Effects of meteorology and emission reduction measures on air pollution in Beijing during heating seasons

摘要

Beijing implemented five-year clean air plan during 2013–2017, and realized the continuous improvement of air quality in the whole city year by year. In this study, the MK (Mann-Kendall) test and KZ (Kolmogorov-Zurbenko) filtering analysis method were applied to evaluate the variations of PM2.5 concentration at different sites in Beijing before and after the filtering meteorological conditions. The results showed that the averaged PM2.5 concentrations in five sites decreased by 29.82% after filtering weather conditions, which was significantly lower than the average decrease rate (33.61%) of the original data. The emissions by human activities contributed about 69–94% to the decreased PM2.5 concentrations during 2013–2017?at different sites in Beijing while the meteorological conditions contributed not more than 31% indicating the leading role of the emission reduction measures in the air quality improvement in Beijing. Contrary to the monthly averaged trends, the original PM2.5 concentrations in heating seasons during 2013–2016 did not decrease obviously and not passed the significant test (α = 0.1) due to the unfavor weather conditions which always aggravated degree and duration of air pollution. In order to further improve air quality, emission reduction measures such as reducing coal combustion, reducing oil consumption, controlling vehicles, emissions reduction, and cleaning dust should be continuously promoted.