Don’t take our word for it. Here’s every fact on this site, with its evidence grade, its caveats, and a link to the source, so you can check us.
We start you on the strong ones: findings that have been replicated or come from one large, well-controlled study. Moderate and weak facts are here too, labeled for what they are. Use “Link to this fact” to share a single card.
Indoor air / Animal study
Air brought from a federal office building under litigation for poor indoor air quality (carried to the lab in sealed bags) caused the same objective sensory-irritation signature in mice as the consumer-product tests, dropping their respiratory rate to about 46% of baseline before partial recovery; air from buildings people considered acceptable did not cause this effect.
Moderate evidence: Single building, single lab, one comparison air sample; the underlying human complaints were not independently verified against objective health measures in this paper.
Source: Anderson & Anderson 1999, Toxicology and Industrial Health Link to this fact
Indoor air / Measured in people or real products
Modeled deposited aerosol dose from a single one-minute use of a consumer spray varied by about four orders of magnitude across 10 tested products (roughly 0.1 to 1,335 nanograms per kg body weight), and for most products (8 of 10) about 85-88% of the deposited aerosol mass landed in the head airways (nose/throat) rather than deeper in the lungs.
Moderate evidence: Deposited dose is a modeled physical mass estimate, not a measured systemic or biological dose; single-lab study of 10 products, one 1-minute exposure event per product.
Source: Nazarenko 2014, Environmental Science: Nano Link to this fact
Indoor air / Measured in people or real products
Two silver spray products (a 'nano' and a 'regular' version) were the exception to the head-airways pattern: despite having the lowest total deposited aerosol doses of any product tested (2-4 orders of magnitude below the other 8 sprays), a much larger share of their deposited dose — about 29% and 40% respectively — reached the deep alveolar region of the lungs, versus 7-9.5% for the other 8 sprays.
Moderate evidence: Absolute alveolar doses from these two products were still very small in absolute terms because total exposure was so low; this is a proportional, not absolute, finding.
Source: Nazarenko 2014, Environmental Science: Nano Link to this fact
Indoor air / Measured in people or real products
Not noticing a chemical or fragrance smell in your home or workplace anymore does not mean it is gone: electro-olfactogram recordings show peripheral smell receptors stay measurably responsive to a steady background odor even after conscious perception of it has faded, because habituation happens mainly in the brain, not the nose.
Moderate evidence.
Caveats
Evidence is from small human electrophysiology studies of perception, not from measurements of continued chemical absorption, dose, or health effect; this paper does not address whether continued unnoticed exposure is harmful.
Source: Pellegrino 2017, Physiology & Behavior Industry-funded Link to this fact
Indoor air / Other evidence
For hairspray, deodorant, and eau de toilette sprayed at the head or upper body, about 85% of the sprayed product deposits on hair, skin, or other surfaces and only about 15% stays in the air available for inhalation, as a default in the absence of product-specific measurement.
Moderate evidence.
Caveats
The only cited direct measurement behind a comparable number is a 2012 deodorant/antiperspirant aerosol study (76.5-88.6% available for inhalation, i.e., 11.4-23.5% deposited) — a different, narrower product set than hairspray/eau de toilette.
Source: Steiling et al. 2025, Toxicology Letters Industry-funded Link to this fact
Indoor air / Other evidence
Sprayed cosmetic droplets are mostly gone from the breathing zone within minutes: about 35% clear in the first minute after spraying and about 95% clear within eight minutes, which is why the authors recommend a standard 10-minute exposure duration for modeling.
Moderate evidence: The 35%/95% clearance figures are cited from a single 2021 CIR resource document, not independently replicated here.
Source: Steiling et al. 2025, Toxicology Letters Industry-funded Link to this fact
Indoor air / Measured in people or real products
In controlled chamber testing of 12 cosmetic spray products (sunscreens, dry shampoos, hair sprays, a moisturizing and a setting spray, and perfumes) applied 20 cm from the measurement point, one sunscreen spray reached a maximum PM10 particle-number concentration of 1.03 x 10^6 particles per cubic centimeter, and another reached a maximum PM10 mass concentration of 36.17 mg per cubic meter.
