What do the sensors measure?
The sensors measure
- the concentration of Particulate Matters (PM2,5) in the air
- the concentration of Volatile Organic Compounds (VOCs) in the air
- the air temperature
- the humidity in the air
Particulate Matters (PM2.5)
PM2.5 are air pollutants with a diameter of 2.5 microns (micrometers or µm) or less. They are also known as ‘fine particulate matter'. Common PM2.5 sources are car traffic, industrial plants, metal processing, cleaning fluids, beauty products, candles, cooking and smoking.
Volatile Organic Compounds (VOCs)
VOCs are different organic chemicals, that are emitted as gases from certain solids or liquids. They include both human-made and natural chemical compounds. A total VOC (tVOC) sensor detects such gases and summarizes them into one level. No individual gas is tracked. Both harmful and harmless VOCs are detected.
Examples of families of substances that the VOC sensor detects:
- Aldehydes (formaldehyde, acetaldehyde, acrolein).
- Hydrocarbons (toluene, benzene, undecane, xylene, naphthalene, butane, styrene, ethylbenzene, propane, kerosene).
- Amines (ammonia derivatives), alcohols (ethanol etc), ketones (acetone, methylethylketone (MEK), butanone, butanedione).
- Esters (butyl acetate).
- Carbon monoxide, hydrogen, acrylamide, organic acids.
Common VOCs sources are building materials (paint and varnish), furniture, printers, cleaning products, air fresheners, laundry detergent, glue, paint, perfume, repellent, scented candles etc.
People and animals also release VOCs when they breathe, perspire or digest. These VOCs are not dangerous for humans if the room is properly ventilated. The Blueair filters are not designed to remove these VOCs. You easily get rid of them if you open the windows every day for 5-10 minutes.
A high tVOC value may result from a high level from one single compound or it may be a collection of low compound levels from a chemical ‘mix’. Our filters remove most of the VOCs that the sensors detect, but not all of them. If you get high VOCs that don't go down with ventilation, investigate the potential source of pollution. Check your app to spot the moment when the VOCs started to increase. Then try to relate it to an event that occurred at that time (new furniture, use of a fireplace, cooking, big cleaning)? If you need help to understand the values, please contact the place where you bought the unit or Blueair directly.
Air temperature and humidity
The sensors detect water stagnation, water damages, humid surfaces and warm environments. These factors can encourage the growth of mold, bacteria and allergens, such as house dust mites. The common recommendation of humidity is between 30-65%. VOCs tend to evaporate more with a higher temperature.