Ambient pollutant concentrations measured by a mobile laboratory in South Bronx, NY

Abstract The objective of this study is to characterize the ambient air quality of the South Bronx, New York City (NYC), having high concentrations of diesel trucks and waste transfer facilities. We employed a mobile laboratory for continuous measurements of concentrations of fine particulate matter (PM 2.5 ), black carbon (BC), and gaseous pollutants at 6 locations for three–four weeks each during the period of April 2001–February 2003. Integrated 24-hr PM 2.5 samples were also collected for elemental and PAHs analyses. South Bronx PM 2.5 and BC levels were compared to those at Bronx PS 154 (NYSDEC site) and at Hunter College in the Lower Manhattan. Although the median daily PM 2.5 concentrations agreed within 20%, the median hourly BC concentrations were higher at all South Bronx sites ranging from 2.2 to 3.8 μg m −3 , compared to 1.0–2.6 μg m −3 at Hunter College. Continuous Aethelometer measurements at additional 27 sampling sites in the South Bronx were conducted along major highways. BC concentrations varied within each site, depending on time-of-day, with a large spatial variability from site-to-site. Daily median BC concentrations varied from 1.7 to 12 μg m −3 on the weekdays, and were lower (0.50–2.9 μg m −3 ) on the weekends. Elemental concentrations were higher at all South Bronx sites than those at Hunter College for all measured elements but Ni and V, and at the Hunts Point, an industrial location, were approximately 2.5-fold higher. The average sum of 35 PAHs was 225 ng m −3 , which is 4.5 times larger than representative regional concentrations in Jersey City, NJ. Among the individual PAHs, 3,6-dimethylphenanthrene had the highest concentrations, and the overall PAH fingerprint differed from signal for Jersey City. Our data indicates that highways encircling the South Bronx are having a measurable adverse influence on residents’ exposure to pollutants compared to other NYC areas.