Moderate evidence.
Caveats
Single lab, chamber-based, near-field (20 cm) measurement of the immediate spray plume, not a room-average or personal-exposure measurement; one unit tested per product; no replication by an independent group yet.
Source: Dai et al. 2026, ACS Environmental Au Link to this fact
Indoor air / Measured in people or real products
Propellant-based cosmetic sprays (sunscreen, dry shampoo, hair spray) emitted far more submicron particles than pump-based sprays: the two pump perfumes tested stayed below 100 particles per cubic centimeter across all size fractions, while propellant sprays ranged up to hundreds of thousands of particles per cubic centimeter.
Moderate evidence.
Caveats
12 products from unnamed brands, single lab; propellant vs. pump delivery is confounded with product type (perfumes vs. sunscreens/hair sprays), so the difference cannot be attributed to propellant use alone.
Source: Dai et al. 2026, ACS Environmental Au Link to this fact
Indoor air / Measured in people or real products
Modeling with the Multiple-Path Particle Dosimetry (MPPD) model estimated that a single use of one dry-shampoo spray could deposit up to 1.38 x 10^10 submicron particles in the respiratory tract, mostly by particle count rather than mass (total deposited mass below 50 micrograms), while sunscreen sprays delivered the highest total deposited mass, up to about 2.22 milligrams per use.
Moderate evidence.
Caveats
Deposition doses are model estimates (MPPD), not measured in a human airway; the model did not account for hygroscopic particle growth or electrostatic charge, which the authors say makes the net effect on total dose uncertain.
Source: Dai et al. 2026, ACS Environmental Au Link to this fact
Indoor air / Measured in people or real products
Among the 9 air fresheners where diethyl phthalate (DEP) was detected, NRDC's 2007 test found levels ranging from 0.78 ppm to 7,300 ppm, averaging 977 ppm among DEP-containing products.
Moderate evidence: Single lab, single sample per product, not independently replicated.
Source: NRDC 2007, Clearing the Air Link to this fact
Indoor air / Measured in people or real products
At one Taoist temple in Yi-Lan, Taiwan, both particle mass and total PAH content peaked in the submicrometer 0.1-1.0 um size fraction of temple incense-burning particles: 119.0 (SD 35.2) ug/m3 particle mass and 0.19 (SD 0.002) ug/m3 total PAHs, versus 31.0/4.8 ug/m3 particle mass and 0.07/0.02 ug/m3 PAHs for the 1.0-10 um and sub-0.1 um fractions.
Moderate evidence: Field measurement from a single temple over 13 sampling days (2010); does not generalize to other temples, incense products, or ventilation conditions.
Source: Lin 2012, Science of The Total Environment Link to this fact
Indoor air / Test-chamber measurement
Unscented reference candles emitted far less formaldehyde, benzene, and fragrance chemicals than otherwise-similar scented candles from the same study, across both small and large test chambers.
Moderate evidence: Single-lab dataset; consistent with independent findings from Salthammer 2021 and Andersen 2021 that fragrance, not wax, drives candle combustion byproduct emissions.
Source: Petry 2014, Regulatory Toxicology and Pharmacology Industry-funded Link to this fact
Indoor air / Other evidence
Across 10 real, working New York City nail salons, total VOC levels (measured in real time with a photoionization detector) averaged almost 10 times higher (32 ppm) when indoor CO2 exceeded the ANSI/ASHRAE ventilation target of 850 ppm than when the target was met (4.1 ppm).
Moderate evidence: Small (n=10), non-random convenience sample skewed toward larger, 'upscale' Manhattan salons; TVOC is an unspeciated PID sum, not a specific chemical measurement.
Source: Pavilonis, Roelofs & Blair 2018, Journal of Occupational and Environmental Hygiene Link to this fact
Indoor air / Other evidence
Mean total VOC levels measured in 10 NYC nail salons (12 ppm, median 4.0 ppm, range 0.035-67 ppm) were, in the study authors' own assessment, many times higher than would be considered acceptable in homes or office workplaces.
