Benzene: invisible and harmful pollution of indoor air


Indoor air quality is often degraded by contamination with aromatic Volatile Organic Compounds (VOCs) such as benzene. This gaseous pollutant is one of the most dangerous VOCs and is present in a large proportion of homes and offices.

As we spend most of our time indoors, avoiding exposure to toxic pollutants should be a major concern for everyone, especially pregnant women and young children.

Benzene and hydrocarbons in indoor air come from multiple sources of contamination.

When to look for benzene pollution?

Benzene and hydrocarbons are naturally contained in petroleum products such as gasoline and are released by car and truck traffic. Since outdoor air is the foundation of indoor air, a major road network in the vicinity of a home or an office induces indoor air pollution.

Having a garage that communicates with the inside of your home also produces significant indoor air pollution from benzene through the evaporation of gasoline as well as when starting the vehicle. The same applies to all equipment running internal combustion engines. The fumes from a fuel tank can also diffuse toxic hydrocarbons throughout the house.

Hydrocarbon indoor pollution  pollution can also be linked to soil pollution at the location where the building was built. This soil contamination is generally long-lasting. Because they are volatile, benzene and hydrocarbons are slowly extracted from the ground and continuously diffuse into the building's indoor air.

The combustion of organic materials such as wood also produces benzene. A chimney or wood stove can be a significant source of indoor air pollution from benzene. The combustion of candles (fragrant or unscented), incense and tobacco generates significant amounts of benzene and formaldehyde in indoor air.

Despite its recognized toxicity and even though its use is nowadays more limited, benzene continues to be used in many chemical industries and regulations concerning this substance are different from one country to another.

Even at low doses, benzene vapors are very toxic.

What are the health effects of benzene?

Benzene is a substance classified as carcinogenic to humans (Category 1) by the World Health Organization (WHO), with the development of leukemia (cancer of the blood system) in particular. Data in the literature show that it acts without a threshold and that any exposure to this aromatic compound should be avoided.

Its presence in indoor air is the main source of human exposure and must be controlled to limit health risks. For this reason, WHO recommends that a concentration of 1.7 µg/m3 in the air you breathe should not be exceeded. Exposure to this rate over a lifetime corresponds to one in 100,000 chances of developing cancer. ANSES, the French Health Security Agency, has confirmed this value and defined the threshold of good indoor air quality at 2 µg/m3 (Indoor Air Guide Value) and a rapid alert and action value at 10 µg/m3.

Connected sensors cannot detect indoor air pollution by benzene

How to detect benzene pollution?

Knowing the indoor air quality of your home or office is now accessible to as many people as possible.
The connected indoor air quality sensors available on the market cannot detect indoor air pollution by benzene, only a laboratory analysis can obtain a specific response to this pollutant and with a level of sensitivity compatible with the values recommended by the health authorities.

Indoor air pollution by benzene can be limited with simple actions

What to do in case of benzene pollution?

The presence of benzene in indoor air is not inevitable and it is in most cases possible to improve indoor air quality in order to limit exposure to this most important pollutant.

The first thing to do is to have fresh air supplied to dilute the pollution. If the source of pollution by benzene and hydrocarbons is outside, it is necessary to choose to aerate at the time when car traffic is at its lowest. This involves creating a draft in the home or office twice a day for at least 10 minutes.

Then, it is important to identify the pollution of your indoor environment to eliminate and reduce benzene sources. The main situations that lead to indoor air pollution by benzene have been described at the beginning of this article. The following solutions can be considered:

- Limit the storage of gasoline and hydrocarbons

- Ventilate the garage and isolate it from the rest of the house

- Check the tightness of the heating oil tank and ventilate the storage area

- Check the exhaust ducts of chimneys, stoves and boilers

- Control soil contamination

- Limit the use of candles, incense

- Do not smoke indoors


Finally, treating indoor air with an air purifier is a solution to remove benzene from indoor air. This pollutant is a VOC and only air filtration with activated carbon can capture this toxic gas. The indoor air purifier will therefore necessarily have to integrate this type of technology. The efficiency of air purifiers varies from one brand and one model to another. In addition, it will be necessary to change the activated carbon filters regularly in order to maintain optimal efficiency.


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