VOC testing and indoor air quality: what the numbers mean

Volatile organic compounds (VOCs) are emitted by several building materials, furnishings, adhesives, paints, and cleaning products. In a well-ventilated space, most VOCs disperse quickly. In a tightly sealed new build or a recently renovated room, they can accumulate to levels that cause irritation or, in some cases, longer-term health concerns. VOC testing is the way to find out what is actually present and at what concentration.

Common sources of indoor VOCs ¶

Formaldehyde is one of the most commonly elevated VOCs in indoor environments. It is emitted by composite wood products, insulation foam, and some textiles. Benzene, toluene, ethylbenzene, and xylene (collectively BTEX) are associated with paints, adhesives, and solvents. Limonene and alpha-pinene come from cleaning products and air fresheners and are generally lower concern, though they can react with ozone to form secondary pollutants.

New builds in Japan are increasingly airtight due to energy efficiency requirements, which means off-gassing from materials has less opportunity to disperse. Post-renovation testing is also common where occupants have reported symptoms that began after building work.

How passive sampling works ¶

Passive sampling uses a small diffusion tube or badge that absorbs VOCs from the air over a defined period, typically 48 to 72 hours. The sampler does not require power or a pump. You place it in the room, leave it for the sampling period, seal it, and return it to the lab. The lab then desorbs the collected compounds and analyses them by gas chromatography.

Lank CoreLab supplies sampling media by post. You deploy the sampler, return it in the pre-paid packaging, and we run the analysis. The report covers a panel of 30 VOCs plus PM2.5 and PM10 particulate fractions.

Interpreting the results ¶

VOC results are reported in micrograms per cubic metre. The World Health Organisation and Japan's Ministry of Health, Labour and Welfare publish guideline values for a number of individual compounds. For total VOC (TVOC), the commonly referenced threshold for indoor environments is 300 micrograms per cubic metre as a long-term average, though this is a guideline rather than a regulatory limit.

Where a result is above a guideline value, the report will identify the compound, its likely source category, and the ventilation or remediation measures most likely to reduce it. In most cases, increased ventilation is the first and most effective response.

The indoor air VOC and particulate assessment costs ¥21,000 and uses passive sampling media that we post to you. If you are dealing with a post-renovation concern or a workplace assessment, email us with a brief description of the space and we can advise on the sampling approach before you commit.