A smog chamber made of Teflon film with a volume of approximately 2 m3 was used for the experiments of aerosol generation by photoirradiation to α-pinene-NOx -dry air system. The generated aerosol was analyzed by FT-IR, GC/MS and GC/IR. Hydroxyl, carbonyl and organonitrate functional groups were detected from the aerosol. A group of the products with a volatility lower than pinonic acid were identified with dicarboxylic acids including pinic acid (3-carboxy-2, 2-dimethylcyclobutaneacetic acid) . IR absorption of acid anhydride or cyclic ester was detected from some products. By the photooxidation of α-pinene (1.32 ppm) with NOx (0.78 ppm) , pinic acid was produced even after the consumption of α-pinene with the final formation yield of 0.74%. This suggests that pinic acid is produced from reaction of α-pinene with ozone either directly or through oxocarboxylic acid.
Concentrations of organic contaminants (hereafter abbreviated as ORCs) in cleanroom air were measured regularly since operations in a new cleanroom were started. Concentrations of ORCs in cleanroom air gradually decreased and attained steady state values after six months. The removal efficiency of a chemical filter for total ORCs was significantly reduced with time, however the efficiencies for di (2-ethylhexyl) phthalate (DOP) , di (isobutyl) phthalate and low molecular weight cyclosiloxanes (LMCSs) remained at a sufficiently high value for three years. The sticking probabilities of DOP and Trichloroethylphosphate onto Si surface were estimated to be 1 × 10-2 and 5 × 10-3 from the concentrations of ORCs in the air and the masses of ORCs deposited on Si wafers.
Air pollution in all regions of China is recognized as smoke pollution type. Coal combustion is the largest source of artificial particulate matter in the atmosphere. Especially, acidic aerosols could cause acidic precipitation with air pollution. The influence of acidic precipitation is continuously increasing in China. Therefore, we are studying a coal-biomass briquette technique as an effective control technique to reduce sulfur dioxide and other pollutants released from coal combustion. In order to understand the reduction of particulate matter and acidic aerosol emission with the bio-briquette technique, the acidity and the acid-neutralizing capacity of aerosols released from raw coal and bio-briquette combustion were measured. This study showed that H+ concentration in aerosols from bio-briquette combustion is reduced by 43∼85 % compared to the raw-coal combustion, and HCl, SO2 and dust emissions are also reduced by 26∼61, 82∼87 and 55∼83 %, respectively. It is concluded that bio-briquette technique not only reduces the pollutants emitted from coal combustion, but also lowers the acidity of particulate matter released from it.