Analysis of PM2.5, black carbon, and trace metals measurements from the Kansas City Transportation and Local-Scale Air Quality Study (KC-TRAQS)

Abstract

Communities near transportation sources can be impacted by higher concentrations of particulate matter (PM) and other air pollutants. Few studies have reported on air quality in complex urban environments with multiple transportation sources. To better understand these environments, the Kansas City Transportation and Local-Scale Air Quality Study (KC-TRAQS) was conducted in three neighborhoods in Southeast Kansas City, Kansas. This area has several emissions sources including transportation (railyards, vehicles, diesel trucks), light industry, commercial facilities, and residential areas. Stationary samples were collected for 1-year (October 24, 2017, to October 31, 2018) at six sites using traditional sampling methods and lower-cost air sensor packages. This work examines PM less than 2.5 μm in diameter (PM_2.5), black carbon (BC), and trace metals data collected during KC-TRAQS. PM_2.5 filter samples showed the highest 24-h mean concentrations (9.34 μg/m³) at the sites located within 20-50 m of the railyard. Mean 24-h PM_2.5 concentrations, ranging from 7.96 to 9.34 μg/m³, at all sites were lower than that of the nearby regulatory site (9.83 μg/m³). Daily maximum PM_2.5 concentrations were higher at the KC-TRAQS sites (ranging from 25.31 to 43.76 μg/m³) compared to the regulatory site (20.50 μg/m³), suggesting short-duration impacts of localized emissions sources. Across the KC-TRAQS sites, 24-h averaged PM_2.5 concentrations from the sensor package (P-POD) ranged from 3.24 to 5.69 µg/m³ showing that, out-of-the-box, the PM sensor underestimated the reference concentrations. KC-TRAQS was supplemented by elemental and organic carbon (EC/OC) and trace metal analysis of filter samples. The EC/OC data suggested the presence of secondary organic aerosol formation, with the highest mean concentrations observed at the site within 20 m of the railyard. Trace metals data showed daily, monthly, and seasonal variations for iron, copper, zinc, chromium, and nickel, with elevated concentrations occurring during the summer at most of the sites.Implications: This work reports on findings from a year-long air quality study in Southeast Kansas City, Kansas to understand micro-scale air quality in neighborhoods impacted by multiple emissions sources such as transportation sources (including a large railyard operation), light industry, commercial facilities, and residential areas. While dozens of studies have reported on air quality near roadways, this work will provide more information on PM_2.5, black carbon, and trace metals concentrations near other transportation sources in particular railyards. This work can also inform additional field studies near railyards.

Figure 1.

KC-TRAQS Area of Interest (AOI) and Measurement Sites.

Figure 2a-g.

Monthly concentrations (in ng/m³) of Fe, Cu, Zn, Cr, Ni, Ca, and S across the KC-TRAQS sites.

Figure 3a-e:

Daily Concentration Trends of Fe, Cu, Zn, Cr, and Ni across the KC-TRAQS sites during May 2018.