Air pollution from wildfires and human health vulnerability in Alaskan communities under climate change

Abstract

Alaskan wildfires are becoming more frequent and severe, but very little is known regarding exposure to wildfire smoke, a risk factor for respiratory and cardiovascular illnesses. We estimated long-term, present-day and future exposure to wildfire-related fine particulate matter (PM 2.5 ) across Alaska for the general population and subpopulations to assess vulnerability using observed data for the present day (1997–2010), modelled estimates for the present day (1997–2001), and modelled estimates for the future (2047–2051). First, we assessed wildfire-PM 2.5 exposure by estimating monthly-average wildfire-specific PM 2.5 levels across 1997–2010 for 158 Alaskan census tracts, using atmospheric transport modelling based on observed area-burned data. Second, we estimated changes in future (2047–2051) wildfire-PM 2.5 exposure compared to the present-day (1997–2001) by estimating the monthly-average wildfire-specific PM 2.5 levels for 29 boroughs/census areas (county-equivalent areas), under the Intergovernmental Panel on Climate Change (IPCC) A1B scenario from an ensemble of 13 climate models. Subpopulation risks for present and future exposure levels were estimated by summing area-weighted exposure levels utilizing the 2000 Census and State of Alaska’s population projections. We assessed vulnerability by several subpopulation characteristics (e.g. race/ethnicity, urbanicity). Wildfire-PM 2.5 exposure levels during 1997–2010 were highest in interior Alaska during July. Among subpopulations, average summer (June-August) exposure levels for urban dwellers and African-American/Blacks were highest at 9.1 μg m −3 and 10 μg m −3 , respectively. Estimated wildfire-PM 2.5 varied by Native American tribe, ranging from average summer levels of 2.4 μg m −3 to 13 μg m −3 for Tlingit-Haida and Alaskan Athabascan tribes, respectively. Estimates indicate that by the mid-21st century, under climate change, almost all of Alaska could be exposed to increases of 100% or more in levels of wildfire-specific PM 2.5 levels. Exposure to wildfire-PM 2.5 likely presents a substantial public health burden in the present day for Alaska communities, with different impacts by subpopulation. Under climate change, wildfire smoke could pose an even greater public health risks for most Alaskans.

Wildfire Smoke Is Associated With an Increased Risk of Cardiorespiratory Emergency Department Visits in Alaska

“…There is some evidence of increased risk of hospitalization for respiratory illness associated with WFS among African-Americans in the western U.S. , and among Indigenous people in Australia (Hanigan et al, 2008). A recent modeling study found that because of their geographic distribution in areas of high WFS concentration in Interior Alaska, African-Americans and Alaskan Athabascans may be more likely to be exposed (Woo et al, 2020). This is the first study to show an increased risk of adverse health outcomes associated with WFS among Alaska Native people.…”

Social vulnerability indicators to the Health Impacts of Climate Change: A Scoping Review

“…Multiple social vulnerability indices include race or ethnicity based indicators for social vulnerability which have been found to be good predictors of susceptibility to heat (21,22,26,32,37,44,46,58,72,95,98,111,116,119,(158)(159)(160)(161)(162)(163)(164). This is attributed to the history of structural disadvantage and discrimination faced by minority communities (111,112).…”

“…There are several indicators that measure socioeconomic status at individual and area levels, including household income (28,36,50,53,70,136,148,(166)(167)(168)(169)(170), neighborhood deprivation (105,137,144), labor force participation (42,48,148), poverty (22,24,48,58,62,70,72,73,81,85,89,90,93,95,98,100,102,111,112,116,162,(171)(172)(173), gross domestic product (174)(175)(176), income inequality (172,176,177), unemployment (41,49,…”

“…The spatial distribution of human populations in urban, sub-urban, and rural areas increases vulnerability to the health impacts of climate change (16,48,49,59,62,67,70,90,91,94,96,98,105,109,116,118,144,149,162,168,172,187,193,194). Urban and sub-urban areas have higher population densities (25,41,45,48,58,62,75,98,105,109,113,119,127,151,162,171,178,(196)(197)(198)(199)(200)(201) and larger population sizes (98,202,203...…”

Homeowner Preferences for Wildfire Risk Mitigation in the Alaskan Wildland Urban Interface

“…Climate change has already begun to intensify wildfire activity in portions of the western United States and is anticipated to continue increasing activity in the coming years [4]. Alaska's forests are anticipated to burn more severely, be susceptible to more fire danger days, and smoke from wildfires is expected to pose an increased risk to Alaskans under potential future climate scenarios [5][6][7][8]. The Intergovernmental Panel on Climate Change (IPCC) identifies how climate change affects wildfire regimes including increased risk and severity [9].…”