Differential Cardiopulmonary Health Impacts of Local and Long-Range Transport of Wildfire Smoke.

We estimated cardiopulmonary morbidity and mortality associated with wildfire smoke (WFS) fine particulate matter (PM 2.5 ) in the Front Range of Colorado from 2010 to 2015. To estimate WFS PM 2.5 , we developed a daily kriged PM 2.5 surface at a 15  × 15 km resolution based on the Environmental Protection Agency Air Quality System monitors for the western United States; we subtracted out local seasonal-average PM 2.5 of nonsmoky days, identified using satellite-based smoke plume estimates, from the local daily estimated PM 2.5 if smoke was identified by National Oceanic and Atmospheric Administration's Hazard Mapping System. We implemented time-stratified case-crossover analyses to estimate the effect of a 10 µg/m 3 increase in WFS PM 2.5 with cardiopulmonary hospitalizations and deaths using single and distributed lag models for lags 0-5 and distinct annual impacts based on local and long-range smoke during 2012, and long-range transport of smoke in 2015. A 10 µg/m 3 increase in WFS was associated with all respiratory, asthma, and chronic obstructive pulmonary disease hospitalizations for lag day 3 and hospitalizations for ischemic heart disease at lag days 2 and 3. Cardiac arrest deaths were associated with WFS PM 2.5 at lag day 0. For 2012 local wildfires, asthma hospitalizations had an inverse association with WFS PM 2.5 (OR: 0.716, 95% CI: 0.517-0.993), but a positive association with WFS PM 2.5 during the 2015 long-range transport event (OR: 1.455, 95% CI: 1.093-1.939). Cardiovascular mortality was associated with the 2012 long-range transport event (OR: 1.478, 95% CI: 1.124-1.944).