Ozone (O₃) in your home: a safety profile
High risk for your homeInhalation is the only relevant exposure route; ozone reacts within the respiratory tract and does not penetrate systemically in significant amounts. Regional dose depends on breathing pattern: high ventilation during exercise dramatically increases O₃ dose to distal airways. At 0.08 ppm: lung function decrements measurable in exercising children. At 0.12 ppm: significant chest pain and cough in majority of exercising adults (clinical endpoint used in older NAAQS). Indoor ozone sources: photocopiers, air purifiers with ionizers, and infiltration from outdoor air. Indoor chemistry: ozone + monoterpenes (e.g., limonene from citrus cleaning products) generates ultrafine particles and formaldehyde.
What is ozone (o₃)?
The IUPAC name is ozone.
Also known as: ozone, Triatomic oxygen, Ozon, Ozone heavy work.
- IUPAC name
- ozone
- CAS number
- 10028-15-6
- Molecular formula
- O3
- Molecular weight
- 47.998 g/mol
- SMILES
- [O-][O+]=O
- PubChem CID
- 24823
Risk for your household
High riskInhalation is the only relevant exposure route; ozone reacts within the respiratory tract and does not penetrate systemically in significant amounts. Regional dose depends on breathing pattern: high ventilation during exercise dramatically increases O₃ dose to distal airways. At 0.08 ppm: lung function decrements measurable in exercising children. At 0.12 ppm: significant chest pain and cough in majority of exercising adults (clinical endpoint used in older NAAQS). Indoor ozone sources: photocopiers, air purifiers with ionizers, and infiltration from outdoor air. Indoor chemistry: ozone + monoterpenes (e.g., limonene from citrus cleaning products) generates ultrafine particles and formaldehyde.
Regulatory consensus
7 regulatory and scientific bodies have classified Ozone (O₃). The classifications differ — that's the data.
| Agency | Year | Classification | Notes |
|---|---|---|---|
| WHO | — | criteria air pollutant | Ozone is designated as a WHO criteria air pollutant |
| US EPA | — | criteria air pollutant | Ozone is designated as an EPA criteria air pollutant |
| US EPA | — | not classified as a human carcinogen | EPA has not classified ozone as a human carcinogen; primary hazard is respiratory and cardiovascular injury |
| US EPA | 2015 | NAAQS: 70 ppb (8-hour) | National Ambient Air Quality Standards, revised 2015 |
| EPA CTX / Genetox | — | Genotoxicity: positive (Ames: positive, 8 positive / 7 negative reports) | |
| EPA CTX / Genetox | — | Genotoxicity: positive (Ames: positive, 8 positive / 7 negative reports) | |
| EPA CTX / Skin-Eye | — | Eye Irritation: Category 2A-2B (score: high) |
Regulators apply different standards of evidence — animal-data weighting, exposure-pattern assumptions, epidemiological power thresholds — which is why two scientific bodies can review the same data and reach different conclusions. The disagreement is the data.
Where your home encounter ozone (o₃)
- Outdoor Air — Vehicle exhaust, Industrial emissions, Power plant discharge
- Indoor Air — Combustion byproducts, Office buildings, Parking garages
Safer alternatives
Lower-risk approaches that achieve a similar outcome to Ozone (O₃):
-
Physical/mechanical pest control (IPM)
Trade-offs: More labor-intensive. May not be sufficient for severe infestations.Relative cost: 1.2-2×
Frequently asked questions
Is ozone (o₃) safe for your home?
Inhalation is the only relevant exposure route; ozone reacts within the respiratory tract and does not penetrate systemically in significant amounts. Regional dose depends on breathing pattern: high ventilation during exercise dramatically increases O₃ dose to distal airways. At 0.08 ppm: lung function decrements measurable in exercising children. At 0.12 ppm: significant chest pain and cough in majority of exercising adults (clinical endpoint used in older NAAQS). Indoor ozone sources: photocopiers, air purifiers with ionizers, and infiltration from outdoor air. Indoor chemistry: ozone + monoterpenes (e.g., limonene from citrus cleaning products) generates ultrafine particles and formaldehyde.
What products contain ozone (o₃)?
Ozone (O₃) appears in: Vehicle exhaust (Outdoor air); Industrial emissions (Outdoor air); Combustion byproducts (Indoor air); Office buildings (Indoor air).
Why do regulators disagree about ozone (o₃)?
Ozone (O₃) has been classified by 7 agencies including WHO, US EPA, US EPA, US EPA, EPA CTX / Genetox, with differing conclusions. Regulators apply different standards of evidence (animal data weighting, exposure-pattern assumptions, epidemiological power thresholds), which is why two scientific bodies can review the same data and reach different conclusions. See the regulatory consensus table on this page for the full picture.
See Ozone (O₃) in the home app
Look up products containing ozone (o₃), compare to alternatives, and explore the full data record.
Open in home View raw API dataSources (3)
- US EPA National Ambient Air Quality Standards for Ozone — 2015 Final Rule (2015) — regulatory
- WHO Air Quality Guidelines for Ozone (Global Update 2021) (2021) — regulatory
- ATSDR Minimal Risk Levels for Ozone (2012) — report
Reference data, not professional advice. Aggregates publicly available regulatory and scientific data; not a substitute for veterinary, medical, legal, or regulatory advice. Why we built ALETHEIA →