The relationship between low-level air pollution exposure and short-term changes in lung function in Dutch children

Following air pollution episodes in the winters of 1985 and 1987, a series of studies was initiated to investigate short-term changes in health status in children in relationship to short-term changes in air pollution concentrations. Air pollution exposure was characterized by measurements of SO2, NO2, PM10, nitrate, sulfate, H+, and HONO. Panels of unselected children were studied in four winters (1987-1991). Lung function was measured repeatedly with spirometry in these children. In the winter of 1990/1991, a panel of children with chronic respiratory symptoms was studied as well, with repeated observations of Peak Expiratory Flow made at the home. The three winters of 87/88, 88/89 and 89/90 were very mild; no air pollution episodes with long range transport from the east occurred. In these three winters, lung function was measured on 86 different days. Altogether, over 800 children participated. H+ concentrations (expressed as H2SO4) were generally below 0.6 microgram/m3, with a maximum of only 3 micrograms/m3. Daily mean SO2 concentrations never exceded 100 micrograms/m3 in this period. Nevertheless, lung function in these unselected children was found to decrease with increasing levels of especially particulate matter air pollution. In the winter of 1990/1991, a minor air pollution episode occurred. Maximum SO2 and PM10 concentrations were 105 micrograms/m3 and 174 micrograms/m3 respectively. This episode was associated with decreased lung function in a group of about 112 unselected children. There was also a relationship with decreased daily PEF readings in a panel of 73 children with chronic respiratory symptoms.