Someone walks past wearing too much scent. Your eyes sting and your throat goes scratchy before your brain has even named the smell. Scent is supposed to be a smell. For a lot of eyes, noses, and throats, it’s more than that. Here’s what lab, animal, and population studies have found about fragrance and your airways, where the evidence is split, and why the industry’s own safety models left breathing out for years.
Evidence key Strong Moderate Weak How we grade
For years, the industry’s safety models skipped breathing
Start with how the people who call fragrance safe measured your exposure.
The fragrance industry's aggregate consumer exposure model began in 2015 covering 19 personal-care and cosmetic product types across a 36,446-subject Europe/US survey, using dermal and oral exposure routes only — it did not estimate inhaled fragrance exposure at all. Moderate evidence. Comiskey 2015 (RIFM/Creme Global) Industry-funded
The fragrance industry's aggregate consumer exposure model did not include any estimate of inhaled fragrance exposure until 2017, when it added an inhalation route for air fresheners, scented candles, and personal-care sprays only — 23 years after the industry's 1994 safety package dismissed inhalation testing. Moderate evidence. Comiskey 2017 (RIFM/Creme Global) Industry-funded
Then there’s the regulator side, where the standard test for this kind of irritation has a limited role.
Under the EU's REACH chemical regulation, data from the mouse sensory-irritation bioassay are generally not accepted to classify a chemical as causing respiratory tract irritation (that classification is limited to tests showing direct tissue damage); the bioassay's data can only be used case-by-case to help set a short-term safe-exposure value. Moderate evidence. Nielsen & Wolkoff 2017 Industry-funded
That sting in your eyes is irritation, not allergy
Here’s what the research says is going on instead.
Burning, stinging, or itching sensations in the eyes, nose, and throat from airborne chemicals are caused by a specific, receptor-mediated nerve reflex (activation of TRPV1, TRPA1, TRPM8, and related channels on trigeminal nerve endings), not by allergy or immune response. Moderate evidence. Nielsen & Wolkoff 2017 Industry-funded
One research group tested this with perfume itself.
The eye irritation from perfume vapor was not an allergy: people patch-test allergic to the very same perfume were no more likely to react than those who were not. Moderate evidence. Elberling 2006
The excess basophil reactivity to perfume in symptomatic patients was not explained by allergy antibodies in the blood (a passive-serum-transfer test found no difference between groups) and did not track whether a patient also had a skin (contact) allergy, an inhalant allergy, or asthma. Moderate evidence. Elberling 2007
Allergy tests don’t explain every reaction. See Scent and your lungs: allergy or irritation?
What population studies found in people
These studies found links, not proof of cause. They are still worth knowing about.
In a population-representative sample of about 2,900 Canadians (Canadian Health Measures Survey, 2012-2013), a 100% increase in measured residential indoor-air limonene was associated with a 17-18% relative increase in the adjusted odds of both wheezing (OR 1.17, 95% CI 1.16-1.18) and doctor-diagnosed asthma (OR 1.18, 95% CI 1.17-1.19), plus a 1.55% (95% CI 1.28-1.89) increase in exhaled nitric oxide (FeNO), an objective marker of airway inflammation. Moderate evidence. Dales & Cakmak 2019 Industry-funded
In a large Canadian population survey, more frequent use of personal care products was associated with small but statistically significant reductions in objectively measured lung function. Moderate evidence. Dales 2013
Restricting the analysis to never-smokers did not remove the association between personal care product use and lower lung function in women. Moderate evidence. Dales 2013
And in Germany, the complaint wasn’t mostly about skin.
In a nationally representative German survey, one in five adults (19.9%) report at least one health effect from fragranced products, and more than half of them (55.3%) report respiratory problems, not skin problems — the focus of most prior German fragrance research. Moderate evidence. Klaschka 2020a
In mice: colognes, an air freshener, and dryer sheets
These are animal studies at concentrations far above normal indoor air. One commercial lab ran them on everyday products. The doses weren’t measured or matched to real homes, so read them for what they are.
Mice breathing the vapor of five ordinary commercial colognes for one hour showed airway irritation and a 30-35% drop in mid-expiratory airflow, despite never having been exposed to any allergen or asthma trigger. Moderate evidence. Anderson & Anderson 1998
Mice breathing the vapor of one commercial solid air freshener for one hour showed dose-dependent airway irritation and, at higher doses, a ~35% fall in mid-expiratory airflow — the same magnitude reported for colognes in the same lab's companion study. Moderate evidence. Anderson & Anderson 1997
Then the dryer sheets, including the ones that say “unscented.”
In a mouse inhalation screening study, all five commercial fabric-softener dryer pads tested (three scented, two labeled unscented) caused significant sensory irritation (21-58% of breaths) and airflow limitation (6-32%) compared to sham exposure, and two of the five brands also caused significant pulmonary irritation (12% and 23%); the two 'unscented'-labeled brands were just as irritating as the scented ones. Moderate evidence. Anderson & Anderson 2000
Even the shirt that came out of the dryer counted.
In the same study, a cotton tee-shirt that had already been dried with a fabric-softener pad — not the pad itself — still emitted enough residual chemical to cause significant sensory irritation in mice (49% of breaths, versus 6% for an unwashed new shirt), at a much lower bulk air concentration (86 ppm) than the raw pad's headspace. Moderate evidence. Anderson & Anderson 2000
When the tests found less, and who they left out
Not every study finds a problem, and we’d rather show you than hide it. Start with how the most common scents compare with the level that irritates.
