During long and cold nights, people often stay indoors and to warm the room, lighting a candle may brighten up the house. Perfumed products and scented candles though may contain cancer-causing substances, a new study suggests.
Researchers from BBC and Professor Alastair Lewis from the University of York analyzed the air quality inside six similar and modern houses for a range of volatile organic chemicals.
They found that the stand-out chemical was limonene, which is commonly found in candles and gives a citrus smell. It is found in the peels of citrus fruits and other plants. In some of the houses that used various cleaning products, limonene levels were increased.
Limonene is not a harmful chemical because it is widely used as flavoring for foods and chewing gum. It is also used to promote weight loss and prevent cancer. When used as perfumes in houses, however, it does not stay long as limonene.
When the researchers analyzed the reactivity of limonene, they found that when exposed to ozone, which is present even inside the house, limonene produces another type of chemical called formaldehyde, a carcinogenic substance.
Since the '80s, formaldehyde has been linked to cancer and in 2011, it was listed as a human carcinogenic. This chemical is found in furniture and is produced by burning cigarettes and gas stoves.
The researchers wanted to measure formaldehyde in the houses too, and they found that the amount of formaldehyde in these houses was correlated with limonene levels.
The research did not just measured the harmful chemicals in houses. They also wanted to somehow reduce the levels of these harmful substances through practical solutions so they placed houseplants in each house for six weeks. Prof. Lewis tracked the levels of both formaldehyde and limonene during the duration of the houseplants' stay in the houses.
After one month, the levels of limonene from air fresheners and scented candles increased perhaps due to the weather that required doors and windows to be constantly closed. The plants did not change the levels of limonene but the formaldehyde levels were significantly reduced. The outcome suggests that houseplants helped absorb harmful chemicals like formaldehyde.
Laboratory tests show that English Ivy is a good overall absorber in the house. For formaldehyde chemicals, lavender, geraniums and ferns are best for absorption.
Photo: Paul Wells | Flickr