Moderate evidence: The paper does not give a specific numeric residential/office comparison value in text, only a qualitative 'many times greater' statement; TVOC is unspeciated.
Source: Pavilonis, Roelofs & Blair 2018, Journal of Occupational and Environmental Hygiene Link to this fact
Indoor air / Other evidence
Nail technicians' whole-blood toluene and ethyl acetate rose significantly over a single work shift (toluene 0.16→0.36 µg/L; ethyl acetate <0.16→0.51 µg/L) and post-shift levels significantly exceeded U.S. general-population (NHANES) levels for female nonsmokers.
Moderate evidence: Single small pilot study (n=10); one small cohort does not establish generalizability across the nail-salon industry.
Indoor air / Other evidence
Better ventilation (higher air changes per hour) was significantly associated with lower personal-air toluene in nail salons (Spearman r=-0.76, p=0.017), but also with higher salon-area methyl methacrylate (r=0.71, p=0.034).
Moderate evidence.
Caveats
Small sample (7 salons); the positive ACH-methyl-methacrylate correlation is the opposite of the expected direction and is only the authors' hypothesis (increased monomer evaporation at higher airflow), not confirmed.
Indoor air / Test-chamber measurement
Standardizing 196 results from 12 published potted-plant VOC-chamber studies into clean air delivery rate (CADR), the typical (median) houseplant removes VOCs at about 0.023 m3/h, roughly 4,000 times weaker than a standard portable air cleaner (~100 m3/h).
Moderate evidence.
Caveats
Best-case estimate; the underlying mass-balance models assumed negligible chamber leakage and surface sorption, both of which would inflate apparent plant removal, so true removal is likely smaller still.
Source: Cummings & Waring 2020, Journal of Exposure Science & Environmental Epidemiology Link to this fact
Indoor air / Other evidence
To match the VOC removal that ordinary outdoor-to-indoor air exchange already provides in a typical home or office (~1 h-1 air exchange rate), a room would need 10 to 1,000 potted plants per square meter of floor space.
Moderate evidence: Best-case plant-performance assumption (no chamber leakage/sorption); ceiling height held constant at 2.5 m across the analysis.
Source: Cummings & Waring 2020, Journal of Exposure Science & Environmental Epidemiology Link to this fact
Indoor air / Other evidence
Even using the best-performing plants (90th percentile of the dataset) in an unusually airtight building, one potted plant per square meter of floor area (already impractically dense for interior design) achieves only about 20% of the VOC removal that air exchange alone provides.
Moderate evidence: Requires both an unusually low air exchange rate (<0.2 h-1) and the single best-case CADRp tier; falls off quickly at more typical air exchange rates.
Source: Cummings & Waring 2020, Journal of Exposure Science & Environmental Epidemiology Link to this fact
Indoor air / Other evidence
A historical calculation (Levin 1992), using the most generous reading of the early Wolverton/NASA chamber data, found a typical ~140 m2 (1,500 ft2) house would need 680 houseplants (4.9 plants/m2) just to raise plant-driven VOC removal to 0.096 h-1, about an order of magnitude below normal air exchange and called 'obviously not attainable.'
Moderate evidence: Uses the most generous (best-case) early NASA dataset; independently replicated in direction and order of magnitude by this paper's own larger analysis.
Source: Cummings & Waring 2020, citing Levin 1992, Journal of Exposure Science & Environmental Epidemiology Link to this fact
Indoor air / Measured in people or real products
In a field study of two Michigan hotels, hotel housekeepers' and other staff's personal breathing-zone VOC exposure while working (57 ± 36 µg/m3 total target VOCs) was nearly twice the level measured by stationary indoor-area monitors in the same hotels (28 ± 15 µg/m3), and both were far above outdoor levels (mostly below detection).
Moderate evidence: Small sample (2 hotels, 22-23 personal samples); short 6-9 hour sampling shifts; not generalizable to other hotels.
