Figure 4
Trends in the PM2.5 mass injected above (a) 1 km, (b) 2 km, (c) 3 km, (d) 4 km, (e) 5 km, (f) 6 km, (g) 7 km, and (h) 8 km, by wildfires during the months of August and September of the years 2003–2020. N-values indicate the number of plumes out of the original ~ 4.6 million that remain above the threshold altitude. Only trends significant at p < 0.1 are displayed, with a crosshatch overlaid on trends with p < 0.05. Note the differences in the ranges represented by the color bars.
