| In this paper, we collected the PM2.5 real time mass concentration dates and filter samples using a TEOM 1400a ambient particulate monitor at the station point of Xi'an University of Architecture and Technology during the period of Dec 2009 to Nov 2010. In this study, the characteristics of the annual, months and high-resolution diurnal variations of PM2.5 mass concentration and its relationship with meteorological was analyzed. It also analyzes the characteristics of carbonaceous aerosol of different seasons.The annual average concentration of PM2.5 was 90.5μg/m3 during the study period. The time series of PM2.5 concentration is obvious. Winter and autumn variations range are widely than other seasons. In July, the average PM2.5 concentration is lowest of the year with the concentration of 61.37μg/m3, while January is the highest PM2.5 concentration of 143.29μg/m3. It seems that the more rainfall has the lower PM2.5 concentration.The diurnal cycle of PM2.5 concentrations in four seasons are all display evident bi-modal patterns. Traffics pollutions have more influence on the PM2.5 of the study station point. In the afternoon, the PM2.5 concentration decline obviously, in the afternoon, PM2.5 displays low concentration. So the high temperature, low RH, high wind speed in the afternoon can make contribute to dilute the particular pollutions. A lot of fireworks during spring festival days can cause serious PM2.5 pollution in a short time. Sand weather in spring can also cause serious PM2.5 pollution.The annual average OC and EC concentrations are 23.04μg/m3 and 6.15μg/m3 respectively. in winter , the OC and EC concentrations are higher than other seasons. The annual average TCA concentration during the study period is 43.01μg/m3, it account 43.5% of PM2.5. TCA is the main component of PM2.5.The diurnal cycle of carbonaceous aerosol in four seasons also display bi-modal patterns. OC various higher than EC and WSOC. In winter, spring and summer, OC concentration display max value during 9:0012:00, while in autumn, OC concentration display max value during 21:0023:00. OC/EC value always displays lower value during traffic times, but in afternoon displays higher value.In the whole year, OC and EC have good correlation, the OC and EC in Xi'an has the similar source. WSOC and OC display good correlation, WSOC and OC has the similar source. WSOC and EC is not obvious than OC, so the source of WSOC and EC may be some different. |
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