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Exposure and risk assessment for fine and ultrafine particles in ambient air

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A large number of studies have reported that daily changes in particulate air pollution are associated with a variety of adverse respiratory outcomes, like symptoms, declines in lung function, and mortality. Recently, similar associations have been reported with cardiovascular outcomes, like hospital admissions, and mortality. The exact mechanisms for the health effects of particles are still unknown. The aim of the project was to improve knowledge of human exposures in European cities to particulate matter of different sizes and different chemical composition, and to study effects of fine and ultra-fine particles on respiratory and cardiovascular health In the first phase, three different aerosol spectrometers that measure continuously concentrations and size distributions of fine and ultra-fine particles in the urban atmosphere have been compared to each other and to commonly used particle measurement techniques. The aerosol spectrometers were comparable with an accuracy of 10% to 20% on average. The differences occurred mainly in the coarser fraction, not in the size of ultra-fine particles. In the second phase, the study has assessed the association between daily and hourly variations in particulate air pollution and cardiorespiratory health among a total of 131 subjects aged 40-84 years in three European cities. During winter 1998-1999, subjects visited the study clinics every two weeks (total 1431 visits) and also kept a daily diary on symptoms. Both PM2.5 and ultra-fine particles were associated with some symptoms, and measures of heart rate variability. Increased risk of ST segment depressions was observed in the only study centre, where there were enough cases. In the same centre, concentration of CC16, a biomarker of lung damage, was associated with PM2.5. Not all of the results were consistent between the three study centres. Especially, associations between lung function, blood pressure and heart rate, and particulate air pollution, were inconsistent. The results can be used to develop standards for air quality, for better and more efficient monitoring of air quality, and as a basis for designing control strategies to improve the air quality and reduce the health effects associated with exposure to particulate matter in ambient air. Remarks: Detailed procedures to investigate the association between short-term variations in air pollution and cardiovascular health have been made freely available at the project web site ( The web site also contains extensive documentation on the project and descriptive statistics of the data collected. Contact: