Skip to main content
. 2019 May 10;16(9):1634. doi: 10.3390/ijerph16091634

Figure 3.

Figure 3

Denver near-road PM2.5 increment and pollution rose. (a) Hourly (thin orange line) and 24-hr PM2.5 concentrations (μg/m3, thick colored lines) at the near-road and nearby sites during February 2014, and the difference between 24-hr PM2.5 concentrations (μg/m3) at the near-road site and the nearby CAMP monitoring site (black line). (b) Pollution rose for hourly PM2.5 concentrations (µg/m3) at the Denver near-road site in February 2014. The size of each wedge indicates the frequency of wind direction. (For example, winds were out of the northeast nearly 25% of the time.) Color bands indicate the relative fraction of the time that concentrations occurred for each wind direction. For example, when winds were from the northeast, concentrations of 10–20 µg/m3 were most frequent, followed by concentrations of 20–30 µg/m3.