IMPACT OF HIGHWAYS, ROAD TYPES AND VEGETATION ON NITROGEN DIOXIDE CONCENTRATIONS IN NEIGHBORHOOD PLANNING UNIT V IN ATLANTA, GA

Nitrogen dioxide (NO₂) concentrations were measured within Neighborhood Planning Unit V in southern Atlanta, GA. NO₂ is known to cause respiratory disease and reacts within the atmosphere to form ozone, another respiratory irritant. Internal combustion engines within automobiles are a major source of NO₂ in urban environments. Two major interstate highways transect the sample area where the residents experience asthma rates five times greater than Atlanta’s average.

Measurements were taken to further record air quality within the sample area and to describe and quantify the impact of the following three variables on NO₂ concentrations within our study site: distance from the two interstate highways, nearby road type and surrounding vegetation. NO₂ concentrations were measured using 68 Ogawa passive samplers that were exposed for six days and dispersed in a systematically designed gridded pattern throughout the sample area. The sample area was selected with input from our community partner, South Atlanta for the Environment.

NO₂ levels during the week of sampling varied from 4.1 ppb to 12.2 ppb with an average concentration of 6.4 ppb. These levels are significantly below WHO and EPA standards. Mapping the data using ArcGIS showed a significant inverse relationship between NO2 concentrations and distance from I-75. Analysis showed that road usage had the largest impact on NO₂ concentrations and distance from I-75, which runs north-south, also lead to significant spatial variation. However, distance from I-20, which runs east-west, and surrounding vegetation had no significant impact on spatial variations of NO₂. North/northeast prevailing winds could have accounted for the differences in the impact of highways on NO₂ concentrations. These parameters were found to account for approximately 60% of the variation of NO₂ between the points.