[Weekend Effect in Distributions of Particulate Matters, Main Gas Pollutants and Aerosol Size in Spring of Jiaxing].

To investigate the discrepancy of distributions of major gas pollutants and aerosol size between weekdays and weekends,trace gases( SO_2,NO_2,CO_ and O_3),PM( PM10 and PM2. 5) and aerosol spectral distributions at 10 nm-10 μm were monitored in May 2015 at Nanhu district in Jiaxing. The results showed that the gas pollutants of SO_2,NO_2,CO_ and O_3 had significant weekend effects in Jiaxing. The O_3 concentration on daytime of weekends was lower than that of weekdays. The peak of O_3 occurred at 14: 00 on weekends,which was 1 hour later than that on weekdays. The weekend effect of PM2. 5was observed to be much more obvious compared to that of PM10. The ratios of PM2. 5/ PM10 were 0. 7 and 0. 6 on weekends and weekdays,respectively. The aerosol number concentration was mostly concentrated at particle size below 500 nm,with values of 16 602 cm- 3and 23 309 cm~(-3) on weekends and weekdays. The most remarkable weekend effect was found for aerosol number concentration in nuclei mode, for surface area concentration in nuclei and coarse mode,and for mass concentration in accumulation and coarse mode. The spectra of aerosol number concentration,surface area concentration and mass concentration showed unimodal,trimodal and four-peak distributions,respectively.