Formaldehyde odor and its interaction with the air of a sick building

Abstract

Apparently the most typical effects of formaldehyde on humans in a nonindustrial indoor environment are the sensory reactions. This paper reports on the absolute odor threshold and the perceived odor strength of formaldehyde as well as on the interaction effects between formaldehyde and the indoor air of a “sick building” (a detached preschool). The absolute odor threshold of formaldehyde was determined by a modified method of limits with forced choice responses. The odor strength of formaldehyde and the mixtures of formaldehyde and the indoor air was determined by magnitude estimation according to a master scale principle, using pyridine as master stimuli. The individual odor thresholds for formaldehyde were shown to range over two powers of ten and the distribution to be extremely positively skewed. The median value of the individual odor thresholds (ED 50s) was 0.06 mg/m 3 (0.05 ppm). The psychophysical relationship for formaldehyde odor strength is a power function (exponent = 0.76). the results from mixing formaldehyde with indoor air is mainly a relative increase in the perceived odor strength of the stimulus mixture at low concentrations while the perceived odor strength at high concentrations remains largely unchanged.