The Growing Threat of Wildfire Smoke
Canada is experiencing another dangerous wildfire season, with burning forests sending smoke plumes across provinces and into the United States. The pace of the 2025 fires is similar to the record-breaking 2023 wildfire season, which exposed millions of people in North America to hazardous smoke levels. This recurring issue highlights the urgent need for better monitoring and response strategies.
For most of the past decade, forecasters have used satellites to track these smoke plumes, but the data was limited to a two-dimensional view. Satellites could not determine how close the smoke was to Earth’s surface. The altitude of the smoke plays a crucial role in its impact on human health. If a plume is high in the atmosphere, it may not affect the air people breathe, as it floats overhead. However, when smoke plumes are close to the surface, people inhale harmful chemicals and tiny particles known as PM2.5. These particles can penetrate deep into the lungs and worsen asthma and other respiratory and cardiac conditions.
The Environmental Protection Agency uses a network of ground-based air quality monitors to issue alerts, but these monitors are few and far between, leading to broad estimates of air quality in many areas. Now, a new satellite-based method developed by researchers at universities and federal agencies over the past two years offers a more detailed understanding of smoke plumes.
Building a Nationwide Smoke Monitoring System
This innovative approach uses data from the Tropospheric Emissions: Monitoring of Pollution (TEMPO) satellite, launched by NASA in 2023. TEMPO allows scientists to determine the height of smoke plumes by analyzing how much oxygen molecules absorb sunlight at the 688 nanometer wavelength. Smoke plumes higher in the atmosphere reflect more solar radiation back to space, while those closer to the surface reflect less due to higher oxygen absorption.
Understanding this physics enabled scientists to develop algorithms that use TEMPO’s data to infer the altitude of smoke plumes and map their 3D movement in nearly real time. By combining TEMPO’s data with measurements of atmospheric particles from the Advanced Baseline Imager on NOAA’s GOES-R satellites, forecasters can better assess the health risks posed by smoke plumes almost in real time, provided there are no clouds obstructing the view.
This represents a significant advancement over ground-based air quality monitors, which can be hundreds of miles apart. For example, Iowa had about 50 air quality monitors reporting data on a recent day for a state covering 56,273 square miles, with most monitors clustered around major cities.
NOAA’s AerosolWatch tool currently provides near-real-time images of wildfire smoke from its GOES-R satellites, and the agency plans to integrate TEMPO’s height data. A prototype system called FireAQ, developed through a NASA-supported research project on fire and air quality, allows users to zoom in to the neighborhood level to see how high the smoke plume is. However, the prototype is only updated once a day, resulting in delayed data and limitations in providing smoke height information where clouds are present.
Rising Wildfire Health Risks
Fire risk is increasing across North America due to rising global temperatures and more people moving into wildland areas. While air quality in most of the U.S. improved between 2000 and 2020 thanks to stricter emissions regulations, wildfires have reversed this trend in parts of the western U.S. Research has shown that wildfire smoke has effectively erased nearly two decades of air quality progress in those regions.
Advances in smoke monitoring mark a new era in air quality forecasting, offering more accurate and timely information to protect public health against escalating wildfire threats. This development is critical as the frequency and intensity of wildfires continue to rise, posing growing challenges for communities and environmental agencies alike.