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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.
Green, natural and unscented / Test-chamber measurement
The limonene given off by a natural fragrant plant is the same chemical as the limonene in cleaners and air fresheners; in this study three plants took room limonene to about 60-84 ug/m3 on average over 3 hours, in the range of a plug-in air freshener and well below the 1,000-6,000 ug/m3 seen right after terpene cleaning in a chamber.
Weak evidence: Cross-study comparison of different averaging times and rooms; the 'after' means are back-calculated from the dose table; plug-in and cleaning values come from other studies.
Information, not medical advice. See also: myths we won’t tell you.