VOC

■VOC and the guideline value

Breathing in Volatile Organic Compounds (VOCs) for a long time may pose health hazards to humans, depending on inhaled amount of them. VOCs generated from construction materials, furniture, and household essentials are considered as the main causative substances of so-called "Sick building syndrome", a typical indoor health problems. In 2002, Ministry of Health, Labour and Welfare of Japan formulated the indoor air quality guideline with reference concentrations for 13 chemical substances. The guideline value is determined as "the concentration of a chemical substance which would not cause health damages to human even if a human breathes air containing contaminant of such concentration through the course of a lifetime".

■What is TVOC

Ministry of Health, Labour and Welfare of Japan defined the guideline value of VOC only for 13 substances. But other VOCs may also influence human health. However, there are too many kinds of VOCs to determine guideline values for all of them. Therefore, the sum total of concentrations of all VOCs including 13 substances is controlled as TVOC (Total Volatile Organic Compounds) in Japan. The provisional target value of TVOC is 400μg/m3.

■The guideline value of chemical substances in indoor air