Press release 2017-04-25

Wood burning and traffic greatest threats to air in cities

Health effect measurements from Stockholm, Gothenburg and Umeå shows that the importance of local air pollution emissions from wood burning and road traffic is greater than earlier national level estimates have shown. What most surprised the researchers was the impact from wood burning, with effects in the form of mortality in the same magnitude as that from traffic. The study also shows a clear link between exposure to soot and the risk of stroke.

The new findings regarding traffic and wood burning was presented by SCAC, the Swedish Clean Air and Climate Research Programme, during a conference earlier this year.

– The results show that it is extremely important to continue working to find ways to reduce local emissions of small particles from traffic and wood burning in Swedish cities, says Peringe Grennfelt at IVL Swedish Environmental Research Institute and the research programme coordinator.

Although the air in Sweden has gradually improved, in recent years concentrations of air pollutants have not decreased at anything like the rate deemed necessary. Emissions from traffic and wood burning stoves are still the two major outstanding issues in Swedish towns.

Scientists estimate that local emissions of small particles from traffic and wood burning causes 170-400 deaths each year in Stockholm. The corresponding figures for Gothenburg and Umeå are 100-240 and 9-23.

– Although long-distance air masses make the largest contribution to particulate concentrations in Swedish cities, our understanding of the effects of various particles indicates that it is the local emissions of small particles from traffic and wood burning that have the greatest impact on mortality, says Bertil Forsberg at Umeå University.

Small particle emissions emanating from the burning of wood are equal to or slightly greater than those from road traffic. As far as soot is concerned, where diesel vehicles are a major source, road traffic emits more than wood fires.

Under SCAC, research groups from IVL, Karolinska Institutet, Umeå University and the University of Gothenburg have studied how air pollution affects cardiovascular and pulmonary functions and pregnancy outcomes. The findings show that there is a clear link between exposure to soot and stroke, as well as between exhaust particles and low birth weight.

– There is also a link between exposure to air pollution and reduced lung function, says Göran Pershagen from Karolinska Institutet.

Under the SCAC programme research has been carried out by some of Sweden's leading research groups in the field, and targets both the effects on health, ecosystems and climate action as a basis for limiting emissions of air pollutants.

For more information, please contact:

Peringe Grennfelt, peringe.grennfelt@ivl.se tel. 010-788 67 84
Bertil Forsberg, bertil.forsberg@umu.se, tel. 090-785 27 51
Göran Pershagen, goran.pershagen@ki.se, tel. 08-524 874 60

SCAC – the Swedish Clean Air and Climate Research Programme, is a three-year research programme funded by the Swedish Environmental Protection Agency. Participating Bodies: IVL Swedish Environmental Research Institute (coordinator), University of Gothenburg, Stockholm University, Lund University, Karolinska Institutet, Umeå University, Stockholm city with SLB Analysis, SMHI and IIASA.