Assessment of the effects of sugar cane plantation burning on daily countsof inhalation therapy

This study was designed to evaluate the association between sugar cane plan tation burning and hospital visits in Araraquara in the state of Sao Paulo, Brazil. From June 1 to August 31, 1995, the daily number of visits of pati ents who needed inhalation therapy in one of the main hospitals of the city was recorded and used as health impairment estimation. Sedimentation of pa rticle mass (the amount of particles deposited on four containers filled wi th water) was measured daily. The association between the weight of the sed iment and the number of visits was evaluated by means of Poisson regression models controlled for seasonality, temperature, day of the week, and rain. We found a significant and dose-dependent relationship between the number of visits and the amount of sediment. The relative risk of visit associated with an increase of 10 mg in the sediment weight was 1.09 (1-1.19), and th e relative risk of an inhalation therapy was 1.20 (1.03-1.39) on the most p olluted days (fourth quartile of sediment mass). These results indicate tha t sugar cane burning may cause deleterious health effects in the exposed po pulation.