This work investigates transboundary air pollution in Asia through atmospheric modeling and policy analysis. As an example of models shaping environmental policy and as the only multi-lateral air pollution agreement to date, the Convention on Long-Range Transboundary Air Pollution in Europe (LRTAP) is selected as a case study. Results from the RAINS integrated assessment model were used to calculate nationally differentiated emission ceiling in later LRTAP protocols. Atmospheric chemistry and transport are included in RAINS through the use of transfer coefficients relating pollutant emissions and deposition within Europe. These were calculated by a Lagrangian chemical transport model (the EMEP model). Characteristics of the EMEP model contributing to its policy acceptance are discussed and compared to a similarly-structured model for Asia, ATMOS, the modeling tool developed for this study.

Following past work with ATMOS to simulate sulfur species in Asia, here ATMOS is developed to include odd-nitrogen (NOx, HNO3, and PAN). Fitting with the linear structure of ATMOS and the emphasis on computational efficiency, a simplified chemical scheme for use in the NOAA Geophysical Fluid Dynamics Laboratory Global Chemical Transport Model (GFDL GCTM) is adopted.

Model results are compared against measurements and against simulations from the GFDL GCTM. The suitability of ATMOS to policy issues is discussed and critiqued, and model-calculated source-receptor relationships for Asia are reported. Significant exchange of NOy occurs among China, North and South Korea, and Japan.

On an annual average, the model estimates that long-range transport contributes a significant percentage of total nitrate deposition throughout east Asia. China, the largest emitter of the region, contributes 18% to nitrate deposition in Taiwan, 18% in Japan, 46% in North Korea, and 26% in South Korea. South Korea contributes 12% to nitrate deposition in Japan, due to its close upwind proximity. Compared with total acid deposition (nitrate + sulfate), nitrate contributes 30-50% over northern Japan, 30-60% in India, and 50-90% in southeast Asia where biomass burning emits high levels of NOx. The percentage contribution of nitrate is very low in China, where emissions and deposition of sulfur are extraordinarily high.