Estimation of the contribution of secondary organic aerosol to PM2.0 concentration in aircraft cabins

Ozone (O3) and many kinds of reactive organic compounds (ROGs) are commonly found in aircraft cabins. Thus the secondary organic aerosol (SOA) which form as the products of oxidative reactions with ROGs may be an important potential source of fine particles in aircraft cabins. This study aims to estimate the contribution of SOA to the concentration of PM2.0 (particles with aerodynamic diameter less than 2.0 μm) in aircraft cabins. Based on the measurements of O3 and ROGs concentration in the aircraft cabins of five flights in China, a SOA formation model was employed to estimate the concentration of SOA generated from the oxidation of ROGs. O3 concentration, the fraction of organic aerosol (OA) mass (sum of organic aerosol components from outdoor sources (OOA), organic aerosol components emitted by primary indoor sources (POA) and SOA), the concentration of the PM2.0 and the deposition rate of particle matter (PM) that affecting SOA generation were investigated. The results show that the SOA contribution could reach to 56% in some cases, the average SOA contribution ranges from zero to 20% for the five studied flights. The O3 concentration, POA mass fraction and the concentration of PM2.0 are all important factors influencing the SOA contribution. The deposition rate of PM has little effect on the SOA generation.