Air Quality Benefits and Disbenefits of Forests under Future Environmental Stressors

Air quality in the U.S. has improved greatly in the past half century, due to environmental policies such as the Clean Air Act (CAA) focused on controlling anthropogenic point and mobile sources. As the contributions of anthropogenic sources decrease and environmental stressors, such as wildfire, increase, forests are becoming increasingly important diffuse sources and sinks of atmospheric compounds. Indeed, forests impact several air quality programs, yet stressors are modifying these forest-compound interactions. To characterize how forests may impact current and future air quality, we reviewed studies on environmental stressors affecting forest interactions with key air pollutants regulated under the CAA. Long-term temperature trends and changes in precipitation, as well as disturbances such as wildfire, pest outbreaks and drought are among the stressors considered. Overall, increasing stressors on forests are generally worsening air quality. Indeed, the increase in wildfire is one of the main contributors to current declines in air quality. Other effects were bidirectional or there were information gaps, especially in predicting multistressor impacts. Forests are fundamental to life and environmental stressors are shifting their impact on air quality. As a result, it is imperative to understand the benefits and disbenefits of forests to better predict and manage future air quality.

Impact/Purpose

This is a review of the scientific literature of how environmental stressors (e.g., wildfire, pest outbreaks, drought) can impact air quality through effects on forested landscapes. In doing this, we show that certain stressors, particularly wildfire, are increasingly impacting air quality through the release of air pollutants, such as particulate matter. The effects of other stressors are more bi-directional with increasing air pollution in some cases and decreasing in others. We also highlight the high degree of uncertainty from multiple stressors acting concurrently or sequentially. This work will inform other researchers regarding the current status of scientific findings and knowledge gaps of the field, while also be useful for air quality managers, since non-point sources of pollution are becoming relatively more important as many of these environmental stressors increase and point-sources decline. 

Citation

Lassiter, Meredith G., Rebecca M. Dalton, Nicole E. Olson, S. McDow, Jeffrey D. Herrick, AND Stephen D. LeDuc. Air Quality Benefits and Disbenefits of Forests under Future Environmental Stressors. American Chemical Society, Washington, DC, 3(2):262-278, (2026). [DOI: 10.1021/acsestair.5c00391]

DOI: Air Quality Benefits and Disbenefits of Forests under Future Environmental Stressors