title: Limited airway effects in mild asthmatics after exposure to air pollution in a road tunnel.
abstract: Ambient air pollution is a contributing factor to respiratory morbidity and mortality and asthmatics are a particularly vulnerable population. The aim of the study was to investigate whether acute exposure to traffic related air pollution in a road tunnel would increase bronchial responsiveness in mild asthmatics, and if this would be accompanied by increased measures of inflammatory markers in the airways assessed by nasal lavage (NAL) and induced sputum. Fourteen mild asthmatics (7 treated with inhaled corticosteroids) were exposed for 2 h in a road tunnel and a control environment, respectively, separated by at least 3 weeks. Symptoms and peak expiratory flow (PEF) were recorded. Seven hours following exposure sessions, subjects underwent measurements of fraction of exhaled nitric oxide (FENO), spirometry, and a bronchial provocation test. NAL, induced sputum and blood samples were collected. The median PM(2.5) and PM(10) levels during the exposure occasions in the road tunnel were 80 (range 41-93) μg/m(3) and 183 (72-213) μg/m(3) respectively. Irritative symptoms from the airways increased and PEF decreased after road tunnel exposure. Increased levels of IL-10, IL-12 and TNF-α were observed in NAL fluid from subjects without ongoing inhaled corticosteroid treatment. Forced expiratory volume in 1 s (FEV(1)) and the degree of bronchial responsiveness in asthmatics did not change significantly after tunnel exposure. We conclude that asthmatics exhibit increased symptoms, decreased PEF and signs of inflammatory response in the upper airways, after a 2 h road tunnel exposure. Our findings may further emphasize asthmatics as a vulnerable group to common air pollutants.
authors.affiliation: Department of Public Health Sciences, Division of Occupational and Environmental Medicine, Karolinska Institutet, Stockholm, Sweden. britt-marie.larsson@ki.se
authors.forename: Britt-Marie
authors.initials: BM
authors.lastname: Larsson
authors.forename: Johan
authors.initials: J
authors.lastname: Grunewald
authors.forename: C Magnus
authors.initials: CM
authors.lastname: Sköld
authors.forename: Anders
authors.initials: A
authors.lastname: Lundin
authors.forename: Thomas
authors.initials: T
authors.lastname: Sandström
authors.forename: Anders
authors.initials: A
authors.lastname: Eklund
authors.forename: Magnus
authors.initials: M
authors.lastname: Svartengren
mesh_terms: D000293:Adolescent; D000328:Adult; D000393:Air Pollutants / Q000378:metabolism* / Q000633:toxicity; D000403:Airway Resistance / Q000502:physiology*; D001249:Asthma / Q000150:complications / Q000503:physiopathology*; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D008297:Male; D008875:Middle Aged; D017817:Nasal Lavage Fluid / Q000737:chemistry*; D009569:Nitric Oxide / Q000009:adverse effects / Q000378:metabolism*; D012129:Respiratory Function Tests; D013183:Sputum / Q000378:metabolism*; D001335:Vehicle Emissions / Q000633:toxicity; D055815:Young Adult
chemical_list: D000393:Air Pollutants; D001335:Vehicle Emissions; D009569:Nitric Oxide