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.
Fragrance is everywhere / Measured in people or real products
Even in Perth, a city with very clean outdoor air, limonene and pinene (scent chemicals typical of citrus- and pine-scented cleaners and air fresheners) were found in 80-100% of homes when a sensitive test was used.
Strong evidence: Low concentrations (median ~1.5-2.4 µg/m³); sources not measured; 64 weekday-daytime visits.
Source: Maisey 2013, Atmospheric Environment Link to this fact
Fragrance is everywhere / Measured in people or real products
In EPA's large 1980s studies of US homes, limonene, the chemical behind lemon scents, was the airborne chemical with the highest average concentration in people's homes.
Strong evidence: 1980-87 TEAM data; no health risk estimated for limonene.
Source: Wallace 1991, Environmental Health Perspectives Link to this fact
Fragrance is everywhere / Measured in people or real products
Scientists can identify which everyday products are polluting a city's outdoor air just by measuring a handful of specific chemical fingerprints: a silicone compound (D5-siloxane) for personal-care products and citrus/pine-scent chemicals (monoterpenes, mostly limonene) for fragranced products, confirmed by mobile-lab measurements across New York City, Pittsburgh, Chicago, and Denver.
Strong evidence: Outdoor air only; four US cities, no LA data; tracer status is based on population-density correlation and inventory apportionment, not a direct source test.
Source: Gkatzelis 2021, Environmental Science & Technology Link to this fact
Information, not medical advice. See also: myths we won’t tell you.