The Global Open Air Quality Standards (GO AQS) working group convened to discuss the establishment of standards for formaldehyde, building upon previous discussions on particulate matter, carbon dioxide, carbon monoxide, and ozone.

Reconsidering Space Adaptability and Target Limits

The discussion began with the concept of “space adaptability,” a feature within GO AQS that links average pollutant limits to different indoor environments. While the community previously agreed with this approach in a survey, some comments suggested moving towards target limits instead of numerous environment-specific values. The concern was that multiple numbers could confuse the public and even companies manufacturing air quality instruments. The working group reviewed existing formaldehyde standards, noting the presence of short-term exposure limits (as low as 15 or 30 minutes) in some regulations, which are not currently reflected in GO AQS’s proposed limits (yearly, 24-hour, 8-hour, and 1-hour means). The proposed GOAQS limits are 10 μg/m³ (year), 20 μg/m³ (24 hours), 30 μg/m³ (8 hours), and 80 μg/m³ (1 hour).

Distinguishing Occupational vs. General Exposure

A member raised the important distinction between work exposure to formaldehyde, which is often regulated with short-term, high-limit exposure guidelines (e.g., in hospitals), and the chronic exposure in residential or office spaces. It was clarified that the current focus of GO AQS is on the latter – the exposure of general occupants, employees in offices, students, and hospital patients (not workers). Occupational exposure standards fall under the purview of specific governmental bodies, and GO AQS aims to avoid overlap at this stage.

Global Awareness and Regulatory Disparities

The discussion highlighted significant regional differences in awareness and regulation of formaldehyde. It was noted that the problem might be more severe and the awareness higher in Asia compared to Europe. This is partly attributed to stricter regulations on building materials and furniture in Europe. However, even in Europe, concerns were raised that while individual products might meet regulations, the cumulative effect of multiple items in an enclosed space could lead to elevated formaldehyde levels, and the public may not be fully aware of this risk.

Addressing Formaldehyde Sources and Mitigation

The presence of formaldehyde in unexpected products like cosmetics (especially in regions outside Europe, such as China and the US) was also mentioned as a concern. Testing in China revealed that new cars, even from reputable brands, often exceed WHO formaldehyde requirements significantly. This issue is also prevalent in North America and Canada, where new buildings using wood and glues can release high levels of formaldehyde initially. Ventilation and allowing new spaces (buildings and cars) to air out “Flushing” were suggested as effective mitigation strategies to reduce initial formaldehyde exposure. The “new” smell often associated with new products is frequently a combination of unhealthy chemical emissions.

Standardizing Units of Measurement

A key discussion point revolved around the unit of measurement for formaldehyde. While WHO currently communicates in micrograms per cubic meter, instruments often measure gases in parts per billion (ppb) or parts per million (ppm) depending on the concentration. The group considered whether adopting a common unit like ppb or ppm would be beneficial for sensor manufacturers and public understanding, provided clear explanations and standardized conversion tools. Concerns were raised about inconsistencies in online conversions due to factors like temperature, pressure, and the precision of molecular weights used. It was suggested that GO AQS could provide standardized conversion methods based on standard temperature and pressure (e.g., 25°C and 1 atmospheric pressure) and offer examples for common values to aid public comprehension. The importance of avoiding confusion when comparing measurements reported in different units was emphasized as crucial for accurate interpretation of air quality data. Sensor manufacturers already provide conversions in their platforms, highlighting the feasibility of this approach.

Towards a Single Limit for Better Communication

Echoing the initial point about target limits, a policy perspective suggested that communicating a single limit per pollutant might be easier for the public than managing multiple values for different environments. This aligns with the idea of moving away from the space adaptability feature for formaldehyde, at least in terms of public-facing standards.

Tentative Conclusion: A Threshold Ceiling Limit

Based on the discussion, the working group leaned towards not adopting the space adaptability feature for formaldehyde. Instead, there was support for establishing a threshold ceiling limit, likely the lowest achievable value, to be included within the GO AQS framework. This approach aims for simplicity and clarity in communicating formaldehyde standards to the public.

Next Steps

Following the initial discussions and data gathering on formaldehyde limits, the next crucial step involves soliciting further input from the working group members. To this end, an additional targeted survey will be distributed shortly. This survey is specifically designed to gather expert opinions and insights necessary to establish a definitive limit for formaldehyde within the GO AQS. The responses received will be instrumental in setting a protective and achievable standard for this pollutant.

• Recording: Formaldehyde WG – 2025 April 02