Fig. 3. Total suspended particulates (TSP) at the ground vs. total lidar backscatter approximately 3 m above the ground. The linear fit is forced to an intercept equal to the background TSP. The result is a slope of 0.0034 and an r2 value of 0.79. The particulate matter with diameter less than 10 µm (PM10) fit is 0.0025 with a zero intercept and an r2 of 0.61.