Indoor environment factor · measured in µg/m³ or ppb (TVOC); mg/m³ for single compounds
Volatile organic compounds (VOCs)
Also: VOC, TVOC, total volatile organic compounds
Carbon-based chemicals that evaporate easily at room temperature — formally, compounds with a vapour pressure of at least 0.01 kPa at 20 °C. Indoors they come from paints, furniture, cleaning products, cosmetics and people, and are measured collectively as total VOCs (TVOC).
Why it matters indoors
Volatile organic compounds are the gases given off by almost everything made, cleaned or worn indoors. The defining property is volatility: they evaporate at ordinary temperatures, which is exactly why paint dries, why a new sofa smells and why a cleaned bathroom smells of lemon. Thousands of individual compounds fall under the label, so indoor monitoring usually reports them collectively as total VOCs.
Where they come from indoors
Building products and furniture (paints, adhesives, sealants, laminates, foams), cleaning and personal-care products (solvents, fragrances, aerosols), office equipment, cooking and combustion, and the occupants themselves — breath and skin emit measurable amounts, which is why TVOC rises in a full meeting room even without any product in use. Outdoor traffic contributes benzene and other aromatic compounds.
Health effects
Short-term: irritation of the eyes, nose and throat, headache, dizziness and nausea — the classic “sick building” complaints. Long-term effects depend on the compound: several are carcinogens (benzene, formaldehyde), others damage the liver, kidneys or nervous system with chronic exposure. Sensitivity varies widely; people with asthma and children react at lower concentrations.
Exposure limits
Because VOCs are a category, there is no single limit. Regulators set values for individual compounds — formaldehyde and benzene have their own pages — and some jurisdictions publish TVOC guidance:
| Jurisdiction | Value | Basis | Source |
|---|---|---|---|
| World Health Organization | none for TVOC; compound-specific values for formaldehyde, benzene, naphthalene and others | — | WHO indoor air quality guidelines 2010 |
| European Union | product-emission limits (paints, varnishes) rather than indoor concentrations | Directive 2004/42/CE | EU |
Slovak, UAE and Hong Kong values are being compiled in the indoor air quality limits table.
How they are measured
Laboratory reference methods collect air on sorbent tubes and identify compounds by gas chromatography. Continuous sensors use metal oxide semiconductors or photoionisation detectors that respond to the overall load of oxidisable gases; they are excellent at showing when a source appears and how quickly ventilation removes it, but they cannot tell which compound is present.
What the studies report
12 of 61 Findings — those with the strongest study design.
| Linked to | Effect | Population | Study design | Source | Checked |
|---|---|---|---|---|---|
| Biomass fuel | mean 1361.79 | — · home | review of studies of indoor air pollution in Ethiopian households with calculated mean concentrations across the included studies: particulate matter, nitrogen dioxide, total volatile organic compounds, polycyclic aromatic hydrocarbons and carbon monoxide, by geography, stove type and household activity | F-1002 Asefa Human exposure to indoor air pollution in Ethiopian househol… (2022) | machine |
| Cardiovascular disease (CVD) | OR 1.57 (0.79–3.11) · borderline | — | systematic review and meta-analysis of 36 studies of volatile organic compound exposure and cardiovascular disease: random-effects and fixed-effects pooled estimates for volatile organic compound mixtures, for toluene, ethylbenzene and xylene, and for benzene against cardiovascular death | F-1194 Exposure to volatile organic compounds and cardiovascular di… (2026) | machine |
| Indoor plants (phytoremediation) | a single plant species in one laboratory room, measured over 40 minutes | — · university laboratory | experiment with four ornamental potted plants as a plant-based biofilter: benzene, toluene, benzaldehyde and acetophenone in an incubation chamber and then indoor air quality parameters measured in a pharmaceutical laboratory with and without the plants, over standardised 40-minute sessions | F-1051 Comparative evaluation of air phytoremediation potential of … (2025) | machine |
| Indoor plants (phytoremediation) | a stated direction without a number; both groups still had the plants during this term, so the decrease is not a contrast between them | asthmatics and their households · home | quasi-experimental study in the homes of asthmatics in Korea over two observation terms: households of continuation kept the indoor plants for both terms, households of withdrawal kept them for the first term and passed the second without any plants; formaldehyde and benzene, toluene, ethylbenzene and xylene were measured indoors, with peak expiratory flow rate twice a day and an asthma-specific quality of life questionnaire, compared with the Mann-Whitney test | F-1224 House-plant placement for indoor air purification and health… (2014) | machine |
