VARIATION OF AIRBORNE PARTICULATE MATTER IN THE SUBURBAN AREA OF QINGDAO, CHINA

Particulate matter of different sizes has various sources and affects the environment and human health differently, so it is extremely important to study the characteristics of particles with different diameters in order to deeply understand the pollution situation and establish reasonable policies. In this paper, parallel measurements of particle mass concentration (TSP, PM10), size-segregated particle number concentration and meteorological parameters are conducted at a suburban background site in Qingdao, China, during the summer period of 2012. Their diurnal variations and dependencies on meteorology are investigated. The calculated mass concentrations of TSP and PK10 are 92.0 mu g/m(3) and 114.8 mu g/m(3), respectively. It is also found that the average particle number concentrations of total particles (0.3-10 mu m), sub-micrometer particles (0.3-0.5 mu m and 0.5-1.0 mu m), fine particles (1.0-3.0 mu m) and coarse particles (3.0-5.0 mu m and 5.0-10 mu m) are 4.5x10(6) particles/m(3), 4.3x10(6) particles/m(3), 1.0x10(5) particles/m(3) and 3.9x10(4) particles/m(3), respectively. In addition, the average diurnal variations of total and sub-micrometer particles show unimodal distribution with the peak value at 7:00 (a.m.). Nevertheless, the distribution of fine and coarse particles is bimodal with another peak at 17:00. As for the meteorological parameters, air temperature and relative humidity exert little effect on particle mass and number concentrations, whereas wind speed and wind direction strongly affect the particle concentrations, especially for the size-segregated particle number concentration in the suburban area of Qingdao.