Air pollution and health – Indicators, trends and impacts

Abstract: This thesis focuses on some of the limitations and difficulties that exist when it comes to quantifying the human health effects that arise as a result of air pollution exposure. The following four issues are particularly analysed and discussed: 1) The measurement techniques used for carbonaceous particles and their lack of consistency; 2) Do the health risks associated with exposure to PM10 depend on the content of elemental carbon in the aerosol?; 3) Trends in air pollutants and the health effects that arise as a result of changed exposure to the measured pollutants; 4) The associations between the measured concentrations of different air pollutants in Stockholm and the daily number deaths; 5) Air quality indicators and health outcomes as basis for an air quality health index (AQHI).The method that has been used is largely based on empirical data analysis, where further statistical processing has been used in order to clarify the scientific issues. The overall conclusions are the following: 1) The health impact assessments associated with exposure to carbonaceous particles would benefit from the introduction of a more uniform measurement technique in order to get more consistent and reliable results; 2) The health risks associated with exposure to PM10 are dependent on the content of elemental carbon; 3) The life expectancy increase associated with decreasing NOx trends during 1990–2015 in Stockholm, Gothenburg and Malmo make up as much as about 20 % of the total gain in life expectancy during this period, which clearly shows the beneficial effects related to decreased exposure; 4) The associations between daily mortality and the concentrations of O3 and PM2.5-10 in Stockholm are statistically significant, which does not apply to the exhaust-related pollutants, possibly reflecting behavioural factors affecting the degree of exposure; 5) In comparison with the currently used air quality index (AQI), the air quality health index (AQHI) is a more useful tool in order to address the short-term health effects associated with multi-pollutant exposure to NOx, O3, PM10 and birch pollen.We hope that these findings will be useful from a policy point of view. Introducing a more consistent measurement technique for soot particles would be beneficial in assessing the health effects related to exposure to these particles. The increase in life expectancy associated with decreasing NOx trends shows the benefits from a public health perspective when it comes to introducing emission-reducing measures from traffic. The AQHI would be beneficial to implement in legislation, as it is based on several pollutants, which means that the cumulative health effects associated exposure to several different air pollutants are accounted for.