Indoor air quality measurements of formaldehyde using low cost sensors

Formaldehyde is a significant health risk, and International Agency for Research on Cancer (IARC) classifies formaldehyde as a human carcinogen. There are stringent formaldehyde exposure guidelines that exist for indoor air (80 ppb WHO) that can be even lower at the national level (e.g., France 8 ppb by 2023). People are exposed to formaldehyde from a variety of sources inside their homes. These include many everyday products, such as cosmetics, furniture, and detergents. With the growing health threat that formaldehyde poses, it is becoming more critical to monitor homes and other indoor spaces so that inhabitants can take action to minimise their exposure.

Formaldehyde is usually measured by on-site batch sampling and off-site quantification in an external analytical laboratory. These procedures are expensive, time-consuming, require skilled personnel and do not allow on-site monitoring. Formaldehyde measurement in ambient air requires ppb-level detection sensitivity from a monitor. Furthermore, when used in indoor air monitoring, they must be selective to detect ppb-level formaldehyde concentrations in ambient air containing hundreds of compounds. Current products on the market require consumers to sacrifice sensitivity and selectivity for cost; low-cost sensors do not meet the goal of a low detection limit of 20ppb or give false positives to common chemicals such as ethanol.

Applied Nanodetectors indoor air quality monitoring system (AND-IAQ01), can detect formaldehyde at ppb levels. It also measures key indoor pollutants, including carbon dioxide, particulate matter (PM2.5), and total volatile organic compounds (TVOC). This device complies with the essential requirements of all relevant harmonised and designated standards required for The UKCA (UK Conformity Assessed) marking. The product is commercially available via key specialist suppliers.

The London Government Chemist (LGC) will evaluate our system performance by exposing the device to synthetic air/formaldehyde mixtures (down to 20 ppb) and evaluate the effect of confounding gases.