How to avoid Volatile Organic Compounds

VOCs are organic chemicals which are emitted as gases or vapours into our homes. Some VOCs are more dangerous than others. When we talk about VOCs, we're usually talking about those produced by human activity and not those released by plants and natural phenomenons such as forest fires.

Used as part of the manufacturing process of many products and materials found around the home (including carpets, paint, laminate flooring, computers, solvents, textiles and deodorants), VOCs are emitted by products and contaminate indoor air as they are released. The most common VOC found around the home is formaldehyde.

Responsible for a range of diseases and health issues, the most harmful VOCs are classed as carcinogens and their use is strictly regulated. In terms of environmental harm, VOCs cause various types of pollution including the production of ozone which, in turn, contributes to the greenhouses gas effect. 

VOCs may have biogenic or anthropogenic sources, meaning they can occur naturally or be brought about by human activity.

They are chemical compounds containing at least one carbon atom (excluding carbon monoxide, carbon dioxide, carbonic acid, metallic carbides or carbonates) and one or more of the following elements: oxygen, hydrogen, nitrogen, phosphorus, sulphur, silica or halogen. VOCs have a high vapour pressure at room temperature meaning they are readily emitted into ambient air and found at their highest concentrations indoors.

The most common VOCs are:

• formaldehyde;

• benzene;

• acetone;

• ethanol;

• butane;

• styrene;

• tetrachloroethylene

• aldehyde.

Emitted by many common household materials and products, VOCs alter the chemical composition of ambient air and are considered pollutants.

Organic compounds are widely used in products as solvents, dissolvents, degreasers, preservatives, dispersants, cleaning agents, and so on. 

In the UK, the Industrial Emissions Directive (IED) is responsible for setting out provisions for VOCs within industrial processes. Around twenty sectors are monitored covering everything from footwear manufacture to dry cleaning. 

Annual emissions of non-methane volatile organic compounds have been measured in the UK since 1970. While this number decreases year after year, a total of 812 thousand tonnes was recorded in 2019 alone. 

The manufacturing industry is the second biggest contributor of VOCs right after petroleum and natural gas extraction, petrochemical activities and the burning of fossil fuels in industries, homes and transport. One of the largest contributions to VOC emissions is the use of solvents from both domestic products and industrial processes.

VOCs around the home

Among the most common VOCs is formaldehyde which can be emitted from a number of household sources: 

• paint;

• glue, varnish and stains;

• wallpaper;

• composite woods like chipboard, melamine-faced wood, decorative laminate, particleboard, MDF, and so on.  

• cleaning products;

• rugs, carpets, soft furnishings;

• candles, incense, room fresheners;

• cosmetics and synthetic clothing;

• toys, ornaments;

• cooking smoke and fumes;

• cigarette smoke, and so on.

Solvent-based paints have much higher VOC emissions than acrylic paints. The VOCs evaporate into the air both during application and while the paint is drying. As a general rule, velvet or satin-finish paints will contain more VOCs than those with a matt finish. Colourants also increase the amount of VOCs in a paint.

VOC content vs. emissions

The VOC content of paint is indicated in grams per litre (g/l). The Paint Product Directive (2004/42/CE) is enacted in the UK by the Volatile Organic Compounds in Paints, Varnishes and Vehicle Refinishing Products Regulations (2012 SI 2012 No 1715). These regulations set out a maximum level of TVOCs (Total Volatile Organic Compounds) allowed and the limits must absolutely be respected. TVOC emissions, the amount released in the air after application and during the drying process, are measured in µg/m³ (milligrams per cubic metre of air).

VOC content and emissions are therefore not the same thin and it is VOC emissions that determine the concentration of chemical compounds in indoor air.

VOC regulations 

The Volatile Organic Compounds in Paints, Varnishes and Vehicle Refinishing Products Regulations 2012 sets out the maximum level of VOCs allowed for each type of paint and varnish in grams per litre. In addition, you can look out for the VOC globe system.

Designed to increase consumer awareness of VOCs in the UK, the globe system rates VOC levels in paint from minimal (0-0,29%) to very high (over 50%). However, the label system is licensed and its use is not compulsory.

Maximum VOC levels in paints and varnishes

* Volatile Organic Compounds in Paints, Varnishes and Vehicle Refinishing Products Regulations 2012

It's also worth looking out for an EU ecolabel or labels like like 'non-toxic', 'eco-friendly' or 'natural' for greater reassurance.

What are the health impacts of VOCs? 

VOCs can have a direct and an indirect effect on human health:

• The indirect impact relates to the fact that VOCs release ozone precursor gases. Ozone pollution can have a variety of consequences on human health depending on the duration and level of exposure, and the volume inhaled. The health impacts will vary depending on the person exposed and their state of health. Some effects includes eye, nasal or throat irritation, chest discomfort, shortness of breath, cough, mucosal irritation, eczema, sleep disturbance, and so on. 

• The direct impact relates to the serious consequences of being exposed to high concentrations of VOCs over an extended period of time. Some of the most harmful VOCs include benzene, formaldehyde, dichloromethane, perchlorethylene (or tetrachlorethylene), xylene, toluene, acetaldehyde. These VOCs are subject to strict regulations and it is essential to wear adequate protection when dealing with them.

VOC classifications: International Agency for Research on Cancer

The International Agency for Research on Cancer categorises VOCs according to their toxicity.

• Group 1: known human carcinogens (formaldehyde, benzene).

• Group 2A: probable human carcinogens (tetrachloroethylene, styrene).

• Group 2B: possible human carcinogens (acetaldehyde, dichlorobenzene).

• Group 3: Unclassifiable as to carcinogenicity in humans.

• Group 4: Probably not carcinogenic to humans.

* See the International Agency for Research on Cancer for full details

Environmental impacts of VOCs 

From an environmental standpoint, VOCs are responsible for a range of different types of pollution including photochemical smog and tropospheric ozone. As mentioned above, VOCs are ozone precursors. Ozone causes considerable damage to plants (reduced resistance to disease, lower crop yields, etc.), enhances the greenhouse effect and interferes with photosynthesis. 

On the global scale, for every 20 million tons of solvents used, around three quarters will disappear through evaporation. In marine environments, only a small amount of VOCs are dissolved in water with the majority resting on the surface. Hydrocarbon aromatics do not readily break down and are toxic to marine life.

As seen above Volatile Organic Compounds are more or less everywhere. And it'll come as no surprise to hear that the VOC concentrations indoors are, on average, eight times higher than outdoors. 

In order to lower VOC levels and protect your health, you should limit the use of VOC-emitting products. Failing that, choose products with low or minimal VOC concentrations. Here are a few habits you can form around the home:

• limit the use of incense, scented candles and room fragrances;

• choose natural wood over composite woods like plywood or melamine-faced wood; 

• reduce the amount of chemical cleaners you use and replace them with natural or organic cleaning products;

• opt for natural textiles and materials;

• look out for minimal or low VOC paints;

• after unpacking a new product (such as a sofa, furniture, etc.), allow the item to air out outdoors before bringing it indoors; 

• air out your home several times a day (twice a day for 10 minutes minimum).

It's also possible to purify the air of your home using an air purifier. If you are really determined to keep an eye on VOC pollution, you can invest in a handheld VOC detector such as a photoionisation detector (or PID).