Tuesday, February 22, 2011

Cold winters mean more pollution

University of Gothenburg (Sweden): Differences in air pressure over the North Atlantic have meant that the last two winters in Gothenburg have been extremely cold. This has led to the air in Gothenburg being more polluted with nitrogen oxides than ever before. A new study from the University of Gothenburg shows that there is a strong link between climate and air pollution.

The winter weather in Gothenburg and large parts of North-West Europe is partly down to the North Atlantic Oscillation (NAO), in other words the differences in air pressure over the North Atlantic. The NAO swings between positive and negative phases depending on the differences in air pressure between Iceland and the Azores. When the NAO is in a negative phase – as has been the case during the last two winters – the city has cold winters because the low pressure sits over southern Europe, while cold air from the polar region or Siberia sits over northern Europe.

In a study carried out in Gothenburg, a group of researchers from the University of Gothenburg investigated how the concentrations of nitrogen oxides (NO and NO2) in the air can be linked to the weather. Published in the scientific journal Atmospheric Environment, the study shows that the air quality standard has been exceeded more and more frequently during periods of a negative NAO even though emissions have fallen in the city centre since 2000 according to official measurements from the Environmental Administration.

“These extremely cold winters in Gothenburg, with high cold air, bring a clear deterioration in air quality,” says Maria Grundstr√∂m from the University of Gothenburg’s Department of Plant and Environmental Sciences, one of the researchers behind the study. “With typical Gothenburg weather – low air pressure with precipitation and strong winds – the air pollution is dispersed more quickly on account of better air mixing.”…

Gothenburg in warmer weather, shot by Wigulf, Wikimedia Commons, under the Creative Commons Attribution-Share Alike 2.5 Generic license

No comments: