The impact of fireworks control on air quality in four Northern Chinese cities during the Spring Festival

摘要

Online measurements for chemical components in PM2.5 (particulate matter with an aerodynamic diameter less than 2.5 mu m) were carried out in Qinhuangdao (QHD), Tangshan (TS), Shijiazhuang (SJZ), and Zhengzhou (ZZ), China, from December 14, 2016 to February 2, 2017 to assess the impact of the fireworks control on air quality during the Spring Festival. Pre-fireworks, fireworks, and post-fireworks periods were all assessed. Results show that average concentrations of PM2.5 during fireworks periods were in the following order of SJZ ZZ TS QHD. Fireworks displays have great impacts on concentrations of K+, SO42-, Cl, Mg2+, and OC. According to results of PM2.5 source apportionment, fireworks were the largest PM2.5 source during fireworks periods in QHD, TS, SJZ, and ZZ, accounting for 68.9%, 53.8%, 61.1%, and 51.0% of PM2.5, respectively. This result was similar to the result of the relative ratio method (68.6% in QHD, 57.2% in TS, 63.0% in SJZ, 53.9% in ZZ). Based on results of PM2.5 source apportionment, the contribution of fireworks from 19:00 on January 27 to 8:00 on January 28 to PM2.5 in ZZ (44.1%) was the lowest in comparison with QHD (75.7%), TS (66.0%), and SJZ (63.8%), which can be ascribed to stringent fireworks control measures in ZZ. Although fireworks displays were banned in QHD and SJZ during the Spring Festival, contributions of fireworks to PM2.5 in these two cities were higher or slightly lower than that of TS during the special period when fireworks were allowed to be set off in TS, indicating that no stringent measures were taken to effectively control fireworks displays in QHD and SJZ. These results highlight the necessity of limiting fireworks emissions during the Spring Festival.