NASA’s TEMPO satellite enables better monitoring of bad air days

Wildfire smoke prompted hazardous air conditions in New York City and other urban centers across the United States in July 2026. NASA’s TEMPO satellite enables better monitoring of bad air days From 22,000 miles above, the new instrument lets researchers and regulators track airborne health threats in near real time, on a continental scale In early August the skies above Portland, Oregon, took on an increasingly familiar sepia tint, as easterly winds wafted plumes of gas and smoke from wildfires into the air over the city. At one point Portland’s air quality was rankedworst in the world, leading to the closure of summer camps and public pools and the cancellation of outdoor concerts.

In a summer of intense heat and wildfires, similar scenarios played out in cities across North America — New York, Denver, Chicago, Toledo. Above it all, a NASA satellite recorded the dynamic swirl of gases and particulates fueling these air quality crises. From a vantage point 22,000 miles above the equator, the Tropospheric Emissions: Monitoring of Pollution (TEMPO) satellite has provided near-real-time hourly snapshots of pollutants originating, migrating and dissipating in the daytime atmosphere over North America since September 2025.

Whereas previous pollution-monitoring satellites offered only one or two daily snapshots of air quality, this ongoing, continent-scale picture has helped researchers and regulators better understand and respond to some of the most unpredictable and uncontrollable pollutants in the atmosphere. TEMPO reveals how pollution — like the weather — is not stagnant. Visitors to the TEMPO Lite website can search for air quality data from all over the nation.

Since the 1970 passage of the Clean Air Act, the United States has made tremendous progress reducing the levels of six common hazardous air pollutants that people breathe. But progress in reducing two pollutants in particular — ozone and particulates smaller than 2.5 micrometers in diameter, or PM2.5 — has stalled over the past 15 years or so. Both are secondary pollutants, formed through chemical reactions in the atmosphere that are influenced by sunlight, heat and other variables.

With their complex chemistry and the fact that their precursors come from diffuse sources such as airports, agriculture and wildfires, secondary pollutants have been especially difficult to understand and control. They remain major contributors to the estimated 100,000 premature deaths, 10,000 premature births and 200,000 cases of child-onset asthma that are still caused by air pollution in the United States. And as a 2023 paper in the _Annual Review of Pharmacology and Toxicology_ concluded, there is growing evidence that air pollution may contribute to neurodevelopmental diseases such as schizophrenia as well as neurodegenerative diseases such as Alzheimer’s and Parkinson’s.

Firenadoes and drifting embers: The secrets of extreme wildfires TEMPO’s ability to track how secondary pollutants form over the course of a day has wide-ranging potential to help reduce those figures. State and local governments can use TEMPO to identify and mitigate precursors, which helps them better comply with federal air quality standards. Scientists can create forecast models for secondary pollutants and issue timelier warnings of dangerous air quality.