The four most common airborne fragrances in homes and offices, pinene, limonene, linalool, and eugenol, are usually present at levels 2 to 3 times below the concentration needed to physically irritate the eyes and airways, but at or above the much lower level needed just to smell them. Moderate evidence. Wolkoff & Nielsen 2017
In one small lab test on eyes, at limonene levels above typical indoor air, adding ozone changed the result.
A 10-minute-old reacted mixture of limonene and ozone (residual 75 ppb limonene + 40 ppb ozone) raised human eye-blink frequency 42% relative to clean air, while the same men's eyes exposed separately to just limonene, or just ozone, at similar or higher levels, did not blink more. Moderate evidence. Klenø & Wolkoff 2004
Two larger studies measured something different and found no rise in reported irritation.
In the two largest, most realistic human tests to date, breathing a fragrance-and-ozone reaction mixture (the kind formed when a citrus-scented product meets indoor ozone) produced no measurable increase in eye, nose or throat irritation, in either healthy people, or asthmatics. Moderate evidence. Wolkoff & Nielsen 2017
Those tests have a blind spot, though. Look at who got excluded.
Every controlled chamber study in a 103-study review of asthma and airborne chemicals excluded people with moderate or severe asthma by design; the one study that directly compared severity groups found the more severe group had the largest airway response, though not statistically significant in that small sample. Strong evidence. Johansson 2016
What scent and ozone make in mice
These are animal studies at concentrations far above normal indoor air.
In a mouse study, when scientists physically separated the invisible ultrafine particles from the gas fumes made by citrus-scent limonene reacting with ozone, the airway-irritating effect disappeared entirely, showing it's the gas products, led by formaldehyde, that irritate, not the particles themselves. Moderate evidence. Wolkoff et al. 2008
Of five common ozone-terpene reaction products tested in mice (4-AMCH, dihydrocarvone, IPOH, 6-MHO, and 4-OPA), the study's own conclusion was that four do not contribute substantially to airway irritation at indoor or ambient concentrations; only IPOH (sensory irritation) and 4-OPA (airflow limitation) were flagged as compounds of concern warranting precaution against excess formation. Moderate evidence. Wolkoff et al. 2012/2013
In one voice clinic, perfume was a named trigger
In the clinical case series that first defined "irritable larynx syndrome," perfume was a named symptom trigger in about a quarter of patients (10 of 39), well behind reflux (72%) and other airborne irritants (51%). Moderate evidence. Morrison 1999
One small study found a touchier cough reflex
This Swedish clinic study measured coughing after capsaicin, not perfume, in people who reported symptoms from scents and chemicals.
In a small Swedish clinic study, people whose breathing symptoms were triggered by scents and chemical irritants — but who had normal lung function and negative allergy and asthma tests — coughed much more after inhaling capsaicin (the hot-pepper compound) than either people with verified asthma or healthy volunteers (93 vs 23 average coughs at the highest dose, P<0.001). Moderate evidence. Millqvist, Bende & Löwhagen 1998
The extra coughing in these chemically sensitive patients could not be explained by asthma: their lung function, methacholine reactivity, and skin-prick allergy testing were all normal, yet they still coughed dose-dependently to inhaled capsaicin, and even to a plain saline control, while a separate group of people with verified asthma did not cough more than healthy volunteers. Moderate evidence. Millqvist, Bende & Löwhagen 1998
Where the evidence is split
Not every test lines up, and that’s worth knowing before anyone oversells it, including us.
Moderate asthmatics self-reported more nasal congestion after one of two fragranced aerosols, but objective nasal-airway measurement (acoustic rhinometry) on the same people at the same time found no change. Moderate evidence. Opiekun 2003 Industry-funded
Despite reporting more symptoms at higher VOC concentrations, the same subjects showed no significant change in lung function (FEV1, FVC) or in nasal-lavage and induced-sputum cell counts and inflammatory markers (neutrophils, IL-8, LTB4, albumin) at 25 or 50 mg/m3. Moderate evidence. Pappas et al. 2000, Int J Occup Environ Health 6:1-8
What you can do
If a strong, lingering chemical smell gets in your eyes or throat, don’t tough it out.
Treat a strong, persistent solvent-type smell (heavy cleaning, fresh paint, new furnishings in a poorly ventilated space) as a plausible trigger for eye, nose, throat, or mild respiratory irritation, and ventilate or leave the area if symptoms appear. Moderate evidence. Pappas et al. 2000, Int J Occup Environ Health 6:1-8
Keep the dryer venting outside.
An independent indoor-air chemist (Charles Weschler) cautioned that the reported dryer-vent acetaldehyde concentrations are high enough to raise sensory-irritation concern if dryers are vented indoors, whether intentionally via indoor dryer-vent kits or unintentionally through equipment malfunction. Moderate evidence. Kessler 2011 (EHP Forum)
- Cut the sources: air fresheners, scented candles, plug-ins, and scented laundry products. Our guides to air fresheners and scented laundry show where to start.
- If you have asthma, read fragrance and asthma, and if you clean for a living, spray cleaners and disinfectants.
- If scent at work gets in your eyes or throat, the workplace guide and the letter builder help you ask for a change. A no-scent sign helps too.
- Check ingredients with the label decoder before you buy.
Every claim above shows its evidence grade and names its source. See all the facts and the claims we won’t make. Information, not medical advice.
