Graywolf knows everything...
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[I ran into this thismornin'...]
A fragrant candle may help you unwind and de-stress. But burning those containing a chemical called
limonene, often used for citrus-scented candles, as well as many cleaning products, can produce fumes that are downright unhealthy.
Recent British research found that households with a high levels of
limonene correlated with high levels of formaldehyde, which irritates the eyes and throat and may lead to nose and throat cancers.
Limonene reacts with gases in the air to create formaldehyde.
http://www.bbc.co.uk/programmes/articles/58KFJzpJb2kyLtDPhhHqnbQ/are-perfumed-products-bad-for-me
[excripts]
At the start of the experiment all the houses had similar levels of most chemicals - except the ones from fragrance. 3 of the 6 households had the highest levels of
limonene, which corresponded to the amount of household products and scented candles they used.
Importantly we also found that levels of formaldehyde correlated with the levels of
limonene.
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There is a small body of research suggesting that houseplants could possibly have powerful chemical-absorbing properties. One of the key papers was even published by NASA in the 1980s to investigate how levels of chemicals in enclosed space stations could be reduced.
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But that’s not the end of the story.
Since
limonene reacts in the air to make formaldehyde, you would expect the formaldehyde to rise as well.
But levels of formaldehyde actually fell in all three of the homes we measured (in contrast to the rising
limonene), while the plants were in there.
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[says nothing about smoking/vaping]...