Study On Secondary Organic Aerosol Tracers In Summer In Ya’an

Secondary organic aerosols (SOA) could reduce visibility, change climate, hurt human health. Due to the complicate sources and the formation mechanism of the SOA and their harm to environment, it is a hot spot in the field of the atmospheric chemistry research. In this study, we chose Ya’an as the PM2.5samples collection spot and collected aerosol samples during the summer of2010. With OC-EC analysis and GC/MS analysis and IC analysis, The aerosol chemical components (aerosol mass, OC and EC), the aerosol water soluble ions, the organic carbohydrate and SOA components (mainly including oxidized isoprene productions and oxidized α-/β-pinene productions) and the concentration of the trend in urban sistrict (sichuan agricultural university campus) and suburbans district (the white MaQuan scenic spot), combining with air pollution gas (SO2, NOx, NH3,O3) and environmental climatic conditions (wind speed, temperature, humidity and so on).we discussed the influence of their concentrations. The results show that:1) In the PM2.5samples, two place show different concentrations in24h, day and night samples were form87.0.90.6,100.3ug/m3to72.3,80.0,63.3ug/m3. The two isoprene and α-/β-pinene oxidation product are appeared the same regular pattern, such as the concentrations in day samples higher than in the night;2) We had estimated not only the total mass concentration of the biogenic aerosol. OC.EC, but secondary organic carbon (SOC) as well. The SOC in the24h samples were15.4and10.1, show that there are a lot of secondary organic ingredients has formed. With GC-MS, we confirmed that there has isoprene oxidation products and α-/β-pinene oxidation products, and analyzes the changes both;3) Isoprene oxidation products and α-/β-pinene oxidation products are related to local vegetation, topography, the meteorological conditions (the wind, temperature, humidity and so on),atmospheric gases, and many other environmental factors. Among them the wind is the obvious influence with the concentration.Temperature and humidity less effect on the concentration of aerosol, OC.EC, and the concentrations of organic carbohydrates, but to SOA(isoprene oxidation products and α-/β-pinene oxidation products),temperature is an important affect factor, and the gas can influence the way of secondary organic oxidation reaction and the product kinds of secondary organic oxidation, high humidity can promote the form of secondary organic aerosol.