Using wildland fire smoke modeling data in gerontological health research (California, 2007-2018)

Impacts of wildfire smoke PM2.5, greenspace and terrain ruggedness on life expectancy in the contiguous United States

Wildfire smoke PM2.5 has been associated with many adverse health effects. However, little is known about its impact on life expectancy. This study investigated the impact of wildfire smoke PM2.5 and its interaction with greenspace and terrain ruggedness on life expectancy in the contiguous United States. By analyzing life expectancy estimates during the 2010 to 2015 period in 66,263 census tracts with multi-level regression models adjusted for income, age, race, and population density, we found that life expectancy was negatively associated with the concentration of smoke PM2.5 and the number of smoke days. Specifically, the increase of 1 μg/m3 in the annual daily average smoke PM2.5 levels is associated with a decrease in life expectancy by 1.10 years (regression coefficient β = -1.10, 95 % confidence interval (CI): [-1.21, -0.99]). For every extra smoke day, life expectancy might decrease by 0.021 years (β = -0.021, 95 % CI: [-0.024, -0.018]). Additionally, the interaction of greenspace with smoke PM2.5 negatively affected life expectancy (β = -0.29, 95 % CI: [-0.38, -0.21]). No significant relationship was observed between life expectancy and terrain ruggedness. The generalized additive model revealed that the impact of smoke PM2.5 on life expectancy varied across concentration levels. The sensitivity analysis confirmed that the results were robust. Our study suggests that wildfires not only have a direct negative effect on life expectancy but also diminish the beneficial impact of greenspace, potentially turning its positive effects detrimental.

Clearing the Air: Understanding the Impact of Wildfire Smoke on Asthma and COPD

Wildfires are a global natural phenomenon. In North America, wildfires have not only become more frequent, but also more severe and longer in duration, a trend ascribed to climate change combined with large fuel stores left from modern fire suppression. The intensification of wildfire activity has significant implications for planetary health and public health, as exposure to fine particulate matter (PM2.5) in wildfire smoke is linked to adverse health effects. This review focuses on respiratory morbidity from wildfire smoke exposure. Inhalation of wildfire PM2.5 causes lung injury via oxidative stress, local and systemic inflammation, airway epithelium compromise, and increased vulnerability to infection. Wildfire PM2.5 exposure results in exacerbations of pre-existing asthma and chronic obstructive pulmonary disease, with an escalation in healthcare utilization, including emergency department visits and hospitalizations. Wildfire smoke exposure may be associated with asthma onset, long-term impairment of lung function, and increased all-cause mortality. Children, older adults, occupationally-exposed groups, and possibly women are the most at risk from wildfire smoke. Future research is needed to clarify best practices for risk mitigation and wildfire management.

Wildland Fires Worsened Population Exposure to PM2.5 Pollution in the Contiguous United States

As wildland fires become more frequent and intense, fire smoke has significantly worsened the ambient air quality, posing greater health risks. To better understand the impact of wildfire smoke on air quality, we developed a modeling system to estimate daily PM2.5 concentrations attributed to both fire smoke and nonsmoke sources across the contiguous U.S. We found that wildfire smoke has the most significant impact on air quality in the West Coast, followed by the Southeastern U.S. Between 2007 and 2018, fire smoke contributed over 25% of daily PM2.5 concentrations at ∼40% of all regulatory air monitors in the EPA's air quality system (AQS) for more than one month per year. People residing outside the vicinity of an EPA AQS monitor (defined by a 5 km radius) were subject to 36% more smoke impact days compared with those residing nearby. Lowering the national ambient air quality standard (NAAQS) for annual mean PM2.5 concentrations to between 9 and 10 μg/m3 would result in approximately 35-49% of the AQS monitors falling in nonattainment areas, taking into account the impact of fire smoke. If fire smoke contribution is excluded, this percentage would be reduced by 6 and 9%, demonstrating the significant negative impact of wildland fires on air quality.