Assessing the impact of regional and local air pollution in East Asia using dispersion modelling

Air pollution is a major problem across the world with more than 90% of the world’s population living in places exceeding the air quality guidelines specified by the World Health Organisation. Transport of air pollution plays a key role in determining the relative influence of local emissions and regional contributions to observed air pollution.

This thesis has investigated the effects of air pollution in Beijing and two islands in South Korea from regional and local sources to understand the impacts of regional meteorology on the transport of pollution in East Asia, through a series of novel and upgraded approaches. Furthermore, a set of policy suggestions were derived to help improve the air quality in the region.

The dispersion model Numerical Atmospheric-dispersion Environment (NAME), was used to evaluate the history of the air mass pathways arriving at the receptor sites. The distribution of air masses over specific regions before arriving at the sites was calculated through an upgraded technique that can be adapted anywhere in the world.

By combining the NAME backward footprints with emission inventories it was possible to calculate the CO concentrations at the sites. In Beijing, it was determined that the contributions from sources located outside of Beijing have a major impact on the CO levels in the city accounting for approximately 46% of the CO in Beijing over five years. Additionally, it was revealed that the CO emitted in China contributed 50 – 59% of the CO air pollution at two South Korean islands. A novel analysis and maping technique was developed in QGIS, to calculate the air pollution contributions at a site on a grid cell by grid cell basis.

Last but not least, the effects of chemistry on the VOC concentrations in Beijing were investigated by combining the NAME footprints, emission inventories and a chemical box model (AtChem2), to reveal the changes in the VOCs during different air pollution scenarios.