Personal and Ambient Exposures to Air Toxics in Camden, New Jersey

EPA Grant Number: R834677C160
Subproject: this is subproject number 160 , established and managed by the Center Director under grant R834677
(EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).

Center: Health Effects Institute (2010 — 2015)
Center Director: Greenbaum, Daniel S.
Title: Personal and Ambient Exposures to Air Toxics in Camden, New Jersey
Investigators: Lioy, Paul J.
Institution: Environmental and Occupational Health Sciences Institute , Health Effects Institute (HEI)
EPA Project Officer: Chung, Serena
Project Period: April 1, 2010 through March 31, 2015
RFA: Health Effects Institute (2010) RFA Text |  Recipients Lists
Research Category: Health Effects , Air Quality and Air Toxics , Air


Air toxics comprise a large and diverse group of air pollutants that, with sufficient exposure, are known or suspected to cause adverse effects on human health. The Clean Air Act requires the U.S. Environmental Protection Agency to characterize, prioritize, and address the effects of air toxics on public health and the environment.

Although ambient concentrations of some of these air toxics have been monitored by state or local agencies in some areas, the characterization of personal exposures to air toxics has been limited. And although ambient concentrations are generally low, so-called hot spots might exist where concentrations of one or more air toxics, and consequent exposures of area populations, could be elevated. In 2003, HEI targeted research to identify and characterize potential air toxics hot spots, with the aim of conducting future health studies in these locations.


Dr. Paul J. Lioy of the Environmental and Occupational Health Sciences Institute of Piscataway, New Jersey, and colleagues evaluated ambient and personal exposures to particulate matter with aerodynamic diameter ≤ 2.5 μm (PM2.5) and several air toxics in 107 nonsmoking residents of two neighborhoods in Camden, New Jersey. Residents of both neighborhoods were predominantly low-income. The investigators hypothesized that one neighborhood, Waterfront South, was an air toxics hot spot, defined as having elevated concentrations of air toxics compared with those of a nearby area. Waterfront South has numerous industrial sites serviced by heavy truck traffic and is close to major roads; its residents were thus likely to be exposed to air toxics from multiple sources. The other neighborhood, Copewood–Davis, was selected as the control, or comparison, site for thepollutant measurements. It was near Waterfront South and had no industrial sites.

Between June 2004 and July 2006 the investigators collected four sets of 24-hour personal air samples from the study subjects and made simultaneous measurements of ambient pollutant concentrations at a fixed monitoring site in each neighborhood. To assess how pollutant concentrations varied by season, they collected personal and ambient samples in summer and in winter. To assess how mobile sources (particularly truck traffic) contributed to pollutant concentrations, they collected personal and ambient samples on weekdays and weekend days (anticipating that concentrations would be higher on weekdays). To assess finer spatial variability in air toxics concentrations, they also conducted a saturation-sampling substudy in which pollutant measurements were made at 38 monitoring sites in the two neighborhoods. Lioy and colleagues measured concentrations of multiple air toxics, including volatile organic compounds (VOCs) (especially benzene, toluene, ethylbenzene, m- & p-xylenes, o-xylenes, methyl tert-butyl ether [MTBE], chloroform, carbon tetrachloride, and hexane); aldehydes (especially formaldehyde and acetaldehyde); and polycyclic aromatic hydrocarbons (PAHs) (especially naphthalene, phenanthrene, pyrene, and benzo[a]pyrene as representatives of compounds with two to five benzene rings). They also measured PM 2.5 concentrations.

In addition to comparing concentrations of air pollutants in Waterfront South with those in Copewood–Davis, the investigators used an alternative definition of a hot spot — i.e., having elevated concentrations of air toxics compared with those of other, more distant areas in New Jersey and across the United States — to compare concentrations of air pollutants in Waterfront South and Copewood–Davis with concentrations at other locations.

Expected Results:

The investigators reported that one of the neighborhoods, Waterfront South, had consistently higher ambient concentrations than the other, Copewood–Davis, of PM2.5, toluene, xylenes, and PAHs. Thus, by the investigators’ original definition of a hot spot (i.e., having elevated concentrations compared with those of a nearby control, or comparison, area with fewer industrial sites), Waterfront South could be considered a hot spot for these pollutants. However, ambient concentrations in Copewood–Davis of several other pollutants — benzene, MTBE, chloroform, carbon tetrachloride, hexane, and acetaldehyde — were as high as or higher than those in Waterfront South. The Committee generally considered the measurements of the air pollutants to have been accurate and reliable. However, they were concerned about the validity of the absolute concentrations of benzene, formaldehyde, and acetaldehyde, because they were much higher than those reported in other studies, and there appeared to be some specific problems with the measurement method for formaldehyde.

In summary, the current study provided valuable information about ambient and personal concentrations of PM2.5 and a large number of air toxics and demonstrated elevated ambient concentrations (compared with other areas in New Jersey and across the United States) of some air toxics in both of these lower-socioeconomic-status neighborhoods. At the same time, the findings illustrate the difficulties of defining an area a priori as a potential hot spot — or as a control location. The design of future exposure and health effects studies in hot spots will need to take multiple pollutant sources and meteorologic factors into consideration to achieve sufficient contrasts in pollutant concentrations between appropriately chosen hot spots and background locations

Supplemental Keywords:

Health Effects, Air Quaiity, benzene, particulate matter, air toxics hot spots;

Relevant Websites: Exit

Main Center Abstract and Reports:

R834677    Health Effects Institute (2010 — 2015)

Subprojects under this Center: (EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
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