Air pollution and emergency room admissions for chronic obstructive pulmonary disease: a 5-year study.

An association between sulfur dioxide levels in urban air and the daily number of emergency room admissions for chronic obstructive pulmonary disease was previously reported in Barcelona, Spain, for the period 1985-1986. The present study assesses this association over a longer period of time, 1985-1989. This made it possible to carry out separate analyses for the winter and summer seasons and thus to control more adequately for weather and influenza epidemics. An increase of 25 micrograms/m3 in sulfur dioxide (24-hour average) produced adjusted changes of 6% and 9% in emergency room admissions for chronic obstructive pulmonary disease during winter and summer, respectively. For black smoke, a similar change was found during winter, although the change was smaller in summer. The association of each pollutant with chronic obstructive pulmonary disease admissions remained significant after control for the other pollutant. The present findings support the conclusion that current levels of sulfur dioxide and black smoke may have an effect on the respiratory health of susceptible persons.