A comparison of different chemical models for use in regional simulations of air pollution; Jaemfoerelse mellan olika kemiska modeller foer tillaempning vid regional simulering av luftfoeroreningar

摘要: Four different models for predicting photochemical oxidant formation, using different chemical simplifications, have been compared to a more complete and detailed model. Weather data for the growing season, and emission data for southern Sweden was used as a standard input for the calculations. The results were also compared using the input data with only half of the Swedish emissions of NO{sub x} and VOC. The simulated concentrations of ozone, volatile organic compounds, peroxyacethylnitrate (PAN), hydrogen peroxide, nitrogen oxides, nitric acid, hydroxyl radicale and formaldehyde have been compared during 48 hours. No significant differences between the models occurred for the simulated NO{sub x}, HNO{sub 3} and O{sub 3} profiles, although large deviations were noted for the H{sub 2}O{sub 2} and PAN simulations. These discrepancies can be attributed to the different reaction pathways used for VOC decomposition. A 50% NO{sub x} reduction in the input data, related to a decrease in the ozone concentrations of up to 6-10%, while the PAN levels decreased by 11-27%. Similarly, the model results using a halved VOC emission as input, showed a maximum ozone reduction of 2-6% and a maximum PAN reduction of 15-19%. The largest decreases in ozone and PAN were observed in a 50% emission reduction of both NO{sub x} and VOC. In this case the maximum ozone decrease was 8-13% and the corresponding PAN decrease was 27-36%. 44 refs., 20 figs, 5 tabs.