Personal Exposures to and Spatial Variations of Air Toxics in a “Hot Spot” in Camden, New Jersey

PJ Lioy, Z Fan, J Zhang, P Georgopoulos, SW Wang, PA Ohman, JL Held, and LJ Bonanno
Environmental and Occupational Health Sciences Institute–Robert Wood Johnson Medical School–UMDNJ and Rutgers University, Piscataway; the New Jersey, Department of Environmental Protection, Trenton, New Jersey, USA

The study characterized personal exposures and ambient concentrations of air toxics in a “hot spot” area - The Village of Waterfront South (WFS), and an urban reference site, Copewood/ Davis Streets area (CDS), in Camden, NJ. Personal exposure and residential ambient air
measurements, along with statistical analyses and exposure modeling, examined the impact of local industrial and mobile sources, particularly diesel exhausts. Personal (5 non-smoking subjects from WFS and 53 from CDS) and ambient air samples from a fixed monitoring site in each neighborhood were collected for 2 hours and measured VOCs, aldehydes, 6 PAHs, and PM2.5. Three “Spatial Saturation Sampling” campaigns were
conducted to monitor VOC and aldehyde concentrations for 2 - 8 hours at 22 and 6 gridbased sampling sites in WFS and in CDS, respectively.
Results showed that ambient PM2.5 (3 .3± 2.5 µg/m3), toluene ( .2 ±5.23 µg/m3), and benzo(a)pyrene (0.36±0. 5 ng/m3) were significantly higher (p <0.05) in WFS than in CDS. High concentrations of 60 µg/m3 for toluene and 59 µg/m3 for MTBE were found in areas close to local stationary sources in WFS during the spatial variation study. Great spatial variability BTEX and MTBE was observed in WFS, indicating impact of local sources. Similar
mean concentrations of benzene and MTBE and a good correlation (R>0.6) between these two compounds in WFS and CDS suggested automobiles as main sources. Formaldehyde and acetaldehyde were high in both WFS and CDS (e.g. mean concentrations of formaldehyde were > 20 µg/m3 in both locations), suggesting a large impact from local diesel truck traffic for formaldehyde and acetaldehyde pollution.
Personal concentrations of toluene (25. ± 3.5 µg/m3) and acrolein ( .78±3.7 µg/m3) were higher in WFS than in CDS ( 3. ± 5.3 µg/m3 for toluene and .27±2.36 µg/m3 for acrolein). The higher personal levels of some compounds (e.g. benzene) in CDS partially resulted from ETS or occupational exposure.
The simulated ambient concentrations of benzene and toluene using dispersion models were generally consistent with the ambient measurements within a factor of 2, but underestimated at the high-end percentiles. The modeled ambient concentrations of formaldehyde only accounted for -20 % of the ambient measurements, which was partially due to the underestimation of emission from local traffic. The source attributions showed that mobile sources are the major contributors to e ambient levels of benzene and formaldehyde, while both mobile and stationary sources contributed equally to toluene. Personal exposure modeling using the Individual Based Exposure Modeling application of the MENTOR system showed
that the modeled benzene and formaldehyde personal concentrations based on the ambient measurements were comparable to the personal measurements, suggesting strong impacts from local ambient sources. However, the modeled toluene personal concentrations were
consistently lower than the personal measurements, suggesting the strong influences of indoor sources.
In conclusion, this study demonstrated that WFS is a “hot spot” for specific air toxics. The“Spatial Saturation Sampling” was essential for increasing understanding of the spatial distribution of air toxics and identifying the sources of concerns. The sampling and modeling approaches implemented provide valuable tools for future in “hot spot” health studies and control strategies.

http://www.healtheffects.org/Pubs/AnnualConferenceProgram2008.pdf (page 37)