| Indoor plants (phytoremediation) | a stated direction without a number; the study also says formaldehyde fell with passing time in both groups, so not all of the decrease belongs to the plants | asthmatics and their households · home | quasi-experimental study in the homes of asthmatics in Korea over two observation terms: households of continuation kept the indoor plants for both terms, households of withdrawal kept them for the first term and passed the second without any plants; formaldehyde and benzene, toluene, ethylbenzene and xylene were measured indoors, with peak expiratory flow rate twice a day and an asthma-specific quality of life questionnaire, compared with the Mann-Whitney test | F-1227 House-plant placement for indoor air purification and health… (2014) | machine |
| Indoor plants (phytoremediation) | a stated direction without a number; formaldehyde and toluene are the exceptions the sentence names, and their concentrations kept falling | asthmatics and their households · home | quasi-experimental study in the homes of asthmatics in Korea over two observation terms: households of continuation kept the indoor plants for both terms, households of withdrawal kept them for the first term and passed the second without any plants; formaldehyde and benzene, toluene, ethylbenzene and xylene were measured indoors, with peak expiratory flow rate twice a day and an asthma-specific quality of life questionnaire, compared with the Mann-Whitney test | F-1228 House-plant placement for indoor air purification and health… (2014) | machine |
| Emission test chamber method | the study reads the absence of a dependence as the body regulating its own surface temperature and humidity, and contrasts it with the pronounced humidity dependence reported for skin oil on materials | three adult volunteers · test chamber | single-person chamber experiments with three volunteers at Tsinghua University: emission fluxes of the products of skin oil ozonolysis measured with a proton transfer reaction mass spectrometer with and without ozone injection, while air temperature, relative humidity, bathing frequency, clothing soiling and clothing coverage were varied one at a time | F-1252 Influence of Temperature, Humidity, Personal Hygiene, and Cl… (2025) | machine |
| Emission test chamber method | difference 25 | three adult volunteers · test chamber | single-person chamber experiments with three volunteers at Tsinghua University: emission fluxes of the products of skin oil ozonolysis measured with a proton transfer reaction mass spectrometer with and without ozone injection, while air temperature, relative humidity, bathing frequency, clothing soiling and clothing coverage were varied one at a time | F-1253 Influence of Temperature, Humidity, Personal Hygiene, and Cl… (2025) | machine |
| Emission test chamber method | the study reads the absence of an effect as skin oil re-equilibrating quickly on the body surface | three adult volunteers · test chamber | single-person chamber experiments with three volunteers at Tsinghua University: emission fluxes of the products of skin oil ozonolysis measured with a proton transfer reaction mass spectrometer with and without ozone injection, while air temperature, relative humidity, bathing frequency, clothing soiling and clothing coverage were varied one at a time | F-1254 Influence of Temperature, Humidity, Personal Hygiene, and Cl… (2025) | machine |
| Emission test chamber method | difference 50 | three adult volunteers · test chamber | single-person chamber experiments with three volunteers at Tsinghua University: emission fluxes of the products of skin oil ozonolysis measured with a proton transfer reaction mass spectrometer with and without ozone injection, while air temperature, relative humidity, bathing frequency, clothing soiling and clothing coverage were varied one at a time | F-1255 Influence of Temperature, Humidity, Personal Hygiene, and Cl… (2025) | machine |
| Emission test chamber method | a stated direction without a number; the study reads ozone as the key factor regulating these emissions | three adult volunteers · test chamber | single-person chamber experiments with three volunteers at Tsinghua University: emission fluxes of the products of skin oil ozonolysis measured with a proton transfer reaction mass spectrometer with and without ozone injection, while air temperature, relative humidity, bathing frequency, clothing soiling and clothing coverage were varied one at a time | F-1256 Influence of Temperature, Humidity, Personal Hygiene, and Cl… (2025) | machine |
| Emission test chamber method | the register has no slug for these individual products, so they are named here; a yield, not a room concentration | three adult volunteers · test chamber | single-person chamber experiments with three volunteers at Tsinghua University: emission fluxes of the products of skin oil ozonolysis measured with a proton transfer reaction mass spectrometer with and without ozone injection, while air temperature, relative humidity, bathing frequency, clothing soiling and clothing coverage were varied one at a time | F-1257 Influence of Temperature, Humidity, Personal Hygiene, and Cl… (2025) | machine |
Each row is one Finding — a sentence as printed in one study, recorded with its page in the Coridum Knowledge Base. Follow the Finding number for the exact wording and the citation. Checked says who verified the row: machine means every automatic check passed and the surrounding text was read; person means someone read the sentence in the document. Rows are re-checked by a person over time. The studies are curated in the Coridum Knowledge Base; the reading of them together is a Claim, shown separately.
