Estimation of vehicular emission inventories in China from 1980 to 2005

Multi-year inventories of vehicular emissions at a high spatial resolution of 40 km×40 km were established in China using the GIS methodology for the period 1980–2005, based on provincial statistical data from yearbooks regarding vehicles and roads, and on the emission factors for each vehicle category in each province calculated by COPERT III program. Results showed that the emissions of CH₄, CO, CO₂, NMVOC, NO_x, PM₁₀, and SO₂ increased from 5, 1066, 19 893, 169, 174, 26, and 16 thousand tons in 1980 to 377, 36 197, 674 629, 5911, 4539, 983, and 484 thousand tons in 2005 at an annual average rate of 19%, 15%, 15%, 15%, 14%, 16%, and 15%, respectively. Statistical analysis of vehicular emissions and GDP showed that they were well positively correlated, which revealed that increase of pollutant emissions has been accompanying the growth of GDP. Spatial distribution of pollutant emissions was rather unbalanced: over three-quarters of the total emissions concentrated in developed regions of China's southeastern, northern and central areas covering only 35.2% of China's territory, while the remaining emissions were distributed over the southwestern, northwestern and northeastern regions covering as much as 64.8% of the territory. In 2005, the Beijing–Tianjin–Hebei region, the Yangtze River Delta, and the Pearl River Delta covering only 2.3%, 2.2%, and 1.9%, respectively, of the territory, generated about 10%, 19%, and 12%, respectively, of the total emissions. Since 1990, motorcycles have been the major contributors to the CH₄, CO, NMVOC, and PM₁₀ emissions, due to the large population. Heavy-duty vans were the major contributors to the NO_x and SO₂ emissions because of high emission factors. Passenger cars contributed about one third of the emissions of each pollutant. Contributions of vehicle categories to emissions varied from province to province, due to the diversity of vehicle compositions among provinces.