RT Journal Article
SR Electronic
T1 Asthmatic bronchial hyperresponsiveness varies with ambient levels of summertime air pollution
JF European Respiratory Journal
JO Eur Respir J
FD European Respiratory Society
SP 1146
OP 1154
DO 10.1183/09031936.96.09061146
VO 9
IS 6
A1 SC Taggart
A1 A Custovic
A1 HC Francis
A1 EB Faragher
A1 CJ Yates
A1 BG Higgins
A1 A Woodcock
YR 1996
UL http://erj.ersjournals.com/content/9/6/1146.abstract
AB It is widely believed that the mechanisms of action of outdoor air pollutants are the same as those found in the laboratory, although few studies have attempted to clarify this issue. This study investigates the relationship of asthmatic bronchial hyperresponsiveness (BHR), a marker of airway inflammation, and pulmonary function to ambient levels of summertime air pollution. Thirty eight nonsmoking adult asthmatic subjects underwent repeated measurement of methacholine BHR, using Yan's method, at differing levels of air pollution (O3, SO2, NO2, smoke) during summer 1993. A total of 109 evaluable tests were performed: 31 subjects completed three or more challenge tests, and seven managed two. Levels of all pollutants remained within current World Health Organization (WHO) Guidelines for Health. Changes in BHR were found to correlate significantly with changes in the levels of 24 h mean SO2, NO2 and smoke; 48 h mean NO2 and smoke; 24 h lag NO2; although the effect was only small, accounting for approximately 10% of the variability in within-subject BHR between visits. Twenty four hour lag NO2 was also associated with forced vital capacity (FVC). In conclusion, in subjects with asthma, methacholine bronchial hyperresponsiveness varies with ambient levels of summertime air pollution. This suggests that changes in airway inflammation underlie the increased respiratory morbidity known to accompany pollution episodes.