Indoor air / Measured in people or real products
Hotel housekeepers' real occupational personal exposure to fragrance terpenes (mainly limonene and alpha-pinene) from direct, repeated contact with cleaning and laundry products averaged just 7.7 µg/m3, even though every cleaning product tested in the study contained terpenes (up to 64 µg/mL in one smoke-removal spray).
Moderate evidence: Occupational, not general-population exposure; short sampling window (6-9h); small sample.
Indoor air / Measured in people or real products
In this hotel study, airborne formaldehyde — the single biggest driver of estimated health risk — did not track terpene-fragrance levels or season (terpene-ozone secondary chemistry would be expected to rise with summer ozone), leading the authors to attribute it instead to building materials, furnishings, and the large volume of bedding and towels used in hotels, not to the terpene-containing cleaning and laundry products.
Moderate evidence: Attribution is inferential, not source-tested directly; the authors call for further study to verify formaldehyde sources in hotels.
Indoor air / Measured in people or real products
In a 2021 pilot study of 20 real nail salons in the NYC area, toluene (median 7.03 ppb) and d-limonene (median 4.21 ppb) were the two most abundant of 31 volatile organic compounds measured in the air, and the authors attribute the d-limonene to cleaning and disinfection products rather than nail products, since d-limonene is not a nail-product ingredient.
Moderate evidence.
Caveats
Small convenience sample (n=20), area/micro-environmental air sampling only (not personal exposure), sampled during COVID-19 when cleaning frequency was likely elevated; source attribution to cleaning products is the authors' inference, not measured (no product-ingredient data collected).
Source: Han et al. 2022 Link to this fact
Indoor air / Measured in people or real products
Nail salons serving 30 or more customers per day had significantly higher air d-limonene (median 6.18 ppb) than salons serving fewer than 30 customers (median 2.30 ppb, p=0.044), consistent with more frequent cleaning of tables between customers.
Moderate evidence: Single small pilot study; cleaning-product use itself was not directly measured or recorded, only inferred from customer volume and observed cleaning behavior.
Source: Han et al. 2022 Link to this fact
Indoor air / Other evidence
Ordinary spray-and-wipe cleaning with quats, bleach, hydrogen peroxide, or a thymol-based botanical disinfectant raised indoor fine-particle (PM2.5) levels by 0.7-14.5 micrograms per cubic meter and total-VOC sensor readings by 10-104 ppbv, measured across a residential bathroom, a university office, two chemistry labs, and a hotel in Canada.
Moderate evidence: Single study, small replicate counts per cleaner/location, and the TVOC sensor is explicitly non-quantitative.
Source: Souza 2025, ACS Earth Space Chem, ACS Earth and Space Chemistry Link to this fact
Indoor air / Other evidence
The lowest-ventilation room tested, a residential bathroom with an air change rate under 1 per hour, showed 146-346% higher cleaning-related PM2.5 increases and about 7-fold higher TVOC increases than a university office and lab with 5.9-9.1 air changes per hour, for the same cleaning products.
Moderate evidence: One bathroom, one office, two labs; not a dose-response series across many ACR values.
Source: Souza 2025, ACS Earth Space Chem, ACS Earth and Space Chemistry Link to this fact
Indoor air / Other evidence
The particulate matter released during cleaning in this study looked like direct, mechanical spray-bottle emission rather than new particles forming from chemical reactions in the air, consistent across all four very different cleaning chemistries tested.
Moderate evidence.
Caveats
No ozone was deliberately added or measured in these experiments, and none of the four products was a terpene-rich scented cleaner, so this does not rule out secondary particle formation under different (ozone-rich, terpene-rich) conditions documented elsewhere.
Source: Souza 2025, ACS Earth Space Chem, ACS Earth and Space Chemistry Link to this fact
Indoor air / Other evidence
Bleach cleaning produced a two-humped (bimodal) rise in total VOC readings, a pattern consistent with bleach's chlorine-based oxidants reacting with ordinary indoor VOCs to form new, oxidized compounds, rather than only releasing VOCs directly.
