Simulations using the Weather Research and Forecast modeling system with Chemistry (WRF-Chem-SMOKE) for northern Canada (Lu & Sokolik, 2013) and the western United States (Twohy et al., 2021) show that clouds significantly influenced by biomass burning smoke have increased cloud droplet number concentrations and decreased cloud droplet sizes. In this way, biomass burning particles can delay the onset of precipitation, affecting the lifetime, chemistry, and microphysical properties of clouds (