What is VOC (Volatile Organic Compounds) and Why it Matters?

Every breath we take contains more than just oxygen. Hidden in the air around us are invisible chemicals known as volatile organic compounds (VOCs). They come from everyday products—paints, cleaners, furniture, even cosmetics—and while they often go unnoticed, their impact on our health and the environment is significant. Understanding what VOCs are and why they matter is the first step toward making safer choices for cleaner air and healthier living.

Definition and characteristics of VOCs

Volatile organic compounds (VOCs) are organic chemicals that have a high vapor pressure and low boiling points at room temperature, which means they evaporate easily. They can be released as gases from certain solids or liquids, so you’ll find them off-gassing from paints, cleaners, fuels and other everyday products.

Many VOCs are man-made and used in manufacturing and consumer goods – for example, solvents in paints and industrial cleaners, ingredients in some pharmaceuticals, and certain refrigerants. Common examples include industrial solvents such as trichloroethylene, the fuel additive methyl tert‑butyl ether (MTBE), and chloroform which can form as a byproduct during water treatment.

VOCs cover a wide range of chemicals, some of which cause short-term health effects, while others can produce problems after long-term exposure, so they’re worth paying attention to.

Sources of VOCs

Volatile organic compounds (VOCs) come from many sources. Some are natural, while others are human-made. They’re released both indoors and outdoors.

Natural emissions

Biogenic volatile organic compounds (BVOCs) are airborne molecules released by plants, animals and microorganisms. The most common groups among them are terpenoids, alcohols and carbonyl compounds. Plants produce many of these VOCs as secondary metabolites; they help fend off herbivores, send chemical signals, attract pollinators and shape the exchanges between the biosphere and the atmosphere.

When plants emit VOCs during leafy, vegetative growth, we call those emissions green leaf volatiles (GLVs). On a global scale, the amount of carbon released in the form of VOCs is staggering—about 1,150 teragrams of carbon each year. Most of that comes from biogenic sources, with plants being the main contributors. Coniferous forests are especially strong sources of terpenes. Among all plant-emitted VOCs, isoprene stands out as the single most abundant.

Human-made emissions

Anthropogenic volatile organic compounds (VOCs) are organic chemicals produced by human activities. On the whole, humans emit some 142 teragrams of carbon per year as VOCs. But where exactly do these emissions come from? A large share is the result of incomplete combustion of fossil fuels. Ethane, for example, is the most widespread anthropogenic VOC.

But everyday products contribute as well. The solvents in paints, coatings, inks, adhesives and cleaning agents all release VOCs. Many aerosol sprays use butane and propane as propellants, and those gases are VOCs too. Burning or evaporating biofuels – for example bioethanol or used cooking oils – also releases VOCs. Finally, biomass burning, especially fires in rainforests, represents a major source of VOC emissions.

Indoor sources

Many common household items give off VOCs, which is why you can find indoor VOCs in everything from personal-care products to cooking fumes and cleaning sprays.

These indoor emissions include a range of chemicals – long-chain aldehydes, alkanes, terpenes, alcohols and esters are all commonly detected. New homes often show especially high levels because building materials, fixtures and surface coatings continue to off‑gas after installation.

Adhesives, sealants and paints are key culprits in newly built or renovated spaces. Pressed-wood products such as MDF and particleboard also release formaldehyde over time.

Tobacco smoke is a major source too: it contains roughly 7,350 chemical compounds, many of which are VOCs. Household cleaners and disinfectants add more VOCs to indoor air, and clothes cleaned with perchloroethylene or other dry‑cleaning solvents can slowly release vapors after you bring them home.

Don’t forget attached garages – fuels stored there can seep into living spaces and raise indoor VOC levels.

Outdoor sources

Outdoor VOCs come from a complex blend of natural and human-made sources. The most common human-related sources are vehicle exhaust, industrial emissions and wood burning. Oil and gas extraction and processing also release substantial amounts of VOCs.

Levels are generally higher in cities and industrial zones than in rural areas. At the same time, the biogenic emissions from plants can be a major contributor to outdoor VOCs. For more detail on industrial and combustion sources, see the Human-made emissions section below.

VOCs in everyday products

Volatile organic compounds (VOCs) are common in hundreds of household and personal-care products. You’ll find them in:

• Paints, varnishes, sealants and adhesives – as well as paint removers, organic solvents and aerosol sprays.

• Air fresheners, cleaning products, disinfectants, moth repellents, cosmetics and deodorants.

• Soft furnishings and building materials – carpets, vinyl floors, engineered wood, upholstery, foam – which can give off VOCs over time.

• Other sources inside your home include tobacco smoke, dry‑cleaned clothing and office equipment such as copiers.

