Smoke and Air Quality

Background

Smoke from extreme wildfires in Canada adversely affected air quality in many regions in 2023^1,2.

Pathways to achieving net-zero and net-negative greenhouse-gas (GHG) emission targets rely on land-based contributions to carbon (C) sequestration. However, projections of future contributions neglect to consider ecosystems, climate change, legacy impacts of continental-scale fire exclusion, forest accretion and densification, and a century or more of management.

Background. Wildfire smoke events are increasing in frequency and intensity due to climate change. Children are especially vulnerable to health effects even at moderate smoke levels. However, it is unclear how parents respond to Air Quality Indices (AQIs) frequently used by agencies to communicate air pollution health risks. Methods.

Smoke from the Los Angeles (LA) wildfires that started on January 7, 2025 caused severe air quality impacts across the region. Government agencies released guidance on assessing personal risk, pointing to publicly available data platforms that present information from monitoring networks and smoke plume outlines.

Wildfires in the western US increasingly threaten infrastructure, air quality, and public health. Prescribed (“Rx”) fire is often proposed to mitigate future wildfires, but treatments remain limited, and few studies quantify their effectiveness on recent major wildfires.

RATIONALE Wildfires have increased in frequency and intensity due to climate change and now contribute to nearly half of the annual average of fine particulate matter in the US. While the effects of short-term wildfire-PM_2.5 exposure on respiratory diseases are well-described, the impact of climate change on longer duration wildfire-PM_2.5 mortality is unknown.

Climate change has increased forest fire extent in temperate and boreal North America.

Importance: A growing body of research suggests that exposure to fine particulate matter (PM_2.5; particle size 2.5 microns or smaller) may be associated with mental health outcomes. However, the potential impact of wildfire-specific PM_2.5 exposure on mental health remains underexplored.

Fire activities introduce hazardous impacts on the environment and public health by emitting various chemical species into the atmosphere. Most operational air quality forecast (AQF) models estimate smoke emissions based on the latest available satellite fire products, which may not represent real-time fire behaviors without considering fire spread.