Abstract
With the ground-level ozone pollution problem increasingly prominent in recent years in China, it is particularly important in basic researches on ozone contamination characteristics. In this study, 13 cities in Beijing-Tianjin-Hebei (BTH) area were examined to determine the characteristics of surface ozone (O3) from 2015 to 2018. Due to the photochemical oxidation of ozone precursors (such as nitrogen oxides and carbon monoxide) along with the presence of sunlight and characteristics of local emission sources, the O3 and oxidant (OX) concentrations showed obvious seasonal variation and daily variation. It implicated that the O3 concentrations reached the maximum during summer. The concentrations of O3 were higher at daytime than those measured at nighttime. The ozone weekend effect was estimated by the difference and deviation, which exhibited that the difference between weekday and weekend were related to the concentrations of ozone precursors and PM, vehicle emissions, and solar radiation. Moreover, the O3 concentrations decreased with the increase of other air pollutants by correlation analysis. The ozone pollution was easily formed at light and moderate polluted periods when compared to other air quality levels.
Highlights
Surface ozone (O3 ) is a secondary air pollutant
It is subjected to solar radiation and its precursors which are nitrogen oxides (NOx), volatile organic compounds (VOCs), and carbon monoxide (CO) [12,13,14,15,16,17,18,19,20,21]
The concentrations had increased by over 50% from 2015 to 2018 and 3 showed average annual concentrations of O3 in BTH area
Summary
Surface ozone (O3 ) is a secondary air pollutant. Ozone is the primary photochemical pollutant in urban polluted air. It is subjected to solar radiation and its precursors which are nitrogen oxides (NOx), volatile organic compounds (VOCs), and carbon monoxide (CO) [12,13,14,15,16,17,18,19,20,21]. Nitrogen oxide and carbon monoxide are mainly from vehicle exhaust emissions and fossil fuel burning [22,23,24]. Concentration distributions of volatile organic compounds are associated with biomass burning, fossil fuel burning, process emission, solvent source, and traffic emission [25,26,27,28]. Wang et al [5] found that O3 pollution was affected by the transport or its Atmosphere 2020, 11, 130; doi:10.3390/atmos11020130 www.mdpi.com/journal/atmosphere
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