Variation of Aerosol Parameters in the Summer and Winter in Beijing

It is found that there are two peaks for the average diurnal variations of PM_(10) and N_(OPC) in the summer in Beijing, and an obvious valley can be seen between 12:30 to 15:00 for their average diurnal variation in the winter. There is one single peak for the average diurnal variation of atmospheric visibility in the summer, while there are two peaks in the winter. PM_(10) and N_(OPC) are usually lower in the summer than in the winter. The average visibility is much lower during 0:00 to 9:00 in the summer than in the winter, because of the very high relative humidity and higher number concentration of large particles (i.e. r1^25 μm) in the summer during the period.