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Characteristics of non-volatile and semi-volatile particulate matters in PM2.5 in Shanghai during winter and spring. |
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Abstract The tapered element oscillating microbalance (TEOM) instruments are widely used to measure the concentration of PM2.5 in China. It is found that only non-volatile particulate matters can be measured by TEOM method, while the semi-volatile particulate matters are lost by increased sampling temperature at 50℃. Thus, the PM2.5 concentrations are undermeasured. Currently, a new method of combining TEOM with FDMS (Filter Dynamic Measurement System) was developed and applied to measure both the non-volatile and the semi-volatile particulate matters in PM2.5. In this paper, the non-volatile and semi-volatile fractions in PM2.5 were measured in the suburban aera of Shanghai from Dec. 2011 to Apr. 2012. The results showed that the semi-volatile fraction accounted for 18.91% in PM2.5. NH4NO3 is an overwhelming component in the semi-volatile fraction in mega cities, therefore, additional compensation of PM2.5 measurement must be concerned in this regime. Based on the well linear correlation between compensated PM2.5 concentration and uncompensated PM2.5 concentration, the compensated concentration of PM2.5 could be calculated by the measured uncompensated PM2.5.
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Received: 01 August 2012
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