Where do particulate toxins reside? An improved paradigm for the structure and dynamics of the urban mid-Atlantic aerosol

Journal Article · Tue Sep 01 04:00:00 EDT 1998 · Environmental Science and Technology

DOI:https://doi.org/10.1021/es971067y· OSTI ID:655396

Ondov, J M ^[1]; Wexler, A S ^[2]

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1. Univ. of Maryland, College Park, MD (United States). Dept. of Chemistry and Biochemistry
2. Univ. of Delaware, Newark, DE (United States). Dept. of Mechanical Engineering

Discussions of excess mortality and morbidity from exposure to urban aerosol particles typically invoke the now 20-year-old trimodal aerosol paradigm proposed by Whitby to explain the structure and behavior of ambient aerosol volume and its major constituent, sulfate. However, this paradigm largely ignores the primary high-temperature combustion (HTC) components of the urban aerosol, which contribute minor amounts of the aerosol mass, but carry the bulk of the particulate toxins and numbers of aerosol particles. Studies encompassing the analyses of >100 size distributions of important intrinsic tracers of primary particles from HTC sources collected over the past decade in various environments show that urban aerosol contains a complex mixture of physically-discrete fresh and aged, primary particle populations from a variety of sources. Furthermore, whereas the behavior of fine-particulate aerosol mass and sulfate was described in terms of coagulation and accumulation aerosol scavenging of new secondary sulfate nuclei, studies reviewed herein suggest that the behavior of primary aerosol is mediated more by hygroscopic growth and cloud processing, accompanied by oxidation of SO{sub 2} on wet particles and droplets. The authors conclude that the distribution of airborne particulate toxins and their atmospheric behavior is far more complex than commonly conceptualized on the basis of the classical trimodal model, and they develop an extended paradigm in which the focus is on the primary accumulation aerosol.

• OSTI ID: 655396
• Journal Information: Environmental Science and Technology, Journal Name: Environmental Science and Technology Journal Issue: 17 Vol. 32; ISSN ESTHAG; ISSN 0013-936X
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
AIR POLLUTION
ATMOSPHERIC CHEMISTRY
MATHEMATICAL MODELS
PARTICULATES
SULFATES
SULFUR DIOXIDE
TOXIC MATERIALS
URBAN AREAS