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
The authors judged that the PCE from dry-cleaned clothing is not itself a major health concern in Hong Kong because most households dry-clean rarely and ventilate, but high levels can occur in poorly ventilated homes with frequent dry cleaning.
Weak evidence.
Caveats
Authors' judgment from 3 rooms and a 500-household phone survey (64.6% dry-clean; 5% every 2-3 days, 34% every few months, 39% yearly); their own tables show some days above the CARB benchmark at all three sites.
Source: Chao 1998, Building and Environment Link to this fact
Indoor air / Other evidence
Wool dry cleaned repeatedly at the same shop kept absorbing more PCE with each cycle (about 47 nmol/cm2 after one cleaning to about 195 after six, read from Fig. 5), while cotton and polyester leveled off.
Weak evidence: One shop, one jacket, 1-6 cycles, replicate extractions not independent garments; values read from a chart.
Source: Sherlach 2011, Environmental Toxicology and Chemistry Link to this fact
Indoor air / Other evidence
OSHA says concentrations of many VOCs are consistently higher indoors, 'up to ten times higher', than outdoors, and lists cleaning supplies and pesticides among the thousands of product sources.
Weak evidence: A blanket multiplier with no data in the booklet; EPA pages say 2 to 5 times; primary data show compound-specific ratios from about 1 to about 60.
Source: OSHA 3430-04, 2011 Link to this fact
Indoor air / Other evidence
Someone doing their own house cleaning in a region with moderate outdoor ozone was estimated to inhale about 20 micrograms a day of formaldehyde and 35 micrograms a day of new particles from ozone reacting with cleaning-product and air-freshener ingredients.
Weak evidence.
Caveats
A modeled estimate borrowed from another review, not a measurement, for cleaning products and air fresheners together, not for perfume. It adds to formaldehyde and particles from other sources.
Source: Weschler 2006, Environmental Health Perspectives Link to this fact
Indoor air / Other evidence
Two products in the same category can behave very differently: with seed particles present, one deodorant turned about 17% of its evaporated mass into aerosol and the other about 6% (about, read from Fig. 2), and the two cleaning liquids ran about 5% and 12%.
Weak evidence: Approximate values read from Fig. 2; two products per category; the authors say the products are not representative of the market.
Information, not medical advice. See also: myths we won’t tell you.