Spatiotemporal variations and risk assessment of ambient air O3, PM10 and PM2.5 in a coastal city of China

Rapid industrialization and urbanization has created significant air pollution problems that have recently begin to impact the lives and health of human beings in China. This study systematically investigated the spatiotemporal variations and the associated health risks of ambient O-3, PM10 and PM2.5 between 2016 and 2019. The relationships between the target air pollutants and meteorological conditions were further analyzed using the Spearman rank correlation coefficient method. The results demonstrated that the annual mean concentrations of PM10 and PM2.5 experienced a decreasing trend overall, and PM2.5 significantly decreased from 1.54 mu g/m(3) in 2016 to 1.48 mu g/m(3) in 2019. In contrast, the annual mean concentrations of O-3 were nearly constant during the study period with a slight increasing trend. The pollutants exhibited different seasonal variations and cyclical diurnal variations. The most highest O-3 pollution was seen in spring and summer, while spring and winter were the seasons with the most PM10 and PM2.5 pollution. The highest concentrations of O-3 appeared in periods of strong solar radiation intensity and photochemical reactions. The highest concentrations of PM10 and PM2.5 appeared at commuting time. The pollutant concentrations were significantly affected by meteorological conditions. Finally, the non-carcinogenic risks from exposure to O-3, PM10 and PM2.5 were at an acceptable level (HI < 0.96) and O-3 accounted for similar to 50% of the total non-carcinogenic risks. However, PM2.5 posed highly carcinogenic risks (2.5 x 10(-4) < CR < 1.6 x 10(-1)) and O-3 exposure showed high potential ecological impacts on vegetation (AOT40: 23.3 ppm-h; W126: 29.0 ppm-h).