Moderate evidence: The oxidized compounds were not chemically identified in this study; the PID gives only a total, non-specific VOC signal, so this is an inferred mechanism, not a confirmed one.
Source: Souza 2025, ACS Earth Space Chem, ACS Earth and Space Chemistry Link to this fact
Indoor air / Other evidence
During real COVID-19 disinfection at a hotel, repeated use of a quats-based disinfectant raised fine-particle levels by 5.5 to 14.2 micrograms per cubic meter in the lobby, elevator, and a public bathroom, exposing cleaning staff to repeated particle bumps throughout a work shift.
Moderate evidence.
Caveats
One day of field measurement, one hotel; cleaning protocol there also deviated from the product label (solution left on surfaces rather than wiped off) to reduce staff vapor exposure.
Source: Souza 2025, ACS Earth Space Chem, ACS Earth and Space Chemistry Link to this fact
Indoor air / Other evidence
For 7 of 8 chemicals tracked in feminine hygiene products, a validated toxicokinetic model found that breathing ordinary indoor air contributed more to total monthly body burden than the feminine hygiene products themselves; the one exception was p-cymene, a common fragrance chemical, where product use was the dominant source.
Moderate evidence: Based on a small Michigan indoor-air sample (n=20) and a conservative worst-case dermal model; may not generalize to other regions or housing stocks.
Source: Lin 2025, Environmental Health Perspectives Link to this fact
Indoor air / Other evidence
In a 1989-era US EPA test house, a suit, skirt, and two blouses fresh from a dry cleaner (perchloroethylene solvent) put about 0.5 to 3 milligrams per cubic meter of the solvent into a closed closet on the first day, and about 60-190 micrograms per cubic meter into the adjoining bedroom.
Moderate evidence: One leased house kept closed, one cleaner, four runs with about 6-fold load-to-load spread; values read off bar charts are approximate; EPA-authored, no industry funding.
Source: Tichenor 1990, Atmospheric Environment. Part A. General Topics Link to this fact
Indoor air / Other evidence
The solvent from freshly dry-cleaned clothes was still detectable in the closet a week later (about 0.15-0.7 mg/m3 on day 7, approx.), and dropped to near or below the detection limit (1 microgram per cubic meter) only after the clothes were removed and the house was ventilated for days.
Moderate evidence: Single closed test house; the authors' closet was sealed with doors closed; approx., read from Fig. 3.
Source: Tichenor 1990, Atmospheric Environment. Part A. General Topics Link to this fact
Indoor air / Other evidence
In a room-sized test chamber with ozone at about 126 ppb, one spray of a lime-scented liquid air freshener released scent chemicals (mostly limonene) that reacted with the ozone and added about 200 micrograms per cubic meter of fine particles, up from a starting level of 13.
Moderate evidence.
Caveats
Single unreplicated chamber run (11 m3) with a generator-set ozone level and a direct spray; particle mass is calculated from particle counts, not weighed. Replicated by other chamber groups for the same mechanism, but this exact number is one run.
Source: Sarwar 2004, Journal of the Air & Waste Management Association Link to this fact
Indoor air / Other evidence
A pine-scented solid (hanging) air freshener in a chamber with about 112 ppb ozone added about 110 micrograms per cubic meter of fine particles, averaging about 81 over a 4-hour-plus run; with ozone at 3 ppb it added almost nothing.
Moderate evidence: One run per ozone level in an 11 m3 chamber; the authors link this to car fresheners hung from mirrors but did not test a vehicle.
Source: Sarwar 2004, Journal of the Air & Waste Management Association Link to this fact
Indoor air / Other evidence
The same scented products made far fewer new particles when ozone was low (3-15 ppb): added particle mass fell to 0.1-12 micrograms per cubic meter, though the liquid air freshener still made about 5.5 at 15 ppb.
Moderate evidence.
Caveats
Low- and high-ozone runs also differed in how much product was released (the liquid freshener released about a third as much in the low-ozone run) and in air exchange, so ozone is not isolated. Single runs.