• Fuel-related sources such as heating oil, gasoline and stored fuels, cooking, wood burning and various hobbies can add VOCs to the indoor air.

• Many DIY and hobby supplies – for example, some glues and permanent markers – can be sources too.

VOC concentration indoors vs outdoors

Many volatile organic compounds (VOCs) are consistently higher indoors—sometimes as much as ten times the levels measured outside. That means people who spend their time inside can be exposed to greater VOC concentrations than they would be in the great outdoors. But why?

It’s because indoor air often contains numerous emission sources and ventilation is limited, so pollutants tend to accumulate rather than disperse.

Health effects of VOC exposure

Exposure to VOCs can cause a variety of health problems. What happens depends on the specific chemical, how much you’re exposed to, and how long the exposure lasts.

Short-term health impacts

Volatile organic compounds (VOCs) can quickly irritate your eyes, nose and throat. They can cause headaches, nausea and a loss of coordination. At higher concentrations, people may experience dizziness, unusual tiredness or have trouble breathing. Some VOCs can also trigger allergic skin reactions. When VOCs build up in indoor air, they can make asthma symptoms worse.

Long-term health risks

Long-term exposure to VOCs can damage your liver, kidneys, and central nervous system. Some VOCs – benzene, for example – are known human carcinogens, while experts consider formaldehyde a probable human carcinogen. Chronic exposure to VOCs may also increase your risk of respiratory and cardiovascular disease.

In addition, certain VOCs can:

• Sensitize your skin

• Harm your reproductive health

• Damage specific organs

• Cause cancer or genetic mutations

• Disrupt your endocrine system

Vulnerable groups and higher risk populations

Who is most at risk from volatile organic compounds? A few groups stand out.

• Infants and young children: Their lungs and immune systems are still developing, making them more vulnerable. Their breathing patterns and behaviors also mean they inhale proportionally more air – and pollutants – than adults.

• Older adults: Especially those living in care homes, who may face higher VOC exposure from cleaning and disinfecting products. Chronic conditions and reduced resilience can make it harder to tolerate these exposures.

• People with existing respiratory conditions: Those with asthma or other lung diseases are more sensitive to irritants in VOCs, which can trigger symptoms or worsen breathing problems, even at low levels.

• Certain workers: Staff in cleaning, hospitality, and retail often use scented products, disinfectants, and other chemicals that can increase workplace exposure.

Environmental impact of VOCs

Volatile organic compounds (VOCs) pose a clear threat to the environment: not only do they worsen air pollution, but they can also contaminate water and soil.

Ozone and smog formation

Volatile organic compounds, or VOCs, are the main precursors of ground-level (tropospheric) ozone, which is the principal component of smog. Ozone forms when VOCs react with nitrogen oxides (NOx) in sunlight, through photochemical reactions.

High levels of ground-level ozone damage plants and crops and can disrupt entire ecosystems. Photochemical smog also cuts visibility and can lead to respiratory and other health problems in people.

Water and soil contamination

When volatile organic compounds (VOCs) leak, are spilled, or are disposed of improperly, they can pollute groundwater and surface water. Common culprits include industrial solvents and gasoline components.

This kind of pollution is particularly concerning because many communities rely on groundwater for their drinking water. When those sources become tainted, it puts public health and vital water supplies at risk.

Additionally, VOCs in soil can evaporate and migrate into buildings – a phenomenon called vapor intrusion – contaminating indoor air. In other words, these chemicals can compromise the quality of both the water we drink and the air inside our homes and workplaces.

Regulations and classifications of VOCs

Governments worldwide regulate volatile organic compounds (VOCs) to limit emissions and reduce health and environmental risks. However, specific rules differ by country – and even by region – so requirements can vary widely. If you work with VOCs, it’s crucial to check local regulations to understand what applies in your area.

United States

In the United States, VOC regulation is overseen by the Environmental Protection Agency (EPA) under the Clean Air Act. The EPA’s rules define a VOC as “any organic compound that participates in atmospheric photochemical reactions,” with an exception for substances the EPA has specifically excluded due to negligible photochemical reactivity.

The EPA sets national VOC emission standards for consumer and commercial products (40 CFR part 59) that limit the VOC content of items like paints, adhesives, and cleaning products. However, state regulations can be more stringent – notably, the California Air Resources Board (CARB) often enforces stricter VOC limits than the EPA, so manufacturers often have to comply with both federal and tighter state requirements.

Canada

Canada restricts the concentration of volatile organic compounds (VOCs) in over 130 categories of products – from personal-care items to adhesives and automotive maintenance products. The rules are designed to protect the environment and Canadians’ health by reducing VOC emissions, which contribute to smog.

