Anthropogenic NOx emissions in Asia in the period 1990–2020

Nitrogen oxides emissions in Asia during the period 1990–2020 due to anthropogenic activity are presented. These estimates are based on the RAINS-ASIA methodology (Foell et al., 1995, Acid Rain and Emission Reduction in Asia, World Bank), which includes a dynamic model for energy forecasts, and information on 6 energy sectors and 9 fuel types. The energy forecasts are combined with process emission factors to yield NOx emission estimates at the country level, the regional level, and on a 1 degree by 1 degree grid. In 1990 the total NOx emissions are estimated to be 19 Tg NO2, with China (43%), India (18%) and Japan (13%) accounting for 75% of the total. Emissions by fuel are dominated by burning of hard coal and emissions by economic activity are dominated by the power, transport, and industrial sectors. These new estimates of NOx emissions are compared with those published by Hameed and Dignon (1988, Atmospheric Environment 22, 441–449) and Akimoto and Narita (1994, Atmospheric Environment 28, 213–225). Future emissions under a no-further-control scenario are also presented. During the period 1990–2020 the NOx emissions increase by 350%, to 86 Tg NO2. The increase in NOx emissions by sector and end-use varies between countries, but in all countries this increase is strongest in the power and transport sectors. These results highlight the dynamic nature of energy use in Asia, and the need to take the rapid growth in NOx emissions in Asia into account in studies of air pollution and atmospheric chemistry.