Characterization ofPM2.5at a traffic site using several integrated analytical techniques

We have conducted a comprehensive, year-long, sampling campaign for particulate matter (PM) at a site near a major highway, following standard protocols. Total mass, elemental and chemical composition of the fine fractions (PM2.5) of particulates originating from traffic are determined using several complementary techniques. These complementary techniques include gravimetric analysis, X-ray fluorescence, scanning electron microscopy and energy dispersive spectroscopy, X-ray diffraction (XRD) and black carbon multiwavelength absorption. Conducting an enrichment factor analysis and correlation coefficient calculations on elements show that Si, Ca, Al, Fe, Ti, Mn, Mg, K, Na and Cr are of crustal origin, while P, Cl and V are enriched slightly from human activities. All other measured elements (Rb, Zr, Ba, Sr, S, Ni, Cu, Zn and Pb) have high enrichment factors and relate to anthropogenic sources. Sulfates in the form of mascagnite and koktaite had the largest contribution to PM2.5(43% of total PM concentration). Natural pollutants such as quartz, calcite, iron oxide and aluminum oxide originating from the crust also contribute to PM2.5. eBC and elements such as Zn, Ba, Cu, Fe and S are related to traffic emissions such as exhaust emissions and tire, brakes and road erosion. Correlation coefficients and enrichment factor calculations helped identify elements that are related to natural emissions and those related to anthropogenic sources. Being an arid region, the PM(2.5)mass concentrations were found to be within or slightly above international air quality standards.

Automated summary

This study comprehensively analyzed PM2.5 originating from traffic using various techniques to determine its elemental and chemical composition. The research found that crustal elements make up a major portion of PM2.5, while some elements are derived from human activities. The study also revealed that traffic emissions are a significant source of PM2.5.