Size distribution of particles collected by passive sampler

Airborn particulate matters were sampled by two duplicate glass slides coated with thin layer of vaseline laid at the bottom of sampling cylinder of passive sampler for collecting both gaseous and particulate phase semi-volatile organic pollutant. Their size distribution was analyzed and found to be influenced by wind speed and coverage of the fine-screen-mesh (300 mesh) wrapping around the outside of sampling cylinder. In a windless (indoor) and semi-static windy conditions (sealed courtyard), diffusion of coarse particles (>50 μm) was reduced effectively by covering sampling cylinder with the fine-screen-mesh, and accumulated size distribution curve of PM₁₀ was similar with those collected by an active size-fractionated sampler (cascade impactor). In windy conditions (outdoor), coarse particles entered the sampling cylinder randomly, which is independent with wind speed, while the percentage of fine particulate with size of 3-5 μm decreased and those with size of 6-9 μm increased significantly.