Trace element concentrations in ambient air as a function of distance from road

Area of Science:

• Environmental Health
• Air Pollution Science
• Geospatial Analysis

Background:

• Traffic-related air pollution poses health risks.
• Logarithm of distance to road is often used as a proxy for traffic exposure in studies.
• Limited research validates this proxy and details the elemental composition of traffic-related particulate matter.

Purpose of the Study:

• To validate the use of logarithm of distance to road as a proxy for traffic-related particulate matter air pollution.
• To identify specific elements in particulate matter associated with proximity to roadways.
• To analyze the spatial patterns and elemental composition of traffic-related air pollution.

Main Methods:

• Air samples were collected using a mobile particle concentrator near major roadways in the Greater Boston Area.
• Elemental composition of coarse and fine particulate matter was analyzed.
• Statistical associations between elemental concentrations and logarithm of distance to road were examined.

Main Results:

• Concentrations of Cl, Ti, V, Cr, Mn, Fe, Co, Cu, Zn, Sr, Zr, Sn, Ba, and Pb in coarse particulate matter were significantly associated with the logarithm of distance to road.
• Al, Ca, Ti, Cr, Mn, Fe, Cu, and Zn in fine particulate matter were also significantly associated with the logarithm of distance to road.
• Road type (primary/highway vs. secondary) was not a significant predictor of traffic-related elements.

Conclusions:

• The logarithm of distance to road is a supported proxy for assessing traffic-related particulate matter air pollution exposure in epidemiological studies.
• Specific elements have been identified as indicators of traffic-related particulate matter.
• Further research can refine exposure assessment methods for traffic-related air pollution.