Health risk of city populations from exposure to air pollution during summer episodes and the effect of traffic limiting measures
Rombout PJA , Eerens HC , Leeuw FAAM de
RIVM Report 678902001
Ozone is considered to be the most important compound for the development of health effects caused by exposure of the population in urban areas to summer-smog. Exposure to O3 containing outside air during a worst-case episode may cause respiratory and non-respiratory symptoms and lung function decrements, together with a pulmonary inflammatory reaction, an increased airway reactivity and an altered lung clearance. Large variations of the O3 dose within the population and of the individual sensitivity exist, resulting in large differences in the degree of response and in the number of responders. Results from inhalation studies with animals indicate the need to prevent repeated exposures of the population to effect levels of O3. Based on present knowledge it is assumed that repeated exposure to 8 hour mean O3 concentrations of 100-120 mug/m3 will not cause adverse health effects. In case of a total ban on traffic in the larger cities and an unchanged activity pattern of the population a decrease of health risk of maximally 15-20% is to be expected. To prevent unwanted effects on health risk, it could be considered to attend traffic limiting measures by advice to the public to minimize their inhaled O3 dose by restricting their physical activity outdoors, especially between 12.00 and 20.00 hours.