title: Exposures of healthy and asthmatic volunteers to concentrated ambient ultrafine particles in Los Angeles.
abstract: Adult volunteers (17 healthy, 14 asthmatic) were exposed in a controlled environmental chamber to concentrated ultrafine particles (UFP) collected in a Los Angeles suburb with substantial motor vehicle pollution. Exposures lasted 2 h with intermittent exercise. Inhaled particle counts (mean 145,000/cm(3), range 39,000-312,000) were typically 7-8 times higher than ambient levels. Mass concentrations (mean 100 microg/m(3), range 13-277) were not highly correlated with counts. Volunteers were evaluated for lung function, symptoms, exhaled nitric oxide (eNO), Holter electrocardiography, and inflammatory markers in peripheral blood and induced sputum. Relative to control (filtered air) studies, UFP exposures were associated with a 0.5% mean fall in arterial O(2) saturation estimated by pulse oximetry (p < .01), a 2% mean fall in forced expired volume in 1 sec (FEV(1)) the morning after exposure (p < .05), and a transient slight decrease in low-frequency (sympathetic) power in Holter recordings during quiet rest (p < .05). Healthy and asthmatic subjects were not significantly different across most endpoints. Thus, this initial experimental study of human volunteers exposed to concentrated Los Angeles area ambient UFP showed some acute deleterious cardiopulmonary responses, which, although generally small and equivocal as in previous studies of larger sized concentrated ambient particles, might help to explain reported adverse health effects associated with urban particulate pollution.
authors.affiliation: Keck School of Medicine, University of Southern California, Los Angeles, California, USA.
authors.forename: Henry
authors.initials: H
authors.lastname: Gong
authors.forename: William S
authors.initials: WS
authors.lastname: Linn
authors.forename: Kenneth W
authors.initials: KW
authors.lastname: Clark
authors.forename: Karen R
authors.initials: KR
authors.lastname: Anderson
authors.forename: Constantinos
authors.initials: C
authors.lastname: Sioutas
authors.forename: Neil E
authors.initials: NE
authors.lastname: Alexis
authors.forename: Wayne E
authors.initials: WE
authors.lastname: Cascio
authors.forename: Robert B
authors.initials: RB
authors.lastname: Devlin
mesh_terms: D000293:Adolescent; D000328:Adult; D001249:Asthma / Q000139:chemically induced*; D001772:Blood Cell Count; D001774:Blood Chemical Analysis; D016022:Case-Control Studies; D015716:Electrocardiography, Ambulatory; D004781:Environmental Exposure; D005260:Female; D006801:Humans; D015141:Los Angeles; D008297:Male; D008875:Middle Aged; D009569:Nitric Oxide / Q000378:metabolism; D010092:Oximetry; D010316:Particle Size; D052638:Particulate Matter / Q000009:adverse effects*; D013147:Spirometry; D013183:Sputum / Q000737:chemistry / Q000166:cytology
chemical_list: D052638:Particulate Matter; D009569:Nitric Oxide