Air Monitoring Lessons from 2025: Charting the Year Ahead

As 2025 comes to a close, air quality monitoring sits at the intersection of shifting regulations, smoke-driven pollution events, and fast-growing sensor networks. Through all of it, the need for defensible, reference-grade data hasn't changed.

Several threads ran through the year: the American Lung Association documented how extreme heat and wildfire smoke had worsened air quality, the future of the federal PM2.5 standard became uncertain, and low-cost sensors kept expanding monitoring coverage at the neighborhood level. Here's what stood out, and what it means for 2026.

Smoke and Heat Shaped the Data

The American Lung Association's 2025 "State of the Air" report highlighted the factors that worsened air quality in 2023: extreme heat that pushed ozone higher in many central states, and an unprecedented blanket of smoke from wildfires in Canada that drove ozone and particle pollution higher in dozens of central and eastern states.[1] The report also notes that a changing climate is making it harder to protect decades of Clean Air Act progress.[1]

For monitoring programs, that's a reminder that pollution doesn't stop at a county line, and that regional and national networks matter as much as ever.

Sensors, Models, and the Reference Anchor

Low-cost sensors continued to expand coverage between regulatory stations. Their data still depends on correction against reference-grade monitors: peer-reviewed research identifies relative humidity as a primary source of error for widely used light-scattering sensors, and EPA developed a national correction model for one of the most common sensor types.[2] Newer correction approaches use machine learning,[3] but every one of them relies on the same thing: collocated, reference-grade data to learn from.

Regulatory Shifts and Defensible Data

The PM2.5 standard was the year's biggest regulatory story. EPA announced a reconsideration of the PM NAAQS in March 2025,[7] and in November 2025 asked the D.C. Circuit to vacate the 2024 rule that lowered the primary annual PM2.5 standard from 12.0 to 9.0 µg/m³.[8] Whatever the outcome, the takeaway for monitoring programs is the same: regulatory decisions rest on data, and that data has to hold up.

Tisch Environmental's high volume air samplers include US EPA Federal Reference Method configurations for TSP and PM10,[9] and the TE-Wilbur is an EPA-designated Federal Reference Method for PM2.5 and PM10.[10]

Public Engagement and Hyperlocal Data

Affordable sensors helped schools, community groups, and advocates track conditions closer to home. Looking into 2026, demand for hyperlocal data will likely keep growing, and so will the need to connect it to reference-grade measurements that give it context.

Final Thoughts: Looking to 2026

Air monitoring is moving toward more connected systems that combine reference monitors, sensor networks, and models. Collaboration between agencies, researchers, and industry will shape how well those pieces fit together. Tisch Environmental remains committed to building the reference-grade instruments those systems depend on.