NIST‑Backed Standard Enables Measurement of Air Cleaner By‑Products

USA: NIST‑Backed Standard Enables Measurement of Air Cleaner By‑Products

A new test method developed by the National Institute of Standards and Technology (NIST) provides a consistent way to measure ozone, formaldehyde and ultrafine particles emitted by portable air cleaners, according to a release on September 2, 2025.

Rising Demand and Emerging Concerns

Following the COVID‑19 pandemic and an increase in wildfires, consumer demand for air‑cleaning devices surged, prompting manufacturers to broaden their product lines for single‑room use.

How Certain Technologies Generate By‑Products

While many devices rely on fibrous filters that capture particles, others employ ultraviolet light, ionization or catalytic reactions to neutralize pollutants. Those active processes can unintentionally create secondary chemicals such as ozone, formaldehyde or ultrafine particles.

The New ASTM Test Method

The procedure runs an air cleaner for four hours in a sealed chamber containing known reference chemicals. Samples are then analyzed: ozone and formaldehyde concentrations are determined by ultraviolet‑absorption spectroscopy, and ultrafine particles are quantified using scanning mobility particle sizing after charging the particles in an X‑ray field and enlarging them with a steam bath for laser‑scattering detection.

Implications for Industry and Consumers

Standardized measurements allow manufacturers to benchmark performance, improve designs, and potentially meet future emission limits, while giving consumers comparable data for informed purchasing decisions.

Collaboration and Standard‑Setting

The method, published by ASTM International, reflects a four‑year research effort by NIST and input from air‑quality scientists, manufacturers, testing laboratories and the public, creating a consensus standard intended to be fair and trustworthy.

Expert Outlook

“I’m excited that it’s finally coming out and will start impacting the world,” said Dustin Poppendieck, an indoor‑air‑quality researcher at NIST. “Now that these by‑products can be reliably measured, we can be more confident that air cleaners are beneficial to the air we breathe.”

This report is based on information from NIST, licensed under Public Domain (U.S. Government Work). Source: Official U.S. Government release.