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 / Review of other studies
During ordinary house cleaning with bleach, chlorine gas concentrations can peak at up to about 0.5 parts per million, and trichloramine is thought to reach similar concentrations when bleach reacts with ammonia or other nitrogen-containing substances.
Weak evidence: This is the authors citing a separate domestic-cleaner cohort study (their own ref. 15) as background, not a measurement made on the children or homes in this study.
Source: Nickmilder, Carbonnelle & Bernard 2007, Pediatric Allergy and Immunology Link to this fact
Indoor air / Other evidence
In a 1996 Hong Kong pilot, five freshly dry-cleaned garments stored in a poorly ventilated, carpeted bedroom wardrobe pushed bedroom perchloroethylene (PCE) to 494 micrograms per cubic meter on the first day, against outdoor readings below about 1 microgram.
Weak evidence.
Caveats
One bedroom per ventilation condition (3 total), no randomization, 24-h tube samples; ventilation not measured during the tests; government-commissioned (no industry funding); not children or health outcomes.
Source: Chao 1998, Building and Environment Link to this fact
Indoor air / Other evidence
Hot, dry car cabins shift the particles from a spray smaller: at 25 degrees C the driver-seat nanoparticle share reached about 81% (versus about 65% at 10-20 degrees C).
Weak evidence: Single SUV and spray; the humidity explanation is the authors' interpretation; text and abstract disagree on the size of the rise (25.3 +/- 0.4% vs +/- 3.2%).
Source: Lee 2024, Science of The Total Environment Link to this fact
Indoor air / Other evidence
EPA's 2006 assessment found modeled inhalation margins for home mopping, wiping, trigger spray, aerosol deodorizer and carpet spray at 820 to 50,000 against a target of 100.
Weak evidence: Modeled with surrogate exposure data, an oral rabbit study as the inhalation endpoint, and judgment-based amounts handled; EPA itself called for confirmatory exposure data.
Source: EPA RED 2006 Link to this fact
Indoor air / Other evidence
The county quotes dry-cleaned-wool scenarios of perchloroethylene up to 240 milligrams per cubic meter in a sealed 3.4 m3 closet and 620 in a warm car, assuming all residual solvent vaporizes.
Weak evidence.
Caveats
Theoretical ceilings with no ventilation; the figures differ from the ppm values on our Sherlach 2011 page (about 50 and 126 ppm, roughly 340 and 850 mg/m3), so they are not reconciled; not measured exposure.
Source: SCDHS 2018 Link to this fact
Information, not medical advice. See also: myths we won’t tell you.