A 5-year follow-up of airway symptoms after nitrogen dioxide exposure in an indoor ice arena.

The authors investigated whether exposure to high levels of nitrogen dioxide (NO2) in an indoor ice hockey arena might be associated with airway symptoms 5 yr later. A follow-up questionnaire was answered by 71 subjects who had experienced such an exposure, accompanied by acute respiratory illness, in Stockholm in 1994. The same questionnaire was answered by 40 reference subjects. The overall response rate for both groups was 71%. Information was obtained regarding various background factors, such as smoking and respiratory symptoms since 1994. For those who had stopped playing ice hockey during the follow-up period, the exposure to high NO2 levels appeared to be associated with an increase in upper airways symptoms (i.e., nasal blockage or rhinitis) (odds ratio = 3.1, 95% confidence interval = 1.1, 8.8), after adjustment for age, smoking, and family history of allergy. These data suggest that exposure to high NO2 levels in an indoor ice arena may be associated with increased airway symptoms several years later.