ISO Developed New Air Cleaning Classification System
A new international standard provides a way to evaluate air filtration devices against common indoor pollutants.
Updated on Sept. 23, 2026 in Asthma
The International Organization for Standardization has released a new classification system for air cleaning devices used in general ventilation. This tool helps assess performance against specific molecular contaminants in indoor spaces.
Why it matters
The standard provides a clear method for evaluating how well air cleaning systems manage molecular contamination in buildings with air recirculation. This classification aims to help users better understand device capabilities for maintaining indoor air quality.
The new ISO/AWI 10121-4 standard establishes a framework for classifying gas-phase air cleaning devices by testing them against three primary reference pollutants. The system assigns devices into one of three duty levels to define their performance capacity for molecular contamination.
The players
International Organization for Standardization
An international body that develops and publishes voluntary technical standards across various industries to improve global safety and quality.
The details
The classification system functions by testing filtration devices against ozone, nitrogen dioxide, and toluene to determine their efficacy in removing molecular air pollutants. The standard also allows for optional testing against formaldehyde and isopropanol to provide a broader performance profile. By assigning devices to one of three duty levels, the system aims to standardize how performance ranges are communicated for indoor ventilation applications.
Timeline
September 23, 2026: The ISO published the standard document.
Health Landscape
This development integrates with the existing ISO 10121 series to provide a more comprehensive approach to gas-phase air cleaning in buildings. It marks an evolution in how indoor air treatment performance is benchmarked globally.
While this standard is designed for manufacturers and building managers, it establishes a clearer benchmark for indoor air quality technology. If you are concerned about building air filtration, it is worth discussing the facility's air quality standards with property managers.
The takeaway
The new ISO standard offers a structured way to measure how effectively air cleaning systems remove specific pollutants like ozone and nitrogen dioxide. Readers can monitor for industry adoption of this classification to better understand the performance specifications of their indoor environments.
Further reading
For more information on managing indoor environments, visit Asthma.
More information
Review the technical details of the new classification system on the ISO standard documentation page.
Source note: This article includes information reported by ISO.
