Analysis on the Characteristics and Influencing Factors of Ozone in Fuzhou, China Using the Wavelet Analysis

ABSTRACT

In recent years, ozone (O₃) pollution has become a major and growing air pollution problem in China. In this study, the O₃ concentration monitoring data, meteorological parameters and traffic data from Fuzhou were collected, the wavelet transform method was used to analyze the variation characteristics of O₃ concentration and the correlation between O₃ concentration and influencing factors. The annual variation characteristics are shown as follows: high value areas of O₃ concentration appeared in spring and summer; the significant fluctuations were concentrated in March to April, June to July and September; and the mutation days indicated the possible relationships between O₃ concentration and meteorological parameters. The correlation analysis showed that O₃ concentration had a significant positive correlation with temperature and sunshine duration, while it had a negative correlation with relative humidity, precipitation and air pressure. Additionally, the O₃ concentration increased in lower wind speed and fluctuated in higher wind speed. Furthermore, precursors (NO_x and CO) also had a significant negative correlation with O₃, and the fluctuations of precursors on working day were larger than the rest day. The traffic parameters (vehicle flow, vehicle speed and traffic flow density) were closely correlated to O₃ concentration, the vehicle speed decreased with the increase of vehicle flow and traffic flow density in peak time, leading to an increase in precursors emissions from vehicle exhaust. Notably, there was a significant “weekend effect” between precursors, vehicle flow and O_3.