The project has developed a method to estimate current, long-term average exposure to traffic-related air pollution at street address level by combining results from a measurement program with data from Geographic Information Systems (GIS) in the three study areas. This is an important achievement as it allows future epidemiologic studies on air pollution health effects to use much more detailed exposure assessment than was previously possible. The feasibility and validity of these methods was checked by applying them to the address data bases of the three cohort studies to generate address-level concentrations for three traffic-related air pollutants, fine particulate matter (PM2.5), soot (Black Smoke) and nitrogen dioxide (NO2). A high correlation was found in all study areas between the available GIS characteristics (such as population density and proximity to major roads) and the measured concentrations at 40 sites in each of the three countries. The risk assessment part suggested that in some of the areas, traffic-related air pollution was indeed related to respiratory symptoms reported in the first one or two years of life. Further follow-up of the cohort children is needed to more fully address the risks. The newly funded AIRALLERG project (QLRT 2000-00073) will ensure that a more complete picture will emerge in the next few years.
The method that was developed makes use of GIS variables (notably degree of urbanisation based on either population or address density, and proximity to main roads) to estimate exposure of human beings to traffic related air pollution. A local measurement program has been designed and tested to validate the method in specific local situations against actual measurements of the traffic-related air pollution components fine particulate matter (PM2.5), 'soot' (a measure for diesel exhaust) and nitrogen dioxide (NO2).