Boxplot of annual hydrocarbon and NO_x VMRs measured at the Floresville monitor site during July 2013 to July 2014. Horizontal bars are medians, crosses are averages, and open squares represent typical background VMRs (Helmig et al., 2009). For comparison, the range of mean VMRs in 28 cities presented by Baker et al. (2008) is given (brown bars), although 2013/14 VMRs in urban areas are likely lower (Warneke et al., 2012). All compounds showed right-skewed distributions and skewness is indicated across the top of the graph.