Individual traffic-related air pollution and new onset adult asthma: A GIX-based pilot study

The objective of this pilot study is to investigate the relation between asthma and wheeze debut and individually estimated exposure to traffic-related air pollutants with a validated exposure system (AirGIS). A non-smoking cohort with recently acquired asthma or wheeze as well as matched controls was identified from a large cross-sectional study. All residential and working addresses with corresponding time periods for a 10 year period were successfully identified for all study participants (N=33) and exposure estimated for both urban background and street level. Individual levels of air pollutants in the years preceding debut of asthma or wheeze were analyzed using survival analysis. No significant correlations between exposure levels and onset of disease or symptom were demonstrated. A tendency towards higher levels of nitrogen oxides exposure during the year prior to debut was seen in wheeze cases. Substantial problems in determining time of onset were encountered. It is recommended that the analytic methods developed in this pilot study are used in a larger prospective cohort to investigate individual trafficrelated air pollutants as a risk factor for the development of new asthma and wheeze.