Formaldehyde measurements in residential indoor air using a developed sensor element in the Kanto area of Japan

We undertook this to determine the formaldehyde concentration in Japanese houses and the relationship between formaldehyde levels and the age and temperature of a house using a sensor element that we developed for time-integrated measurements of formaldehyde concentration in actual environments. We evaluated the correlation between the formaldehyde concentration estimated by the dinitrophenylhydrazine (DNPH)-derivatization method and that obtained with our sensor element. We found a linear relationship between the two results indicating that reliable measurements can be performed using the developed sensor element in actual environments. The indoor concentration of formaldehyde was determined in a study of 34 homes in the Kanto area of Japan, between September 28 and October 27, 2007. We obtained the highest formaldehyde concentrations of 92 ± 15 μg/m(3) for apartments 0-2 years after their renovation, and a simple linear relationship was found between formaldehyde concentration and the age of the apartment. We also found that the formaldehyde concentration in a room containing furniture increased by 10% when the temperature increased by 1°C.

This study contributed to the measurements of indoor formaldehyde levels. We have used a newly developed sensor for time-integrated measurements of formaldehyde concentrations. This sensor does not need a power supply during exposure to air, and does not need special skills to use. This research showed that homeowners successfully deployed the sensor at the desired place and desired period in their house by themselves. Formaldehyde is emitted by various off-gassing sources, such as furniture. Therefore, for example, homeowners may want to measure the change of formaldehyde levels in their house before and after installing new furniture. This sensor may also be deployed by occupants to reduce the cost of a large-scale exposure assessment study.