Partic. vol. 2 no. 1 pp. 25-30 (February 2004)
doi: 10.1016/S1672-2515(07)60016-5

Analysis of particulate mass concentration, aerosol number concentration and visibility in beijing

Fengqi Yan^a, Huanling Hu^a,*, Tong Yu^b

hlhu@aiofm.ac.cn

Abstract

Particulate mass concentration (PM₁₀, PM_2.5), aerosol number concentration (N_OPC), aerosol size distribution and atmospheric visibility were simultaneously measured in Beijing in the summer and winter of 2001. From the profuse data collected, the following conclusions can be drown: (1) there are two peaks for the average diurnal variations of PM₁₀ and N_OPC in the summer, an obvious valley can be seen between 12:30 and 15:00 for their average diurnal variation in the winter; (2) there is one single peak for the average diurnal variation of atmospheric visibility in the summer, while there are two peaks in the winter; (3) PM₁₀ and N_OPC are usually smaller in the summer than those in the winter; (4) the average visibility is much lower during 00:00∼09:00 in the summer than that in the winter, because of the very high relative humidity and higher concentration of the large particles (r>1.25 μm) in the summer during the period; (5) aerosol size distributions usually depend closely on season and relative humidity at the same place.

Keywords

optical particle counter; atmospheric aerosol; atmospheric visibility; number concentration; distribution