Climate change impacts on O3, NOx, OH and HO2 in Malaysia

The Earth's atmosphere is an oxidizing blanket with ozone and hydroxyl radical as the principal oxidants which could be affected by climate change where climate change may change the chemical composition of the species. How much the climate change affects these oxidants in the tropical region especially in Malaysia is relatively unknown. This study was explore in order to enhance the understanding of this issue by achieving the objectives: (a) to simulate climate changes using regional climate modeling system PRECIS (Providing Regional Climates for Impacts Studies) under SRES (Special Report on Emissions Scenarios) B2 and A2 emission scenarios of the Intergovernmental Panel on Climate Change (IPCC) for the Malaysian domain; (b) to investigate the impact of climate change to the air quality and atmospheric oxidizing capacity under both emission scenarios using chemistry model CiTTyCAT (Cambridge Tropospheric Trajectory model of Chemistry and Transport). In both scenariOS, surface temperatures in the future were found to increases during the both seasons in Malaysia, wet season (December, January, February) and dry season (June, July, August) by 2 DC and 3 DC respectively. For precipitation rate under B2 scenario, it decreases by -0.56 mm day-l during wet season but increases by 0.34 mm day-l during dry season. Meanwhile under A2 scenario the precipitation rate increases during the both seasons. In response to the climate change, 0 3 concentration in remote (Danum) and rural (Kapit) area showed a high decrease in percentage of about 20 to 50 % but relatively lower in sub urban (Sg. Petani) area with only 2 to 5 % and showed variability changes in urban areas (Kota Kinabalu, Kuala Lumpur and Pasir Gudang). Under the same climate scenariOS, the oxidizing capacity in term of OH concentrations was decreased in remote and rural areas about 20 to 50 % of changes. Meanwhile the increases in sub urban area of about 2 to 15 % changes were observed. High variability of changes was observed in the urban areas. In the next century, changes of the climate in Malaysia will affect the air quality and oxidizing capacity of the atmosphere. Thus, it is important to assess the extent of vulnerability and risk of climate to the air quality in the region to improve the mitigative and adaptive capacity policy and strategy