Source: Sarwar 2004, Journal of the Air & Waste Management Association Link to this fact
Indoor air / Other evidence
A lemon-scented general-purpose cleaner, a wood floor cleaner, and a perfume sprayed into a chamber with 95-219 ppb ozone added about 16, 70, and 22 micrograms per cubic meter of fine particles, much less than the air fresheners.
Moderate evidence: Single chamber runs; the floor cleaner run used the highest ozone (219 ppb) so it is not comparable with the others; particle mass modeled from counts.
Source: Sarwar 2004, Journal of the Air & Waste Management Association Link to this fact
Indoor air / Other evidence
A 2011 Georgetown study that sent test fabrics through seven Northern Virginia dry cleaners found perchloroethylene (PCE) solvent still in polyester, wool, and cotton after one cleaning at all five shops that use PCE, about 10-57 nmol/cm2 depending on fabric and shop.
Moderate evidence.
Caveats
One jacket and one cleaning per shop, unpressed swatches sewn into the lining, seven shops in one region; residue measured, not what anyone breathes or absorbs. No industry funding stated.
Source: Sherlach 2011, Environmental Toxicology and Chemistry Link to this fact
Indoor air / Measured in people or real products
MI used as a paint preservative can reach people through the air: one quarter of MI-allergic patients with an identified source traced to paint, and the authors note people may be exposed unexpectedly in public spaces and shops.
Moderate evidence: Paint exposure was identified by case review and product data sheets, not air measurements in this paper; the airborne route rests on case reports cited by the authors.
Indoor air / Other evidence
In a 2001-2003 New York City study of 126 households, people living in buildings with a perchloroethylene dry cleaner had median indoor air of 27.5 micrograms per cubic meter, versus 2.3 in nearby buildings without one, and median adult blood levels of 0.15 versus 0.02 ng/mL.
Moderate evidence.
Caveats
One city, one study group; dry-cleaner buildings were deliberately selected from minority, low-income and complaint buildings, so this is not a city-wide average; one-day air samples; US EPA-funded, no industry link.
Source: Storm 2013, Environmental Research Link to this fact
Indoor air / Other evidence
Indoor air perchloroethylene was the dominant predictor of a person's blood and breath levels in dry-cleaner buildings; once air level was accounted for, age, sex, race/ethnicity, and income did not significantly predict them.
Moderate evidence: Regression in 74-79 people in dry-cleaner buildings only; one-day air sample versus blood drawn on average about 26 days later at a clinic.
Source: Storm 2013, Environmental Research Link to this fact
Indoor air / Other evidence
In the fragrance industry's 2015 aggregate exposure model, perfume, body spray, and deodorant spray were counted only as skin exposure; the paper reports no figure for how much is breathed in when a spray is used on the body.
Moderate evidence: Industry-funded paper by RIFM, Unilever, P&G, Givaudan and Firmenich staff; it shows the model did not estimate inhalation, not that inhalation is large or small.
Source: Safford et al. 2015, Regulatory Toxicology and Pharmacology Industry-funded Link to this fact
Indoor air / Review of other studies
Only four studies have ever measured how much perc is left in dry-cleaned clothes, and none looked at knitted outer garments, blended fabrics, or bedding, according to a 2016 review.
Moderate evidence.
Caveats
Secondary review funded by Australian Wool Innovation (wool industry body); 'systematic' is a self-label with no study counts or appraisal; relies on agency, trade and manufacturer sources. A narrative search (English only, searched 2013 and 2016); studies published since are not covered.
Source: Troynikov 2016, Journal of Environmental Management Industry-funded Link to this fact
Indoor air / Review of other studies
Perc vapor can seep through walls and ceilings into homes next to dry cleaners, and clothes that come out of the machine under-dried can expose customers, a 2016 review notes.
Moderate evidence.
Caveats
Secondary review funded by Australian Wool Innovation (wool industry body); 'systematic' is a self-label with no study counts or appraisal; relies on agency, trade and manufacturer sources. Mechanism statement from secondary sources; no levels given in this review. Measured home levels are in the Storm 2013 and Chao 1998 pages.
