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document
Inflammatory response in humans exposed to 2.0 ppm nitrogen dioxide . Nitrogen dioxide ( NO2 ) is a common indoor air pollutant , especially in homes with unvented combustion appliances . Epidemiological studies suggest that children living in homes with unvented heating sources are more prone to respiratory infections than children living in homes with lower levels of NO2 . However , experimental studies in which human volunteers were exposed acutely to moderate levels of NO2 ( 0.5-2.0 ppm ) have shown little evidence of lung inflammation or decreased host resistance capacity . In the study reported here , 8 healthy volunteers were exposed to 2.0 ppm NO2 and to filtered air for 4 h while undergoing intermittent moderate exercise . Bronchoalveolar lavage was performed the following morning . The lavage was divided into a predominantly bronchial washing ( first 20 ml of lavage ; BL ) and a predominantly alveolar washing ( BAL ) . In the BL , NO2 exposure caused increases in polymorphonuclear neutrophils ( PMNs ) , interleukin 6 ( IL-6 ) , IL-8 , alpha1-antitrypsin , and tissue plasminogen activator , and decreases in epithelial cells . In the BAL , there were no NO2-induced changes in either cell numbers or soluble mediators . On the other hand , alveolar macrophages from BAL showed a decrease in the ability to phagocytose unopsonized Candida albicans and a decrease in superoxide production . No difference in susceptibility to virus infection was found between the NO2- and air-exposed macrophages . No changes in lung function were observed , but the aerosol bolus recovery technique revealed a statistically significant ( p < .05 ) decrease in the fraction of aerosol recovered following nitrogen dioxide exposure , which is suggestive of small obstructive changes induced by NO2 .
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Intervention_Pharmacological
nitrogen dioxide
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Intervention_Pharmacological
Nitrogen dioxide ( NO2 )
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Intervention_Pharmacological
NO2
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Intervention_Pharmacological
NO2
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Intervention_Pharmacological
NO2
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Intervention_Pharmacological
filtered air
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Intervention_Physical
undergoing intermittent moderate exercise
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Intervention_Surgical
Bronchoalveolar lavage
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Intervention_Pharmacological
NO2
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Intervention_Pharmacological
NO2-
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Intervention_Pharmacological
nitrogen dioxide
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Intervention_Pharmacological
NO2
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Outcome_Physical
NO2 exposure
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Outcome_Physical
polymorphonuclear neutrophils ( PMNs ) , interleukin 6 ( IL-6 ) , IL-8 , alpha1-antitrypsin , and tissue plasminogen activator
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Outcome_Physical
epithelial cells .
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Outcome_Physical
cell numbers or soluble mediators .
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Outcome_Physical
phagocytose unopsonized Candida albicans
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Outcome_Physical
superoxide production .
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Outcome_Physical
susceptibility to virus infection
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Participant_Condition
exposed to 2.0 ppm nitrogen dioxide
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Participant_Sample-size
8
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Participant_Condition
exposed to 2.0 ppm NO2 and to filtered air for 4 h
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Participant_Condition
intermittent moderate exercise