Quantification of population exposure to NO2, PM2.5 and PM10 and estimated health impacts in Sweden 2010

• Sweden is one of the countries in Europe which experiences the lowest concentrations of air pollutants in urban areas. Despite this, health impacts of exposure to ambient air pollution is still an important issue in the country and the concentration levels, especially of nitrogen dioxide (NO2) and particles (PM10 and PM2.5), exceed the air quality standards at street level in many urban areas.IVL Swedish Environmental Research Institute and the Department of Public Health and Clinical Medicine at Umeå University have, on behalf of the Swedish EPA, performed a health impact assessment (HIA) for the year 2010. The population exposure to annual mean concentrations of NO2, PM10 and PM2.5 in ambient air has been quantified and the health and associated economic consequences have been calculated based on these results.Environmental standards as well as environmental objectives are to be met everywhere, also at the most exposed kerb sides. However, for exposure calculations it is more relevant to used urban background data, on which also most available exposure-response functions are based. The results show that in 2010 most of the country had rather low NO2 urban background concentrations in comparison to the environmental quality standard for the annual mean (40 μg/m3) and the population weighted average exposure to NO2 was 6.2 μg/m3. Likewise the PM10 urban background concentrations, compared to the environmental quality standard for the annual mean (40 μg/m3), were also low in most parts of the country. However, in some parts, mainly in southern Sweden the concentration levels were of the same magnitude as the environmental objective (20 μg/m3 as an annual mean) for the year 2010. The majority of people, 90%, were exposed to annual mean concentrations of PM10 less than 20 μg/m3. Less than 5% of the Swedish inhabitants experienced exposure levels of PM10 above 25 μg/m3.The modelling results for PM2.5 show that the urban background concentration levels in 2010 were of the same order of magnitude as the environmental objective (12 μg/m3 as an annual mean for the year 2010) in a quite large part of the country. About 70% of the population was exposed to PM2.5 annual mean concentrations lower than 10 μg/m3, while less than 15% experienced levels above 12 μg/m3.There is currently within the research community a focus on the different types of particles and more and more indications that their impact on health and mortality differ. Yet a common view is still that current knowledge does not allow precise quantification of the health effects of PM emissions from different sources. However, when the impact on mortality from PM10 is predicted, exposure-response functions obtained using PM2.5 are usually reduced using the PM2.5/PM10 concentration ratio.Assessment of health impacts of particle pollution is thus difficult. Even if WHO in HRAPIE and others assessments still choose to recommend the same relative risk per particle mass concentration regardless of source and composition, we find this a too conservative approach. Therefore we applied different exposure-response functions for primary combustion generated particles (from motor vehicles and residential wood burning), for road dust and for other particles (the regional background of mainly secondary particles).For primary combustion particles we have in this study applied the exposure-response coefficient 17 % per 10 μg/m3 for mortality. For other PM2.5 sources and for PM2.5 totally, we applied the 6.2 % per 10 μg/m3 as was recently recommended by WHO. For road dust we here assumed only a "short-term" effect on mortality as has been done for PM10 in general.We estimated approximately 3 500 preterm deaths per year from PM2.5 without any division between sources and using the exposure-response coefficient 6.2 % per 10 μg/m3. Assuming a division between sources we estimated that non-local sources caused just over 3 000 preterm deaths per year (exposure-response coefficient 6.2 % per 10 μg/m3), and residential wood burning caused just over 1 000 preterm deaths per year (exposure-response coefficient 17 % per 10 μg/m3). In addition, we estimated approximately 1 300 preterm deaths per year from locally generated vehicle exhaust using NO2 as an indicator (exposure-response coefficient 17 % per 10 μg/m3 and a 5 μg/m3 cut-off). Preterm mortality related to short-term exposure to road dust PM, estimated to over 200 deaths per year (exposure-response coefficient 17 % per 10 μg/m3), should probably be added to the impact of local traffic in Sweden. In summary, the total number of preterm deaths can be estimated to approximately 5 500 per year when taking into account differences in exposure-response for different PM sources. Note that the ground-level ozone has not been taken into account in this study, but can still cause premature deaths and other health issues.For morbidity we have in this study included only some of the potentially available health endpoints to be selected. Only a few important and commonly used endpoints were included to allow comparisons with other health impact assessments and health cost studies.The estimated respiratory and cardiovascular hospital admissions due to the short-term effects of air pollution may seem to be low in comparison with the estimated number of deaths, new chronic bronchitis cases and restricted activity days. However, for hospital admissions we can only estimate the short-term effect (acute effect) on admissions, not the whole effect on hospital admissions following morbidity induced by the air pollution exposure.The socio-economic costs (welfare losses) related to population exposure to air pollutants as indicated by NO2 were calculated both with and without a threshold of 5 μg/m3. The results suggest that the health effects related to annual mean levels of NO2 can be valued to between 7 and 25 billion Swedish crowns (SEK2010) during 2010 depending on if a threshold of above 5 μg/m3 is included or not.Moreover, welfare losses resulting from exposure to PM pollutants from road dust, domestic heating and other sources can be valued to annual socio-economic costs of about 35 billion SEK 2010 during 2010. Approximately 6.5 of these 35 billion SEK2010 are from productivity losses in society. Furthermore, the amount of working and studying days lost constitutes about 0.3% of the total amount of working and studying days in Sweden during 2010. Using the division between PM sources and NO2 (with a 5 μg/m3 cut-off) as an indicator of traffic combustion the total socio-economic cost would be approximately 42 billion SEK2010.In a counterfactual analysis, impacts of a hypothetical large scale introduction of electric passenger vehicles in the Stockholm, Göteborg, and Malmö regions were studied. The results from this analysis indicated that the health benefits from introducing ~10% electric vehicles in these regions would motivate 13 – 18% of the investment.

