Exposure to the mixtures of organic compounds in homes in Japan

The aim of the study reported herein was to characterize occupants' simultaneous exposure to mixtures of organic compounds in homes. Statistical distributions for concentrations of 28 organic compounds (17 VOCs and 11 aldehydes) measured in 1417 homes were generated to analyze concentration distributions. Three candidate distributions were identified for fitting the measured data: log-normal, exponential and gamma distributions. It appears from the results of fitting tests that gamma distributions are capable of representing 28 compound concentrations. Probability distributions show that formaldehyde and acetaldehyde ranged from 25 to 220 microg/m3 at 90% probabilities and most VOCs ranged from 3 to 80 microg/m3 at 90% probabilities. In order to characterize the occupant's exposure to the mixtures, the joint probability distributions of organic compounds were generated from the best-fitted distributions of individual compounds under the assumption that concentrations of organic compounds are mutually independent in homes. These joint distributions provided the statistical data for characterizing the occupant's exposure to the mixtures of organic compounds in homes.

Occupants often encounter not just one compound in indoor environments, but many compounds due to their concurrent emissions from several sources. This paper describes characteristics of statistical distributions for concentrations of 17 VOCs and 11 aldehydes in homes in Japan. After applying a probability model to the occupants' simultaneous exposure to mixtures of organic compounds, the authors interpret the current state of the occupant's exposure to the mixtures within homes using joint probability distributions of 28 organic compounds.