Measurements of formaldehyde emissions in indoor environments using a colorimetric Passive Flux Sampler

Abstract

Formaldehyde (HCHO) is one of the most abundant volatile organic compounds in indoor environments. This pollutant exhibits concentrations that are several times higher than outdoor, rising questions about potential health effects from indoor exposure. Since building and furnishing materials are known to be important sources of formaldehyde, an efficient reduction of indoor concentrations could be achieved by replacing these emitters with less emissive materials. However, measurement techniques available to monitor in-situ emissions are either too cumbersome or require a delayed analysis in the laboratory, and therefore it is not an easy task to quickly identify sources of emissions. There is a need for real-time and easy-to-use analytical tools to pinpoint the strongest sources in indoor environments. In this communication, we will describe a Passive Flux Sampler (PFS) that is suitable for in-situ and real-time measurements of formaldehyde emissions from building and furnishing materials. This PFS is made of a small exposition cell containing a nanoporous sol-gel matrix doped with Fluoral-P. When exposed for a few hours onto an emissive material, Fluoral-P selectively reacts with formaldehyde, resulting in a color change of the matrix. An appropriate detector is then used to measure the matrix optical density, which is converted into an emission rate. This PFS was calibrated using building materials whose formaldehyde emissions were measured using an emission test chamber under normalized conditions (ISO 16000-9). We will also present the first deployment of this PFS in indoor environments and its potential for a robust identification of formaldehyde emission sources.