Naturally occurring fogs in industrialized cities are contaminated by acidic air pollutants.
In Brussels, Belgium, the pH of polluted fogwater may be as low as 3 with osmolarity as low as 30 mOsm.
In order to explore short-term respiratory effects of a realistic acid-polluted fog, we collected samples of acid fog in Brussels, Belgium, which is a densely populated and industrialized city, we defined characteristics of this fog and exposed asthmatic volunteers at rest through a face mask to fogs with physical and chemical characteristics similar to those of natural fogs assessed in this urban area.
Fogwater was sampled using a screen collector where droplets are collected by inertial impaction and chemical content of fogwater was assessed by measurement of conductivity, pH, visible colorimetry, high pressure liquid chromatography, and atomic absorption spectrophotometry over a period of one year.
The fogwater composition was dominated by NH4+and S04=ions.
First we evaluated the possible effect of fog acidity alone.
For this purpose 14 subjects with asthma were exposed at rest for 1 hr [mass median aerodynamic diameter to a large-particle (MMAD), 9 mum] aerosol with H2SO4 concentration of 500 mug/m3 (pH 2.5) and osmolarity of 300 mOsm.
We did not observe significant change in pulmonary function or bronchial responsiveness to metacholine. (...)
Mots-clés Pascal : Brouillard, Acide, Milieu urbain, Belgique, Europe, Toxicité, Homme, Volontaire, Malade, Asthme, Court terme, Fonction respiratoire, Appareil respiratoire pathologie
Mots-clés Pascal anglais : Fog, Acids, Urban environment, Belgium, Europe, Toxicity, Human, Volunteer, Patient, Asthma, Short term, Lung function, Respiratory disease
Notice produite par :
Inist-CNRS - Institut de l'Information Scientifique et Technique
Cote : 97-0165420
Code Inist : 002B03M02. Création : 21/05/1997.