Atmospheric pollutant concentrations and leaf chemistry variables collected along gradients of median household income and traffic density in Salt Lake Valley, UT

<p>We utilize traffic density and <i>Convolvulus arvensis </i>leaf chemistry<i> </i>to understand spatial patterns linking atmospheric pollution and household income in the Salt Lake City metropolitan area, USA. We hypothesize that traffic density will explain variation in atmospheric NO_x and O₃ concentrations. In addition, we expect foliar <span>%N and nitrogen isotope ratios (</span>δ¹⁵N) to be elevated and carbon isotope ratios (δ¹³C) to be depleted on high traffic density roads<span>. These hypotheses were supported: we found the</span><span> highest</span><span> NO_x and lowest O₃ concentrations on high-traffic density roads. Also, NO_x concentrations were higher in low-income neighborhoods. Low-income neighborhoods contained a greater density of high-traffic roads than high-income neighborhoods. Foliar %N was highest in low-income neighborhoods and was correlated with NO_x and O₃</span>, while δ¹⁵N was more depleted with increasing O₃. These findings indicate that the distribution of high-traffic density roads plays a significant role in inequities in pollution exposure between high- and low-income neighborhoods, which is reflected in leaf chemistry.</p>