Table 2 Description of air pollution indicator variables and time spent in all lifetime residences
Proximity to industriesWindows facing traffic streetNumber of lanesIntensity of trucks and busesSize of city
Low exposureNo industriesNo windows facing traffic streetNo windows facing traffic streetNo windows facing traffic street>25 years living in a small village/town (<20 000 inhabitants)
High exposure>25 years>30 years⩾25 years with more than 2 lanes on both sides of the street⩾25 years with high intensity traffic>40 years living in a city (>100 000 inhabitants)

  • Subjects who did not fit in either of the two extreme categories were considered as intermediate exposed. Questions about the type and quantity of traffic (number of lanes and intensity of traffic on residence facing the traffic street) were asked of subjects who had windows facing a traffic street.