Air pollution and its influential factors in China's hot spots

Air pollution has existed for many decades in China. Since 2013, the indexes of air quality (hourly average mass concentrations of particulate matters (PM), sulfur dioxide (SO2), and nitrogen dioxide (NO2)) have been released to the public for real-time scrutiny and pollution research. This study aimed to explore the temporal trends and spatial differences in air pollution and the impacts of macro influential factors on four pollutants in five hot spots in China. Spatiotemporal variations were analyzed for ambient PM2.5, PM10, SO2, and NO2, and their ratios from 2011 to 2014. We used a panel data model (2004-2012) to quantify the effect of four crucial factors (selected by correlation analysis) on ambient PM2.5. The results showed that PM exceeded the national standards throughout the country. Most pollutants had decreasing trends after 2013 and southern China had less air pollution. Moreover, macro influential factors had different effects on various pollutants among the hot spots. GDP and private cars were significant positive factors for PM2.5, and the contribution of energy consumption was also significant. Hence, effective measures which considering economic leverage, transportation and energy usage for pollutant reduction and air quality improvement should be further implemented and take regional heterogeneity into consideration. (C) 2018 Published by Elsevier Ltd.