PT  - JOURNAL ARTICLE
AU  - SC Taggart
AU  - A Custovic
AU  - HC Francis
AU  - EB Faragher
AU  - CJ Yates
AU  - BG Higgins
AU  - A Woodcock
TI  - Asthmatic bronchial hyperresponsiveness varies with ambient levels of summertime air pollution
AID  - 10.1183/09031936.96.09061146
DP  - 1996 Jun 01
TA  - European Respiratory Journal
PG  - 1146--1154
VI  - 9
IP  - 6
4099  - http://erj.ersjournals.com/content/9/6/1146.short
4100  - http://erj.ersjournals.com/content/9/6/1146.full
SO  - Eur Respir J1996 Jun 01; 9
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.