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List of Abstracts 138episodes is of extreme importance since the government has to take actions in advance to prevent excessiveair quality deterioration. The forecasting system is based on the fact that during these episodes a highcorrelation (over 0.95) is observed between measurements of elevated levels of PM10/PM2.5 and carbonmonoxide (CO). Thus, by accurately forecasting CO, which behaves closely to a tracer on this scale, a PMestimate can be made without involving an aerosol-chemistry model. This simplification is convenient to theauthorities that responsible for operational air quality forecast since it reduces computing resources.However the very stable nocturnal conditions over steep topography that creates the maximum inconcentrations are hard to represent by models. The new system is based on the WRF-Chem model withoptimum settings, determined through extensive testing, that best describe both meteorological and airquality measurements. Some of the important configurations choices relate to the boundary layer (PBL) andcloud schemes, which can have an effect on the radiative feedbacks that modify the nocturnal PBL. Finally,a forecast for the whole winter period for year 2008 is performed, evaluating the forecasting performanceand comparing it to previous prediction models.P-Transformation.30 ID:4330 10:30Aircraft Measurement of Polar Organic Compounds in PM10 Aerosols over Central China:Contributions of Primary Emissions and Secondary PhotooxidationPingqing Fu 1 , Kimitaka Kawamura 1 , Shiro Hatakeyama 2 , Akinori Takami 2 , Hong Li 3 , Wei Wang 31 Institute of Low Temperature Science, Hokkaido University, Japan2 National Institute for Environment Studies, Japan3 Chinese Research Academy of Environmental Sciences, ChinaContact: pqfu@pop.lowtem.hokudai.ac.jpAtmospheric aerosol samples (PM10) were collected by aircraft at low-middle altitudes (0.5-3.0 km) overCentral East to West China during summer 2003 and spring 2004. They were analyzed for different types ofpolar organic compounds using GC/MS. More than 80 species were detected in the aerosols and groupedinto different compound classes, including fatty acids, n-alcohols, sugar compounds, sterols, hydroxy-/polyacids, organic nitrogen compounds (oxamic acid and urea), and biogenic secondary organic aerosol(SOA) tracers for the photooxidation of isoprene (e.g., 2-methyltetrols), α/β-pinene (e.g., pinic acid), and β-caryophyllene (β-caryophyllinic acid). Total concentrations of the identified organics were 746-3537 ng m-3(average 1986 ng m-3) in summer versus 223-1339 ng m-3 (519 ng m-3) in spring. Fatty acids are the mostabundant compound class, followed by n-alcohols, sugar compounds and biogenic SOA tracers. The totalconcentrations of biogenic SOA tracers are higher in summer (5.80-153 ng m-3, average 50.8 ng m-3) thanin spring (5.76-66.8 ng m-3, 22.2 ng m-3). This difference is especially significant for isoprene SOA tracers(41.6±38.0 ng m-3 in summer versus 14.3±10.5 ng m-3 in spring). On the contrary, concentrations of α/βpineneand β-caryophyllene SOA tracers are similar between spring and summer. Interestingly, a strongcorrelation (R2=0.83) was found between levoglucosan and β-caryophyllinic acid for the spring sampleswhereas no correlation (R2=0.17) for the summer samples, indicating that biomass burning could be a mainsource of β-caryophyllinic acid over Central China during springtime. Total concentrations of organicnitrogen compounds are comparable to those of biogenic SOA tracers without any differences betweenspring and summer. The urea concentrations decreased with an increase in the altitude, suggesting that itmay be emitted from the anthropogenic sources on the ground surface. This study demonstrates that bothbiogenic SOA and organic nitrogen are significant components of organic aerosols over Central China.iCACGP-IGAC 2010 14 July, 2010