to report API, defined according to the National Ambient Air Quality Standard (NAAQS-China, GB3095-1996) [12], by considering particulate matter (PM10), sulfur dioxide (SO2), and nitrogen dioxide (NO2). From 18 January 2013, the Beijing municipal government has promulgated the new National Ambient Air Quality Standards (NAAQS-China, GB3095-2012) [13], and publicized real time monitoring data of Air Quality Index (AQI) and six major atmospheric pollutants (PM2.5, O3, PM10, CO, NO2, and SO2).

Methods

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Discussion

Conclusion