Intercontinental Air Pollution Transport: A Southern Hemisphere Perspective

Intercontinental air pollution transport has received little attention in the Southern Hemisphere in comparison to the Northern Hemisphere. As air quality becomes an increasingly important environmental and health problem for countries in the Southern Hemisphere to control and improve, it is vital to be able to quantify the impact a given region’s anthropogenic air pollution emissions will have on other regions downwind. In this thesis, the Hemispheric Task Force on Air Pollution (HTAP2) Protocol was used to quantify the impact of intercontinental air pollution transport for Southern Hemisphere ozone (O3) and particulate matter (PM2.5) (and their key precursors) in Australia, South America, South East Asia and Sub-Saharan Africa. A 2008 scenario, a 2030 RCP4.5 scenario and an alternate African renewable energy emission scenario (chosen given the region’s rapid anthropogenic growth) were simulated to quantify this impact. It was found that in 2008 foreign sources were responsible for: 53% of Australian O3 concentrations, 26% of South American O3, 57% of South East Asian O3 and 48% of Sub-Saharan African O3 concentrations. Similarly, for PM2.5 it was found that in 2008 foreign sources were responsible for: 20% of Australian PM2.5 concentrations, 18% of South American PM2.5 concentrations, 61% South East Asian PM2.5 concentrations, and 31% of Sub-Saharan African PM2.5 concentrations. It was shown that in 2030, the ratio of foreign to local sources impacting O3 and PM2.5 concentrations will change for all four regions. Australia will experience the largest change out of the four regions, with relative foreign source contributions to O3 concentrations increasing to 73% (+20% from 2008) and relative foreign sources contributions to PM2.5 concentrations increasing to 31% (a +11% from 2008). An alternate 2030 emissions scenario in which African growth is partly fuelled by renewable energy showed impacts both within the Sub-Saharan African region and outside the region, in Australia. Most notably, in this scenario the sources impacting Australian PM2.5 concentrations became more local, with a 2% decrease in the relative ratio of foreign to local sources. This research shows the significant impact of intercontinental air pollution transport across the Southern Hemisphere, both now and in the future. As Southern Hemisphere countries seek to improve their air quality, they must consider not only their own local sources of air pollutants but also those from distant continents, highlighting the need for global cooperation in the area of air quality.