Comparison of wildfire smoke estimation methods and associations with cardiopulmonary‐related hospital admissions

Abstract

Climate forecasts predict an increase in frequency and intensity of wildfires. Associations between health outcomes and population exposure to smoke from Washington 2012 wildfires were compared using surface monitors, chemical‐weather models, and a novel method blending three exposure information sources. The association between smoke particulate matter ≤2.5 μm in diameter (PM 2.5 ) and cardiopulmonary hospital admissions occurring in Washington from 1 July to 31 October 2012 was evaluated using a time‐stratified case‐crossover design. Hospital admissions aggregated by ZIP code were linked with population‐weighted daily average concentrations of smoke PM 2.5 estimated using three distinct methods: a simulation with the Weather Research and Forecasting with Chemistry (WRF‐Chem) model, a kriged interpolation of PM 2.5 measurements from surface monitors, and a geographically weighted ridge regression (GWR) that blended inputs from WRF‐Chem, satellite observations of aerosol optical depth, and kriged PM 2.5 . A 10 μg/m 3 increase in GWR smoke PM 2.5 was associated with an 8% increased risk in asthma‐related hospital admissions (odds ratio (OR): 1.076, 95% confidence interval (CI): 1.019–1.136); other smoke estimation methods yielded similar results. However, point estimates for chronic obstructive pulmonary disease (COPD) differed by smoke PM 2.5 exposure method: a 10 μg/m 3 increase using GWR was significantly associated with increased risk of COPD (OR: 1.084, 95%CI: 1.026–1.145) and not significant using WRF‐Chem (OR: 0.986, 95%CI: 0.931–1.045). The magnitude (OR) and uncertainty (95%CI) of associations between smoke PM 2.5 and hospital admissions were dependent on estimation method used and outcome evaluated. Choice of smoke exposure estimation method used can impact the overall conclusion of the study.

Santa Ana Winds of Southern California Impact PM2.5With and Without Smoke From Wildfires

“…PM 2.5 also results from biomass burning and is the main component of wildfire smoke with the biggest impact on public health related to short‐term exposure (Gan et al, ; Gupta et al, ; Liu et al, ; McClure & Jaffe, ). In the United States, McClure and Jaffe () observed a downward trend in PM 2.5 during the last three decades, except in regions that were prone to wildfires.…”

Estimating the Health‐Related Costs of 10 Climate‐Sensitive U.S. Events During 2012

“…Climate change increases the likelihood of more wildfires and longer fire seasons in the U.S. through warmer temperatures, changes in seasonal rainfall patterns, and lower soil moisture (Abatzoglou & Williams, ; Liu et al, ). We analyzed health‐related costs for impacts of 2012 wildfires in Colorado and Washington documented in three peer‐reviewed studies (Alman et al, ; Fann et al, ; Gan et al, ) and mortality reports from the National Interagency Fire Center and a natural disaster risk management database (Munich RE NatCatSERVICE, ; U.S. National Interagency Fire Center, ). Fann et al () examined wildfire smoke‐attributable health impacts nationwide for 2008–2012, combining modeled fine particle (PM 2.5 ) concentrations and a set of exposure response functions using the BenMAP model (U.S. Environmental Protection Agency, ).…”

“…Alman et al () and Gan et al () investigated respiratory and cardiovascular morbidity endpoints during the peak burning periods in each state (from 5 June to 6 July in Colorado and 1 July to 31 October in Washington). Morbidity data were collected by the Colorado and Washington state health agencies for major respiratory ailments (asthma, upper respiratory infection, pneumonia, bronchitis, and chronic obstructive pulmonary disease) and cardiovascular outcomes (e.g., acute myocardial infarction).…”

The Associations Between Clinical Respiratory Outcomes and Ambient Wildfire Smoke Exposure Among Pediatric Asthma Patients at National Jewish Health, 2012–2015

“…Wildfires emit particulate matter, carbon monoxide, ozone precursors, and other air pollutants that adversely impact human health. These impacts have been shown to include increased all‐cause mortality (Johnston et al, ) and low birth weight (Holstius et al, ) as well as emergency department (B. L. Alman, ; Wettstein et al, ) and hospital admissions (B. L. Alman, ; Gan et al, ; Rappold et al, ) for respiratory (Henderson et al, ; J. C. Liu et al, ) and cardiovascular (Martin et al, ) symptoms, although overall evidence is strongest for respiratory outcomes (Gan et al, ; J. C. Liu, Pereira, et al, ; Reid et al, ). A survey of one fire‐impacted Australian community exposed to forest fire smoke found 70% of respondents reported health effects due to the fire and 5% sought medical treatment (Henderson & Johnston, ).…”