Asthmatic responses to airborne acid aerosols.
BACKGROUND
Controlled exposure studies suggest that asthmatics may be more sensitive to the respiratory effects of acidic aerosols than individuals without asthma. This study investigates whether acidic aerosols and other air pollutants are associated with respiratory symptoms in free-living asthmatics.


METHODS
Daily concentrations of hydrogen ion (H+), nitric acid, fine particulates, sulfates and nitrates were obtained during an intensive air monitoring effort in Denver, Colorado, in the winter of 1987-88. A panel of 207 asthmatics recorded respiratory symptoms, frequency of medication use, and related information in daily diaries. We used a multiple regression time-series model to analyze which air pollutants, if any, were associated with health outcomes reported by study participants.


RESULTS
Airborne H+ was found to be significantly associated with several indicators of asthma status, including moderate or severe cough and shortness of breath. Cough was also associated with fine particulates, and shortness of breath with sulfates. Incorporating the participants' time spent outside and exercise intensity into the daily measure of exposure strengthened the association between these pollutants and asthmatic symptoms. Nitric acid and nitrates were not significantly associated with any respiratory symptom analyzed.


CONCLUSIONS
In this population of asthmatics, several outdoor air pollutants, particularly airborne acidity, were associated with daily respiratory symptoms.
Ostro
B D
BD
California Department of Health Services, Berkeley 94704.
Lipsett
M J
MJ
Wiener
M B
MB
Selner
J C
JC
D000328:Adult; D000393:Air Pollutants / Q000009:adverse effects* / Q000032:analysis; D001249:Asthma / Q000139:chemically induced / Q000453:epidemiology* / Q000503:physiopathology; D003120:Colorado / Q000453:epidemiology; D004784:Environmental Monitoring; D062665:Epidemiological Monitoring; D005260:Female; D006801:Humans; D006863:Hydrogen-Ion Concentration; D016018:Least-Squares Analysis; D008297:Male; D009566:Nitrates / Q000009:adverse effects / Q000737:chemistry; D017942:Nitric Acid; D013431:Sulfates / Q000009:adverse effects / Q000737:chemistry; D011795:Surveys and Questionnaires
D000393:Air Pollutants; D009566:Nitrates; D013431:Sulfates; D017942:Nitric Acid