Traffic-related air pollution - the health effects scrutinized

Numerous studies have been published on the health effects associated with exposure to air pollution. Air pollution is acknowledged as a public health risk and air quality regulations are set for specific air pollutants to protect human health. A major pollutant, well known for its adverse health impact, is particulate matter (PM) of which road traffic is a major source. Therefore, the health effects of traffic-related air pollution have been under considerable scrutiny. We examined in vivo the role of road traffic emissions exerting biological responses and toxicity of PM. PM collected at high traffic locations was more potent in enhancing inflammation in the lung than PM from low traffic density areas, which underlined the importance of considering road traffic as a source of harmful air pollutants. Furthermore, the results of our studies suggest that PM from other sources like wood combustion and wear emissions (e.g. from brake and tyre wear) could be of relevance based on the associations with specific elements like potassium, copper, barium and zinc. To what extent emission of various sources of air pollution contribute to the health effects is still surrounded by uncertainty. PM mass seems not the best metric to predict air-pollution-related health effects and our research has emphasized the importance of particle size and composition as determinants of the health risks imposed by air pollution. The results of the in vivo studies in which we examined the acute detrimental effects of PM from different locations showed that coarse particles (2.5-10 µm) exert significant adverse toxicity, which stresses the importance of coarse particles as a health relevant fraction of PM, in addition to fine