Global Modeling Assessment of PM2.5 During Wildfires: Inferring the Impact of PM2.5 Exposure on Adverse Respiratory & Cardiovascular Conditions

Particulate matter pollution is a mixture of solid and liquid droplets floating in the air that can lead to reduced air quality and increased adverse health impact. Fine particulate matter (PM_2.5) can be emitted into the air from anthropogenic sources such as the burning of fossil fuels, motor vehicles, and powerplant emissions. Exposure to PM_2.5 can aggravate pre-existing respiratory and cardiovascular conditions. When PM_2.5 is inhaled it can cause damage to the lungs such as reduced lung function and shortness of breath. After being inhaled PM_2.5 can enter the bloodstream and cause harm to the heart. One major natural source of PM_2.5 exposure is from wildfire smoke. The particulates within the smoke from the wildfires can spread from the initial source region, potentially impacting communities both near and far. During and after wildfire events, PM_2.5 levels can exceed the WHO air quality guidelines (10 annual mean; 25 daily mean), becoming hazardous to an individual's health.

Global models can be used to simulate the emission and transport of these particulates and subsequently they can be valuable to air quality forecasting in highly polluted areas. The NASA Goddard Earth Observing System (GEOS) Composition Forecast (GEOS-CF) system has been used to produce near-real time air quality forecasts of atmospheric composition at a high global resolution of 25x25 km². The GEOS-CF system utilizes the GEOS weather forecast model coupled with GEOS-Chem (version 11) chemistry module to provide analyses and forecasts of various toxic air pollutants, including PM_2.5. The GEOS-CF simulated high levels of PM_2.5 (40 to 250 ), exceeding the WHO guidelines, during multiple recent regional and global wildfire seasons, including the 2017 Washington State and Northern and Southern California wildfire seasons. Furthermore, the GEOS-CF simulated PM_2.5 applied to a human health assessment model, BenMAP (The Environmental Benefits Mapping and Analysis Program, version 1.3), estimates the impact on adverse respiratory health conditions due to PM_2.5 exposure from wildfires. The GEOS-CF predicted PM_2.5 during the wildfire season with the corresponding BenMAP results provides an assessment of the human health impact of PM_2.5 exposure.