Abnormal Cold Periods and Pollution Build -Up

Urban NO2 and NO pollution in relation to the North Atlantic Oscillation NAO (Abstract, M. Grundström, H.W. Linderholm, J. Klingberg and H. Pleijel, Atmospheric Environment, February 2011)

Also discussed here: Cold Winters Mean More Pollution, Swedish Study Suggests (Science Daily, Feb. 22, 2011)

Just as El Nino and La Nina have 6-10 year cycles and result in widespread global anomalies such as thaws, floods and droughts, the somewhat and more scientifically based North Atlantic Oscillation (NAO) is associated with cold outbreaks in Europe and elsewhere. The article under review today goes further by examining the link between cold periods and the emission of nitrogen oxides (main source is vehicle exhaust) and the implications for poorer air quality as a result. Such build-ups of pollutants also would impact human health as many earlier posts on this web site attest. Careful monitoring of the NAO could be a key to assessing the health impacts in urban centres subjected to cold periods.



Key Quotes:

“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.”

“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"

"These extremely cold winters in Gothenburg, with high cold air, bring a clear deterioration in air quality,"

"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."

“The researchers refer, for example, to the fact that the number of exceedances of the hourly limit for nitrogen dioxide (90 µg/m3) increased. This can be linked to the fact that the NAO has tended increasingly to be in a negative phase during the winter months over the last two years”

Related articles

• Cold winters mean more pollution (eurekalert.org)
• Cold winters mean more pollution (physorg.com)
• Beijing celebrates Chinese new year with blue skies ahead - and above (guardian.co.uk)
• Study might help predict inversions ()
• Why is it unusually cold in the north? (lookatvietnam.com)
• La Nina Bringing Warm Winter to Southeast (planetsave.com)
• Climate Change Could Be Worsening Effects of El Niño, La Niña (stephenleahy.net)
• Defining La Nina and What it Does to Climate (brighthub.com)
• La Nina helping direct winter storm to Midwest (seattletimes.nwsource.com)