Affiliations: Institute of Urban Meteorology, China Meteorological
Administration, Beijing 100089, China | State Joint Key Laboratory of Environmental Simulation
and Pollution Control, College of Environmental Sciences, Peking University,
Beijing 100871, China | Beijing Meteorological Information and Network Center,
Beijing 100089, China
Abstract: The pollution of particulate matter less than 2.5μm (PM2.5) is a
serious environmental problem in Beijing. The annual average concentration of
PM2.5 in 2001 from seasonal monitor results was more than 6 times that of the
U.S. national ambient air quality standards proposed by U.S. EPA. The major
contributors to mass of PM2.5 were organics, crustal elements and sulfate. The
chemical composition of PM2.5 varied largely with season, but was similar at
different monitor stations in the same season. The fine particles (PM2.5) cause
atrnospheric visibility deterioration through light extinction. The mass
concentrations of PM2.5 were anti-correlated to the visibility, the best fits
between atmospheric visibility and the mass concentrations of PM2.5 were
somehow different: power in spring, exponential in summer, logarithmic in
autumn, power or exponential in winter. As in each season the meteorological
parameters such as air temperature and relative humidity change from day to
day, probably the reason of above correlations between PM2.5 and visibility
obtained at different seasons come from the differences in chemical
compositions of PM2.5.
Keywords: PM2.5, atmospheric urban aerosol, air pollution, meteorological factor, visibility