Manufacturers and importers need to ensure their products meet the concentration limits and keep documentation to demonstrate compliance.

European Union

The Directive 2004/42/EC on the limitation of emissions of volatile organic compounds due to the use of organic solvents in certain paints and varnishes and vehicle-refinishing products, which limits VOC content in these products.

The Industrial Emissions Directive (2010/75/EU), which regulates VOC emissions from various industrial activities, including the use of organic solvents.

The EU also classifies organic compounds by boiling point into the very volatile (VVOC), volatile (VOC) and semi-volatile (SVOC) categories, which is widely used in scientific literature.

China

China has rolled out comprehensive action plans to curb VOC pollution, focusing on high‑emission sectors like petrochemicals, coatings and printing. It has also introduced mandatory national standards that limit VOC content in products like paints, adhesives and inks. Meanwhile, the government is pushing for wider adoption of water‑based and low‑VOC coatings, inks and adhesives to replace solvent‑based alternatives.

India

Unlike many other countries, India does not have a single, nationwide regulation that covers all VOCs. Instead, the country relies on sector-specific standards: the Ministry of Environment, Forest and Climate Change has set emission limits for certain industries, which indirectly help control VOC releases. The ambient air quality rules in India set limits for benzene, but they do not include a limit for total VOCs (TVOC).

How to reduce VOC exposure

Want to cut your exposure to volatile organic compounds (VOCs)? Then focus on these three simple things:

1. Improve your indoor air quality.

2. Choose products with lower VOCs.

3. Use good ventilation paired with preventative measures.

   
   

Improving indoor air quality

If you want to cut down on indoor VOCs, try these simple, practical steps:

• Open windows and run fans whenever possible to boost airflow. Fresh air dilutes VOCs quickly, especially after painting or cleaning.

• Use an air purifier that includes an activated carbon filter. Those filters trap many of the gases particle filters miss.

• Keep indoor temperature and humidity on the lower side if you can. Cooler, drier air slows the release of VOCs from materials and finishes.

• Clean regularly and vacuum with a HEPA-equipped machine when you can. Dust and tiny particles can carry VOCs, so removing them lowers overall exposure.

Safer product choices

To reduce your exposure to indoor VOCs, try these tips:

• Choose products labeled as "low‑VOC" or "no‑VOC" – they will emit far fewer volatile organic compounds.

• Opt for solid wood furniture and cabinets instead of composite wood, which can off-gas formaldehyde.

• Cut back on air fresheners, scented candles, and other fragrance products, which can add VOCs to the indoor air.

• Use integrated pest management (IPM) to keep pests under control and minimize the need for pesticides indoors.

Ventilation and prevention strategies

Simple steps to reduce your indoor exposure to VOCs:

• Keep the area well ventilated during and after tasks like painting, cleaning, or using hobby products that release fumes.

• Buy only the amount of chemicals you need so you don’t end up storing partially used, open containers.

• Store products that contain VOCs in tightly sealed containers, ideally in a well-ventilated spot outside the main living area, such as a garage or shed.

• Follow the manufacturer’s instructions for using and disposing of any product that contains VOCs.

• Let new furniture or building materials “off‑gas” in a well-ventilated space before bringing them into your home so initial fumes can dissipate.

Measuring and monitoring VOCs

Why measure volatile organic compounds (VOCs)? Because they directly shape air quality and influence how much people are exposed. By monitoring VOCs indoors and outdoors, we can assess those risks and decide what to do about them. To that end, a variety of measurement methods are used, chosen to fit each setting and purpose.

Indoor air testing

Wondering how to test indoor air for VOCs? Here are some practical options:

• Sorbent (adsorption) tubes: These tubes collect a sample of air that can be sent to a lab for detailed analysis.

• Portable VOC monitors: Handheld devices that provide real-time readings of total VOCs (TVOC), useful for spotting changes instantly.

• Lab testing with GC-MS: To identify and quantify specific compounds, laboratories use sophisticated techniques like gas chromatography-mass spectrometry.

Testing is especially recommended for new or recently renovated buildings, as building materials can off-gas significantly into the indoor air.

Environmental monitoring methods

Environmental monitoring of volatile organic compounds (VOCs) typically starts with collecting samples of air, water or soil for later analysis. For air, teams often use stainless‑steel canisters or gas sampling bags to capture representative samples.

In the lab, gas chromatography (GC) with detectors like the flame ionization detector (FID) or the electron capture detector (ECD) is a common choice for VOC analysis. For real‑time atmospheric measurements, proton‑transfer‑reaction mass spectrometry (PTR‑MS) is frequently used.

Before analysis, technicians usually preconcentrate VOCs using techniques such as cold traps or solid‑phase microextraction (SPME), which help gather trace compounds from the sample.