Source: Troynikov 2016, Journal of Environmental Management Industry-funded Link to this fact
Indoor air / Measured in people or real products
In four Polish spa salons, air sampled after aromatherapy massages exceeded the 300 µg/m³ indoor TVOC target in nearly every case, and one salon reached about 23,700 µg/m³ after a single massage.
Moderate evidence: 60 grab samples in four salons, one season; the 300 µg/m³ figure is a comfort target, not a health limit; the peak was a single instantaneous sample, not an 8-hour average.
Source: Pytel 2021, Environmental Science and Pollution Research Link to this fact
Indoor air / Measured in people or real products
In those spa salons, terpenes made up about 22% to 86% of the airborne VOC total on the days charted, and limonene was the most abundant terpene in all four.
Moderate evidence: Range from one example day per salon (Fig. 3), not all 60 samples; non-limonene VOCs are toluene-equivalent estimates.
Source: Pytel 2021, Environmental Science and Pollution Research Link to this fact
Indoor air / Measured in people or real products
What fills a treatment room's air depends on the oils used: limonene-rich oils such as orange or grapefruit gave limonene-dominated air, while rose oil gave none.
Moderate evidence: Few days per salon, oil mixtures often unknown or blended with additives; association by day, not controlled comparison.
Source: Pytel 2021, Environmental Science and Pollution Research Link to this fact
Indoor air / Other evidence
Spraying a trigger-type car air freshener for about a minute made a burst of fine particles in a parked SUV: particle counts at the driver seat rose from about 14,100 to as high as about 23,600 per cubic centimeter, and most of the particles were smaller than 100 nanometers.
Moderate evidence.
Caveats
One lab, three repeats, three unnamed sprays and three SUVs, stationary and engine off; particle chemistry, instrument size limits and health effects not reported, and no unsprayed control is described.
Source: Lee 2024, Science of The Total Environment Link to this fact
Indoor air / Other evidence
The same car sprays raised limonene, ethyl acetate, and cyclohexane in the cabin air; limonene at the driver seat in one medium SUV rose from about 10 to about 125 micrograms per cubic meter (about 165 with another spray).
Moderate evidence.
Caveats
Single small lab study; limonene values are read from a chart, so they are approximate; the small SUV had a much higher unexplained limonene baseline (about 280 micrograms per cubic meter before spraying, read from Fig. 5b3).
Source: Lee 2024, Science of The Total Environment Link to this fact
Indoor air / Self-reported survey
About 1 in 9 US adults (10.9%) said the scent of laundry products, fabric softeners, or dryer sheets vented outside irritates them (2005-06 survey; asked in the second survey only).
Moderate evidence: Self-report from a single survey; 'irritation' is not defined further and no exposure was measured.
Source: Caress & Steinemann 2009, Journal of Environmental Health Link to this fact
Indoor air / Other evidence
The EU's cosmetics committee could not assess the risk of inhaling dust from powder hair dye containing sodium perborate, because no particle-size data on the powder were available (particles under about 15 micrometers are inhalable).
Moderate evidence: A stated data gap, not evidence of harm; applies to the 2010 applicant's powder formulation.
Source: SCCS 2010 (SCCS/1345/10), SCCS opinion SCCS/1345/10 (PDF) Link to this fact
Indoor air / Other evidence
The CIR draft applies its 'most spray droplets are not respirable' reasoning to polysorbate sprays at up to 4%, while admitting some evidence that deodorant sprays release substantially larger respirable fractions and that the information is 'not sufficient'.
Moderate evidence: Inhalation data are thin (one ethoxylated sorbitan laurate rat LC50); same boilerplate challenged in the CIR 2024 respiratory draft.
Source: CIR 2015 draft Industry-funded Link to this fact
Indoor air / Animal study
The CIR draft applies the 'droplets over 10 micrometers are not respirable' argument to a 4% hydrogen peroxide aerosol hair spray while acknowledging propellant sprays release more small droplets than pump sprays.
