| We quantify how estimates of mortality in the United States attributable to ozone (O3) and fine particulate matter (PM 2.5) driven with modeled concentrations at coarse resolution differ from those at finer resolution. Modeled concentrations of O3 and PM2.5 were used to estimate mortalities at 12 km and coarser resolutions greater than that of global models. We estimate that 66,000 (95% CI, 44,700 -- 86,500) and 21,400 (5,600 -- 34,200) mortalities per year are attributable to PM2.5 and O3 concentrations above low-concentration thresholds, respectively. Coarse grid resolutions produce mortality estimates that are substantially biased low for PM2.5 (38% lower than the best estimate at >300 km resolution), but only 5% higher for O3 (at >96 km resolution). Mortality estimates for primary PM2.5 species were more affected by grid resolution than for secondary species. These results suggest that using coarse resolution global models (>100 km) are likely biased low for PM2.5, but with little error for ozone. |
