RESPIRATORY SYMPTOMS IN A SUSCEPTIBLE POPULATION DUE TO BURNING OF AGRICULTURAL RESIDUE

Study objectives: To identify characteristics associated with respirat ory symptoms due to an episode of air pollution. Design: Mail survey. Setting: In October 1992, the population of the city of Winnipeg was e xposed to elevated levels of particulate matter (total and <10 mu m si ze), carbon monoxide, nitrogen dioxide, and volatile organic compounds due to smoke from adjacent fields where farmers were burning agricult ural residue (straw and stubble). Participants: We surveyed 428 partic ipants in the ongoing Lung Health Study (35 to 64 years old, both sexe s) with mild to moderate airways obstruction (mean FEV, percent predic ted 73+/-12%), and a high level of airways hyperreactivity (23% of men and 37% of women). Results: While 37% of subjects were not bothered b y smoke at all, 42% reported that symptoms (cough, wheezing, chest tig htness, shortness of breath) developed or became worse due to the air pollution episode and 20% reported that they had breathing trouble, Th ose with symptoms were more likely to be female than male and were mor e likely to be ex-smokers than smokers. Subjects with asthma and chron ic bronchitis were also more likely affected, The degree of airways ob struction and the level of bronchial hyperresponsiveness were not asso ciated with increased susceptibility. Conclusions: Gender, smoking hab it, and respiratory symptoms but not bronchial hyperresponsiveness or the degree of airways obstruction are factors influencing susceptibili ty to symptoms due to air pollution in adult smokers and former smoker s.