Evaluation of formaldehyde emissions by school supplies using a low-cost passive sampler and spectrophotometric determination

This article presents the development and application of a low-cost passive monitor for indoor formaldehyde (CH2O) monitoring. The system is based on the diffusion sampling of formaldehyde and the pararosaniline reaction on a collection filter, followed by the elution and analysis of the product by spectrophotometry. The system was validated against a standard atmosphere of formaldehyde with 99% of collection efficiency. The device was applied in the assessment of formaldehyde emissions for school supplies (glitter glue, modeling clay, crayons, glue stick, felt pen, and plastic ink), in which the highest concentrations of formaldehyde were obtained for the felt-tip pen (approximately, 170 μg/g) and the lesser to glue stick (14 μg/g). The application of the passive sampler in a primary classroom environment demonstrated that relative high levels of formaldehyde can be measured in schools are usually considered to be linked to the high density of furniture in the classrooms, but it was also verified that school supplies can significantly contribute in the concentrations of formaldehyde indoor when associated to poor ventilation.