Fig. 2From: Spatial associations of long-term exposure to diesel particulate matter with seasonal and annual mortality due to COVID-19 in the contiguous United StatesSpatial distribution of COVID-19 mortality rate for (a, top left) January-May, (b, top right) June-September, (c, bottom left) October-December, and (d, bottom right) all of 2020. The R Statistical Software version 4.0.5 was used to produce the maps, using the package latticeBack to article page