ABSTRACT
Five different background observation sites in China are selected in this study to analyze the particle matters (PMs), including PM10, PM2.5, PM1, black carbon mass concentration (BC) and their variations in 2020. Pronounced seasonal variation is found at Daxing, Shouxian and Shenzhen sites with the highest concentration in winter and lowest in summer. At Shangri-La, the highest concentration occurs in spring, and the lowest concentration occurs in summer. At Haizhu site, the highest concentration occurs in spring and autumn, and the lowest concentration occurs in summer. The PM10, PM2.5, PM1 and BC concentrations show spatial differences, the annual average concentrations are in the range of 5.6−84.2 μg/m3, 4.3−48.0 μg/m3, 3.6−38.5 μg/m3 and 0.31−2.3 μg/m3. The mass fractions of BC in different sizes PM are also calculated, the ratios of BC to PM1 are the highest at all five sites, but they are also close to the ratios of BC to PM2.5, the ratios of BC to PM10 are the lowest. BC, PM2.5 concentrations and their ratios basically share similar diurnal pattern with two peaks at rush hour in the morning and evening respectively, but with slight differences between different sites.
