A comparison of ground-level air quality data with New York State Department of Environmental Conservation monitoring stations data in South Bronx, New York

The South Bronx is a low-income, minority community in New York City. It has one of the highest asthma rates in the country, which community residents feel is related to poor air quality. Community residents also feel that the air quality data provided by the New York State Department of Environmental Conservation (DEC) through its network of monitoring stations do not reflect the poor quality of the air they breathe. This is due to the fact that these monitoring stations are located 15 m above ground. In the year 2001 this project collected air quality data at three locations in the study area. They were collected close to ground-level at a height of 4 m by a mobile laboratory placed in a van as part of the South Bronx Environmental Health and Policy Study. This paper compares data collected by the project with data from DEC's monitoring stations in Bronx County during the same periods. The goal of the comparison is to gain a better understanding of differences in measured air quality concentrations at these different heights. Although there is good agreement in the data among DEC stations there are some important differences between ground-level measurements and DEC data. For PM_2.5 the measured concentrations by the van were similar to those recorded by DEC stations. In the case of ozone, the concentrations recorded at ground level were similar or lower than those recorded by DEC stations. For NO₂, however, the concentrations recorded at ground level were over twice as high as those recorded by DEC. In the case of SO₂, ground level measurements were substantially higher in August but very similar in the other two periods. CO concentrations measured at ground-level tend to be 60–90% higher than those recorded by DEC monitoring stations. Despite these differences, van measurements of SO₂ and CO concentrations were well below EPA standards.