/ 14 June 2010

Global warming will worsen air pollution

Research by a PhD student at the University of KwaZulu-Natal suggests that municipal governments will have to reassess air pollution monitoring priorities as climate change kicks in.

Tirusha Thambiran, an environmental sciences doctoral student, reviewed the scientific links between air pollution and climate change. She found that convection, which removes pollutants from lower to higher layers of the atmosphere, is likely to intensify under climate change, with ‘potentially large consequences”.

Moreover, ‘in a warmer climate there will be warmer winds, which in turn will lead to higher pollutant concentrations”, she said in a report in the most recent edition of the South African Journal of Science.

In addition, ‘it is anticipated that a warmer climate will be conducive to increased lightning, which could have a large effect on ozone”.

Climate change will alter the temperature and moisture levels of the soil, affecting the creation of nitrogen oxide gases, she wrote, noting that soil contributes close to half (40%) of nitrogen gas emissions in Africa.

The large-scale burning of fossil fuels — such as coal and oil — has released high levels of nitrogen oxides into the atmosphere, where it behaves in harmful but different ways at different levels.

When nitrogen oxide reaches the stratosphere, between 10km and 50km above the planet’s surface, it destroys the protective ozone layer, resulting in higher levels of ultraviolet radiation, which increases the risk of people developing skin cancer and cataracts.

Closer to the Earth’s surface, nitrogen oxide gases make ozone, which can become smog on a calm day and has been linked to breathing problems, lung damage, increased risks of cancer and weaker immune systems.

At ground level, surface nitrogen oxides dissolve in airborne water to make acid rain, which corrodes stone and metal and damages buildings.