Lower to middle (0.5-3.0 km altitude) troposphericaerosols (PM
2.5) collected by
aircraft over inland and eastcoastal China were, for the first time, characterized fororganic molecular compositions to understand anthropogenic,natural, and photochemical contribution to the air quality.
n-Alkanes, fatty acids, sugars, polyacids are detectedas major compound
classes, whereas lignin and resinproducts, sterols, polycyclic aromatic hydrocarbons, andphthalic acids are minor species. Average concentrationsof all the identified compounds excluding malic acidcorrespond to 40-50% of those reported on the groundsites. Relative abundances of secondary organic aerosol(SOA) components such as malic acid are much higher inthe
aircraft samples, suggesting an enhanced photochemicalproduction over China. Organic carbon (OC) concentrationsin summer (average, 24.3
![](/images/entities/mgr.gif)
g m
-3) were equivalent tothose reported on the ground sites. Higher OC/EC (elementalcarbon) ratios in the summer
aircraft samples alsosupport a significant production of SOA over China. Highloadings of organic aerosols in the Chinese troposphere maybe responsible to an intercontinental transport of thepollutants and potential impact on the regional and globalclimate changes.