The Pollution Characteristics Of Peroxides And Its Influence On Aerosol Generation, In A Case Study Of Commerice-residence-traffic Region Region In Beijing

Peroxides including Hydrogen peroxide(H2O2), Methyl hydroperoxide(MHP) are secondary products of atmospheric photochemical reactions and are the reservoir and sink of free radicals., They can oxidize sulfur dioxide to sulfuric acids in aqueous phase and significantly influence the formation of acid rain and aerosols because of their strong oxidation ability and high water-solubility. The study investigated the pollution of H2O2 and MHP in atmosphere, and the effect of concentration of air pollutants such as O3, SO2, NOX, particulate matter and meteorological parameter such as temperature, relative humidity on the concentration of peroxides.The concentrations of H2O2 in atmosphere ranged from 0.02 to 3.30 ppbv with the mean of 0.70±0.59 ppbv, and the concentrations of MHP ranged from 0.05 to 1.20 ppbv with the mean of 0.11±0.11 ppbv. Compare with the concentration of peroxides on cloudy days, it was higher on sunny days. The seasonal concentrations of H2O2 were in the order of summer>spring>fall.In most cases,two peeks of H2O2 concentrations appeared during 13:00~16:00 and after 17:00 on sunny days, respectively. In about 50% cases, MHP concentrations exhibited similar diurnal variation with H2O2, and no pronounced peek appeared in the other cases. On cloudy days the concentrations of H2O2 and MHP did not show an explicit diurnal cycle.It was found that H2O2 concentrations increased with the increase of O3 concentration and temperature, reduced with the increase of PM2.5, NOX and CO concentrations. No relationshiops were observed for concentration of H2O2 and that of SO2. The relative humidity had not obverious impact on concentration of H2O2. MHP concentrations increased with the increase of O3 concentration and temperature, and did not significantly related with relative humidity and concentrations of SO2 and CO.The result of the work showed that the atmospheric concentration of peroxides was higher in afternoon than morning. The temperature and the concentration of O3 and NOX were the main factors which influence the concentration of peroxides, while the factors such as relative humidity, the concentrarion of CO and PM2.5 had insignificant effect on concentrations of peroxides.