• Befolkningens exponeringen både för partiklar (PM) och kvävedioxid (NO2) har minskat mellan 2005, då den föregående beräkningen genomfördes, och 2010. Knappt 10 % av Sveriges befolkning utsätts för bakgrundshalter av PM10 (partiklar mindre än 10 μm) högre än 20 μg/m3 i den allmänna utomhusluften. Denna halt motsvarar miljömålet för år 2010, men nivån skall även klaras i mer belastade områden såsom gaturum. För mindre partiklar (PM2,5, partiklar mindre än 2,5 μm) visar motsvarande jämförelse med miljömålet (12 μg/m3 för år 2010) på att knappt 15 % av landets invånare exponeras för halter över denna nivå.Om man utgår från att PM2.5 har samma farlighet oavsett ursprung så uppskattar vi att cirka 3 500 förtida dödsfall årligen inträffar i Sverige på grund av den totala exponeringen. Troligtvis är det inte tillräckligt att göra beräkningar utifrån den totala halten, eftersom partiklar av olika ursprung tycks ha olika farlighet. Med separata bedömningar för olika källor till PM uppskattar vi att det årligen rör sig om cirka 3 000 förtida dödsfall från partiklar som inte genererats lokalt. Förbränningspartiklar från vedeldning uppskattas orsaka ytterligare drygt 1 000 förtida dödsfall per år. Utöver dessa dödsfall uppskattar vi, utifrån exponeringen för NO2, att lokalt genererade avgaser leder till ytterligare minst 1 300 förtida dödsfall per år, samt vägdamm till ytterligare drygt 200 dödsfall orsakade av kortvarig exponering. Sammanfattningsvis kan antalet förtida dödsfall uppskattas till cirka 5 500 per år på grund av dessa exponeringar, när beräkningarna tar hänsyn till olika exponering-responsvärden för olika källor.De samhällsekonomiska kostnaderna (välfärdsförluster) relaterade till exponering för luftföroreningar mätt som NO2 beräknades både för effekter över 5 μg/m3 och utan tröskel. Resultaten tyder på att de hälsoeffekterna, relaterade till årsmedelhalten av NO2, kan värderas till mellan 7 och 25 miljarder kronor under 2010, beroende på om en tröskel på över 5 μg μg/m3 ingår eller ej.Resultaten från vår studie visar att negativa hälsoeffekter relaterade till förorenad luft med höga nivåer av PM kan värderas till årliga samhällsekonomiska kostnader (välfärdsförluster) på ca 35 miljarder svenska kronor under 2010. Ungefär 6,5 av dessa 35 miljarder utgörs av produktivitetsförluster i samhället. Detta motsvarar en förlust i antalet arbets- och studiedagar motsvarande drygt 0,3 % av den totala mängden arbets- och studiedagar under 2010.

Ämnesord

NATURVETENSKAP  -- Geovetenskap och miljövetenskap -- Miljövetenskap (hsv//swe)

NATURAL SCIENCES  -- Earth and Related Environmental Sciences -- Environmental Sciences (hsv//eng)

Nyckelord

Nationellt finansierad miljöövervakning

National

Health

Hälsorelaterad miljöövervakning

Clean air

Frisk luft

Luftföroreningar - exponeringsstudier

Luftföroreningar - exponeringsstudier

Publikations- och innehållstyp

vet (ämneskategori)

rap (ämneskategori)