Seasonal variation of size-fractionated particulate matter in residential houses in urban area in Vietnam: relationship of indoor and outdoor particulate matter and mass size distribution

¹ Deparment of Environmental Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8540, Japan
² School of Environmental Science and Technology, Hanoi University of Science and Technology, 1 Dai Co Viet, Hanoi, Vietnam
³ Graduate School of Sci. and Eng., Saitama University, 255 Shimo-Okubo, Sakura, Saitama 338-8570, Japan
⁴ Center for Health and Environmental Risk Research, National Institute for Environmental Studies, Tsukuba 305-8506, Japan

^* Corresponding author: yoneda@risk.env.kyoto-u.ac.jp

Abstract

The study aims to determine the concentration, size distribution and analyze the relationship of indoor and outdoor particles in urban area, in Vietnam. One thousand two hundred daily samples of PM_0.1, PM_0.1-0.5, PM_0.5-1, PM_1-2.5, PM_2.5-10, PM_>10 were taken simultaneously at four residential houses in summer and winter by nano sampler (Model 3182, Kinomax). The average concentrations of indoor PM_0.1, PM_0.5, PM₁, PM_2.5 and PM₁₀ were in range of 5.3-8.9 μg/m³; 10.8-20.1μg/m³; 20.5-47.6 μg/m³; 33.7-105.9 μg/m³ and 44.7-135.0 μg/m³ among four houses, respectively. The concentrations of outdoor PM_2.5, PM₁₀ were considerately higher than those of indoor PM, whereas negligible differences on concentrations of PM_0.1, PM_0.5 and PM₁ were observed. The significantly seasonal variation was observed for indoor PM₁, PM_2.5 and PM₁₀, but not for PM_0.1 and PM_0.5. Majority of indoor fractions were origin from outdoor sources. Unimodal distributions of indoor particles determined the super-micron size (1 to 2.5 μm) with highest concentration and PM_<0.5 and PM_>10 with lowest concentration. Fine particles with interval sizes (PM_0.5-1 and PM_1-2.5) contributed to the predominance to coarse particles in both indoors and outdoors, suggesting serious threat on human health.