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Airborne particles of the California Central Valley alter the lungs of healthy adult rats.

Smith KR; Kim S; Recendez JJ; Teague SV; Menache MG; Grubbs DE; Sioutas C; Pinkterton KE
Environ Health Perspect 2003 Jun; 111(7):902-908
Epidemiologic studies have shown that airborne particulate matter (PM) with a mass median aerodynamic diameter < 10 microm (PM10) is associated with an increase in respiratory-related disease. However, there is a growing consensus that particles < 2.5 microm (PM2.5), including many in the ultrafine (< 0.1 microm) size range, may elicit greater adverse effects. PM is a complex mixture of organic and inorganic compounds; however, those components or properties responsible for biologic effects on the respiratory system have yet to be determined. During the fall and winter of 2000-2001, healthy adult Sprague-Dawley rats were exposed in six separate experiments to filtered air or combined fine (PM2.5) and ultrafine portions of ambient PM in Fresno, California, enhanced approximately 20-fold above outdoor levels. The intent of these studies was to determine if concentrated fine/ultrafine fractions of PM are cytotoxic and/or proinflammatory in the lungs of healthy adult rats. Exposures were for 4 hr/day for 3 consecutive days. The mean mass concentration of particles ranged from 190 to 847 microg/m3. PM was enriched primarily with ammonium nitrate, organic and elemental carbon, and metals. Viability of cells recovered by bronchoalveolar lavage (BAL) from rats exposed to concentrated PM was significantly decreased during 4 of 6 weeks, compared with rats exposed to filtered air (p< 0.05). Total numbers of BAL cells were increased during 1 week, and neutrophil numbers were increased during 2 weeks. These observations strongly suggest exposure to enhanced concentrations of ambient fine/ultrafine particles in Fresno is associated with mild, but significant, cellular effects in the lungs of healthy adult rats.
Airborne-particles; Laboratory-animals; Animals; Animal-studies; Epidemiology; Respiratory-system-disorders; Diseases; Particulates; Particle-aerodynamics; Organic-compounds; Biological-effects; Exposure-levels; Exposure-assessment; Lung-disorders; Pulmonary-system-disorders; Nanotechnology
K.R. Smith, Center for Health and the Environment, University of California, One Shields Ave., Davis, CA 95616 USA
Publication Date
Document Type
Journal Article
Email Address
Funding Amount
Funding Type
Cooperative Agreement
Fiscal Year
Identifying No.
Issue of Publication
Priority Area
Work Environment and Workforce: Special Populations
Source Name
Environmental Health Perspectives
Performing Organization
University of California, Davis, California
Page last reviewed: September 2, 2020
Content source: National Institute for Occupational Safety and Health Education and Information Division