Moderate evidence: Does not say whether the 4% hair spray is a propellant spray; CIR's own later 2024 draft qualifies this boilerplate for propellant sprays; industry-funded panel.
Source: CIR 2018 draft (Do Not Cite or Quote; PCPC-funded CIR) Industry-funded Link to this fact
Indoor air / Other evidence
In New York State data relayed by the county, homes with a perchloroethylene dry cleaner in the same building had indoor air at the 25th percentile of 215-269 micrograms per cubic meter and the 75th percentile of 700-735, far above the 4 (cancer), 30 (NYSDOH) and 40 (EPA reference) benchmarks.
Moderate evidence: Secondary relay of a 2010 NYSDOH survey whose sampling design is not described here; a later NYC study (Storm 2013) measured a median of only 27.5 in dry-cleaner buildings.
Source: SCDHS 2018 Link to this fact
Indoor air / Other evidence
Ordinary New York and New Jersey homes had indoor perchloroethylene far below co-located residences: median 0.34 and 95th percentile 3.9 micrograms per cubic meter in fuel-oil-heated NY homes, and 95th percentile 4.39 in New Jersey homes (detected in 23 of 100), about at the 4 microgram one-in-a-million cancer-risk level.
Moderate evidence: Relayed from the original surveys; the cancer benchmark is a lifetime-average value, so a 95th-percentile reading does not itself show excess cancer.
Source: SCDHS 2018 Link to this fact
Indoor air / Government agency
EPA's 2017 work plan adopts a new ADBAC inhalation endpoint (human equivalent concentration 0.018 mg/m3) bridged from a 28-day rat inhalation study of DDAC that found nasal ulceration and olfactory degeneration at 0.08 mg/m3, and waived an ADBAC-specific inhalation study.
Moderate evidence: A bridged endpoint from a related quat in rats, not ADBAC data; the endpoint is a plan input, and no inhalation risk assessment is in the document.
Source: US EPA 2017 Link to this fact
Indoor air / Government agency
EPA says the only submitted humidifier inhalation study for ADBAC cannot be compared with its inhalation level of concern (limit of quantitation 0.026 mg/m3 versus 0.018 mg/m3; tested at 100 ppm versus the 510 ppm label maximum) and plans to require a new study with a limit of quantitation of 0.00018 mg/m3.
Moderate evidence: A planned data requirement, not a finding that humidifier exposure is unsafe.
Source: US EPA 2017 Link to this fact
Indoor air / Industry source
Secondhand tobacco smoke is mostly sidestream smoke from the burning tip (85-90%) plus exhaled smoke (10-15%), and filters and air-dilution holes cut the smoke a smoker inhales far more than the smoke released into the room.
Moderate evidence: Written by R.J. Reynolds scientists; yields come from one four-cigarette study; chapter is a compilation, not new measurement.
Source: Rodgman & Perfetti 2013 Industry-funded Link to this fact
Indoor air / Other evidence
In a four-cigarette comparison, sidestream smoke carried far more of the nitrosamine NDMA (597-735 ng per cigarette) than the smoke a smoker inhales (4.3-31.1 ng), and about 2 to 4 times more benzo[a]pyrene in filtered cigarettes.
Moderate evidence: Single study of four cigarettes, compiled by industry authors; the catechol row's unit is misprinted so it is not used.
Source: Rodgman & Perfetti 2013 Industry-funded Link to this fact
Indoor air / Self-reported survey
Living in a rural area was linked to higher urinary metabolites of benzyl and butyl phthalate in both Swedish mothers and children (about 2.6 times higher MBzP in rural children, unadjusted), and mother-reported PVC flooring or wall coverings was linked to higher MBzP in mothers only; these are not fragrance phthalates.
Moderate evidence: Area, education, PVC and well water are entangled; PVC was reported by the mother, not measured in dust.
Source: Larsson 2014, Environment International Link to this fact
Information, not medical advice. See also: myths we won’t tell you.