HCHO is the chemical formula for formaldehyde, which is a volatile organic compound (VOC) that can pollute indoor air. Formaldehyde is one of the many substances that make up total VOCs (TVOC) . It is a hazardous air pollutant (HAP) and a known carcinogen. Formaldehyde can be found in building materials, household products, and the use of un-vented, fuel-burning appliances, like gas stoves.

Formaldehyde can be measured using a special device or measuring instrument, such as a formaldehyde meter. A measurement like that is called a multifunctional air quality measurement where a few substances such as fine dust and total VOC gets measured. You can buy or rent a formaldehyde meter if you want to measure it yourself, or you can also let a professional company come over to do the measurement for you.

The concentration of formaldehyde in indoor air can be reduced by using a good air purifier, which can clean the air up to 99% from bacteria. The WHO guidelines for indoor air quality recommend a maximum exposure limit of 0.1 ppm (parts per million) for formaldehyde.

In summary, HCHO air quality refers to the concentration of formaldehyde in indoor air, which can be measured using a formaldehyde meter. Formaldehyde is a hazardous air pollutant and a known carcinogen that can be found in building materials, household products, and un-vented, fuel-burning appliances. The concentration of formaldehyde in indoor air can be reduced by using an air purifier.