Burning a scented candle to fill the room with the scent of gingerbread, cinnamon and pine may get you in the Christmas spirit, but it can be harmful to your health.
Research has shown that burning candles has a significant effect on indoor air quality – and can be worse for your lungs than breathing in passive smoke.
This is because candles produce a complex mix of chemicals and particulate matter, including toxic gases, when burned such as carbon monoxide, sulfur dioxide and nitrogen oxides.
Products such as scented candles and incense sticks can also produce volatile organic compounds (VOCs).
Together, inhaling these substances can cause coughing, sneezing and eye irritation and worsen asthma symptoms.
But in the long term, this indoor pollution can also increase the risk of heart disease, lung cancer and chronic bronchitis, wrote Dr Asit Kumar Mishra of University College Cork and Dr Marie Coggins of the University of Galway. The conversation.
Burning scented candles can cause concentrations of fine particles – which can cause lung damage when inhaled – to rise to fifteen times the limits prescribed by the World Health Organization.
The studypublished in the journal Indoor Environments, measured the air quality of 14 homes in Galway, Ireland, both 24 hours before and 24 hours after making changes to improve the home’s energy efficiency.
Burning scented candles produces a complex mix of chemicals and particulate matter, including toxic gases such as carbon monoxide, sulfur dioxide and nitrogen oxides
In each home, researchers measured the concentrations of five pollutants, including CO2 and pollutant particles smaller than 2.5 micrometers, known as PM2.5, which can easily enter the lungs, as well as the temperature and humidity in two rooms.
PM2.5 are soot particles in the air that are invisible to the human eye and can enter the blood and penetrate deep into the lungs. They can be emitted from vehicle engines, wood burning and smoking.
In each room, scientists placed devices that measure pollution one meter away from the floor and sources of pollution and ventilation (such as windows and vents).
During this time, residents were asked to document typical household activities and their heating and ventilation methods, such as cooking, opening windows, burning candles, and cleaning.
The results showed that activities such as burning candles, smoking and blocking wall vents can be harmful to indoor air quality, increasing levels of PM2.5 and CO2.
PM2.5 particles are believed to cause inflammation in the lungs that can activate dormant, harmful cells, leading to cancer-causing genetic mutations.
The International Agency for Research on Cancer (IARC) designated particulate matter PM 2.5 as a Group 1 carcinogen in 2013, due to evidence linking the pollutant to lung cancer.
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The study also found that when equal weights of cigarettes and incense sticks are burned, the incense sticks produce about four times as much particulate matter as the cigarettes.
In non-smoking households, a candle can be the main source of pollution, releasing ultra-fine particles into the air, with a flickering flame producing more larger particles and increasing black carbon emissions.
Burning scented candles in small bathrooms or bedrooms exposes residents to a higher concentration of pollutants, the study shows.
In poorly ventilated areas, researchers found that higher concentrations of pollutants such as formaldehyde – a colorless, strong-smelling chemical – were present at levels that can cause upper respiratory tract irritation.
Scented candles can be even worse for our health and can produce more fine particles than unscented candles.
But according to Dr. Mishra and Dr. Coggins, it’s almost impossible to know what chemicals you’re releasing into your home when burning a scented candle, since only 10 percent of the ingredients are listed on the package.
That’s because scented candle manufacturers in the US and EU are not required to disclose all the substances used in their products.
Nitrogen oxides – which are also emitted by cars – are the main pollutant produced by scented candles and can damage the lungs and airways.
Even some of the organic compounds emitted by home fragrance products, such as benzene, phthalates and formaldehyde, can cause cancer, according to the researchers. American Lung Association.
Short-term exposure to these pollutants has been shown to reduce cognitive function, while chronic exposure to frankincense smoke has also been linked to a decline in cognitive function, according to a 2020 study published in the journal Nature.
Researchers also warn that choosing candles made with natural ingredients may not protect you from harmful effects.
Some of the natural chemicals emitted can react with ozone in room air, creating potentially toxic byproducts.
Burning candles in a larger room with open windows can help reduce the harmful effects, the experts advised – but they added that more research is needed to understand the full health risks.