Document Detail


Oxidant and acid aerosol exposure in healthy subjects and subjects with asthma. Part II: Effects of sequential sulfuric acid and ozone exposures on the pulmonary function of healthy subjects and subjects with asthma.
MedLine Citation:
PMID:  7848587     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
These studies were undertaken to evaluate pulmonary responses of humans sequentially exposed to acidic aerosols and ozone at levels that could reasonably be encountered in actual environmental exposures. Subjects first were exposed to sulfuric acid (H2SO4) aerosol to sensitize the airways to ozone. The exposure protocols were designed to provide more quantitative information about the threshold levels of ozone that produce adverse biological effects and to provide exposure-response data on ozone. Two groups of 30 nonsmoking volunteers of both sexes, between the ages of 18 and 45 years, were recruited. The healthy study population comprised 16 men and 14 women with an average age of 28 years and no airway hyperreactivity. The second group comprised 10 men and 20 women comparable in age to the control group, but with allergic asthma and positive skin tests. The study examined an exposure-response relationship using three levels of ozone ranging from below the current standard to one and one-half times the ambient air quality standard (0.08, 0.12, and 0.18 ppm* [parts per million]) with preexposure 24 hours earlier to H2SO4 (100 micrograms/m3) or sodium chloride (NaCl) (control) aerosol in a 45-m3 environmental chamber. The study used an incomplete block design in which each subject was exposed to four of the six paired experimental atmospheres. Both the selection of paired exposures and the order in which they were presented were randomized. The exposure protocol required nine days: Day 1, training and baseline preexposure measurements; Day 2, the first of the three-hour particle (H2SO4 or NaCl) exposures; Day 3 (24 hours after Day 2), ozone exposure at 0.08, 0.12, or 0.18 ppm for three hours; Day 4 (two to four weeks later), exposure to the same ozone concentration as on Day 4. After at least another two weeks, Days 6, 7, 8, and 9 repeated Days 2, 3, 4, and 5 using a second ozone concentration. All three-hour exposures included several predetermined periods of exercise and pulmonary function measurements. To examine for delayed effects, pulmonary function tests were measured two and four hours after exposure on the ozone days. Data were analyzed over the time course of exposure and by exposure level of ozone at each time point to reveal dose-response relationships more closely. The main findings of the study are as follows. No significant symptomatic or physiologic effects of exposure to either aerosol or ozone on lung function were found for the healthy group.(ABSTRACT TRUNCATED AT 400 WORDS)
Authors:
M J Utell; M W Frampton; P E Morrow; C Cox; P C Levy; D M Speers; F R Gibb
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Publication Detail:
Type:  Clinical Trial; Journal Article; Randomized Controlled Trial; Research Support, U.S. Gov't, Non-P.H.S.    
Journal Detail:
Title:  Research report (Health Effects Institute)     Volume:  -     ISSN:  1041-5505     ISO Abbreviation:  Res Rep Health Eff Inst     Publication Date:  1994 Nov 
Date Detail:
Created Date:  1995-03-14     Completed Date:  1995-03-14     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  8812230     Medline TA:  Res Rep Health Eff Inst     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  37-93, discussion 95-112     Citation Subset:  IM    
Affiliation:
Department of Medicine, University of Rochester School of Medicine and Dentistry, NY 14642.
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MeSH Terms
Descriptor/Qualifier:
Adolescent
Adult
Aerosols
Air Pollutants / adverse effects*
Asthma / physiopathology*
Bronchial Hyperreactivity / physiopathology
Bronchial Spasm / physiopathology
Dose-Response Relationship, Drug
Female
Forced Expiratory Volume / drug effects
Humans
Hypersensitivity / physiopathology
Lung / drug effects*,  physiopathology*
Male
Middle Aged
Oxidants / administration & dosage,  adverse effects*
Ozone / administration & dosage,  adverse effects*
Physical Exertion / physiology
Sulfuric Acids / administration & dosage,  adverse effects*
Vital Capacity / drug effects
Chemical
Reg. No./Substance:
0/Aerosols; 0/Air Pollutants; 0/Oxidants; 0/Sulfuric Acids; 10028-15-6/Ozone

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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