Controlled exposures of volunteers to respirable carbon and sulfuric acid aerosols

Journal Article · Mon Jun 01 00:00:00 EDT 1992 · Journal of the Air and Waste Management Association; (United States)

DOI:https://doi.org/10.1080/10473289.1992.10467028· OSTI ID:7159175

Anderson, K R; Avol, E L; Edwards, S A; Shamoo, D A; Peng, Ruchuan; Linn, W S; Hackney, J D ^[1]

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1. Univ. of Southern California, Downey (United States)

Respirable carbon or fly ash particles are suspected to increase the respiratory toxicity of coexisting acidic air pollutants, by concentrating acid on their surfaces and so delivering it efficiently to the lower respiratory tract. To investigate this issue, the authors exposed 15 healthy and 15 asthmatic volunteers in a controlled-environment chamber to four test atmospheres: (1) clean air; (2) 0.5-{mu}m H{sub 2}SO{sub 4} aerosol at {approx}100 {mu}g/m{sup 3}, generated from water solution; (3) 0.5-{mu}m carbon aerosol at {approx}250 {mu}g/m{sup 3}, generated from highly pure carbon black with specific surface area comparable to ambient pollution particles; and (4) carbon as in (3) plus {approx}100 {mu}g/m{sup 3} of ultrafine H{sub 2}SO{sub 4} aerosol generated from fuming sulfuric acid. Electron microscopy showed that nearly all acid in (4) became attached to carbon particle surfaces, and that most particles remained in the sub-{mu}m size range. Exposures were performed double-blind, 1 week apart. They lasted 1 hr each, with alternate 10-min periods of heavy exercise (ventilation {approx}50 L/min) and rest. Subjects gargled citrus juice before exposure to suppress airway ammonia. Lung function and symptoms were measured pre-exposure, after initial exercise, and at end-exposure. Bronchial reactivity to methacholine was measured after exposure. Statistical analyses tested for effects of H{sub 2}SO{sub 4} or carbon, separate or interactive, on health measures.

• OSTI ID: 7159175
• Journal Information: Journal of the Air and Waste Management Association; (United States), Vol. 42:6; ISSN 1047-3289
• Country of Publication: United States
• Language: English

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LUNGS
SENSITIVITY
PARTICULATES
HEALTH HAZARDS
SULFURIC ACID
AIR POLLUTION
ASTHMA
CONTROLLED ATMOSPHERES
ELECTRON MICROSCOPY
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MAMMALS
MICROSCOPY
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RESPIRATORY SYSTEM
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