Burning scented candles in your home could cause worse pollution than standing next to a busy road.
New research has revealed that, in one instance, the candles created four times the safe levels of one particularly harmful pollutant.
The study, by King’s College London (KCL), looked into the ways people could cut down on pollution in their daily lives and asked six volunteers to detect levels of black carbon in their homes.
Black carbon is a type of PM2.5, a group of air pollutants that scientists are particularly worried about as it can travel deeply into lungs and cause harmful effects such as lung disease.
EU standards for PM2.5 state there should be no more than 25 micrograms per cubic metre of air (25 mcg/m³).
In the investigation, one of the women said she liked to relax by lighting a scented candle.
However, it pushed the average pollution level in her home up from 1.5 to 37mcg/m³, with a peak of 99mcg/m³.
Many scented candles are made from paraffin wax, which emits harmful particles, and the wicks can produce soot.
Andrew Grieves, senior air quality analyst at KCL, told Yahoo News UK: “While these figures weren’t surprising to me, they may shock the everyday person.
“It is also important to note that the monitor was right next to the candle and it was burning in an enclosed space, which is why we had such a high reading.
“Black carbon is just one type of pollution, by standing on the side of the road, you’re going to be breathing in not just black carbon but nitrogen dioxide, sulphates and other things.”
“I don’t want to be a killjoy and say people must stop using candles, this is just the data that we found.”
The average concentration of black carbon in London is 6.9 mcg/m³.
Studies by the WHO European Centre for Environment and Health found sufficient evidence that long-term exposure to black carbon led to increased risk of heart and/or lung related death.
In 2016, the Royal College of Physicians found that pollution causes 40,000 premature deaths a year.