How strong is the evidence
-
A single study suggests that installing laminate flooring raises the concentration of total volatile organic compounds indoors immediately after installation.
-
In children, raised urinary metabolites of volatile organic compounds are more common in those with atopic dermatitis.
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In children, a single day-care cohort suggests that a rise in indoor toluene is followed two days later by more symptoms of atopic dermatitis; for benzene the same study found the association borderline and not statistically significant.
-
In children attending daycare, a single French study suggests that higher indoor concentrations of two solvents — methyl isobutyl ketone and 1-methoxy-2-propyl acetate — go together with recurrent wheeze; for two further compounds the association did not survive correction for multiple testing.
A Claim is Coridum reading the Findings together, not a quotation from one study — according to Coridum. The grade follows the study designs behind it: A is the strongest, D means a single study or a mechanism.
How Coridum measures it: Coridum devices use a metal oxide semiconductor sensor that reports total VOCs as an index and an equivalent concentration; it cannot identify individual compounds, but it tracks changes and sources precisely.
Identifiers
- MeSH
- D055549
Frequently asked questions
What is a normal TVOC level indoors?
Well-ventilated homes typically sit below 300 µg/m³. Levels between 300 and 1000 µg/m³ usually mean a source is present (new furniture, recent painting, cleaning); above 1000 µg/m³ is considered elevated and worth acting on. Note that TVOC values from different sensor types are not directly comparable.
Are all VOCs harmful?
No. The category covers thousands of compounds, from harmless plant terpenes to carcinogens such as benzene and formaldehyde. TVOC is a useful indicator of sources and ventilation, not a measure of toxicity.
How long does new furniture off-gas?
Emissions are highest in the first weeks and fall steadily, but pressed-wood products can release formaldehyde for years. Ventilating a room with new furniture for the first month reduces peak exposure substantially.
Sources
- WHO guidelines for indoor air quality: selected pollutants. World Health Organization Regional Office for Europe, 2010.
- Directive 2004/42/CE on the limitation of emissions of volatile organic compounds due to the use of organic solvents in certain paints and varnishes.
- Catalytic Combustion of Volatile Organic Compounds (VOCs) over Perovskite Oxides: A Review (2023). Asian Journal of Chemistry. doi:10.14233/ajchem.2023.30271 CKB 0819
- Li Profiles and monthly variations of selected volatile organic compounds in indoor air in Canadian homes_ Results of Canadian national indoor air survey 2012–2013 (2019). doi:10.1016/j.envint.2019.02.035 CKB 0164
- Liquid crystal display screens as a source for indoor volatile organic compounds…. Proceedings of the National Academy of Sciences of the United States of America. doi:10.1073/pnas.2105067118 CKB 0232
CKB = document number in the Coridum Knowledge Base, our curated library of peer-reviewed studies. Follow the DOI for the original paper.
Cite this page
Coridum Research. Volatile organic compounds (VOCs). Coridum Knowledge G-0002, 16 September 2026. https://coridum.com/k/G-0002/