Candle Conundrum: Do They Pollute Indoor Air?

Candles are a popular way to create a cosy atmosphere and fill your home with pleasant fragrances. However, they may be doing more harm than good. Research shows that candles can significantly impact indoor air quality by releasing various chemicals and pollutants. A Danish study found that candles were the number one source of indoor UFP pollution, contributing to 58% of the total pollution in homes. With people spending 85-90% of their time indoors and inhaling up to 20,000 litres of air daily, the potential risks of indoor air pollutants to our health cannot be ignored.

Scented candles emit more indoor air pollutants than unscented candles

While candles are a great way to create a pleasant ambience, wind down after a stressful day, or set the tone for a night of entertaining, they can also emit indoor air pollutants. According to experts, candles can impact indoor air quality, but the negative effects are generally small as long as the candles are burned in well-ventilated spaces.

Scented candles, in particular, have a greater impact on indoor air quality than unscented candles. This is because scented candles typically contain more volatile organic compounds (VOCs). These compounds are released into the air as the candle burns, potentially lowering the indoor air quality. The synthetic fragrances in scented candles can also create more soot than unscented varieties, further contributing to indoor air pollution.

The type of wax used in candles also makes a difference. Paraffin wax candles, for example, have been found to emit more pollutants than natural wax candles. This is because paraffin wax is derived from petroleum and can release carcinogenic chemicals such as benzene, toluene, formaldehyde, and acetaldehyde. Higher quality natural wax candles, such as those made from soy or beeswax, tend to burn cleaner and release fewer harmful chemicals.

To minimize the impact of candles on indoor air quality, it is recommended to choose unscented, fragrance-free, and uncolored candles made from highly-refined wax. Burning candles in moderation, ensuring proper ventilation, and following safety guidelines such as trimming the wick and avoiding drafts can also help reduce the potential negative effects of candle emissions.

It is worth noting that the overall effects of scented candles on indoor air quality are considered small under normal conditions. However, some individuals may be more sensitive to scents and specific pollutants, and therefore more affected by exposure. Additionally, the impact of candle burning habits may be more significant in larger numbers or in poorly ventilated spaces.

Paraffin wax candles emit more pollutants than natural wax candles

While candles are often enjoyed for their pleasant scents and calming ambiance, they can also be a source of indoor air pollution. The type of candle and the burning conditions can significantly impact the air quality. Paraffin wax candles, in particular, have been found to emit more pollutants than natural wax candles, such as those made from coconut, soy, or beeswax.

Paraffin wax, derived from petroleum or crude oil, releases toxins during combustion. These toxins include volatile organic compounds (VOCs) and chemicals like toluene, a benzene derivative and known carcinogen. The combustion process of paraffin candles produces particulate matter and carbon emissions, contributing to indoor and outdoor air pollution. Additionally, paraffin wax is not biodegradable and is obtained from non-renewable resources, further impacting the environment.

On the other hand, natural wax candles offer a cleaner and safer burn. For example, soy wax candles have been found to emit little to no harmful chemicals and produce less soot than paraffin wax candles. Coconut wax candles are also a clean-burning alternative, free of harmful toxins. Natural waxes are biodegradable and made from renewable resources, reducing their environmental footprint.

The wick type is another important consideration when choosing candles. According to HVAC expert Jessica Wicks, "candle safety really comes down to the wick being used and the ingredients of the candle." Natural wicks made from wood or cotton can be a healthier option than metal or zinc wicks, which may contain toxins.

To minimize the impact of candles on indoor air quality, it is recommended to burn candles in moderation and ensure proper ventilation in the space. By being mindful of the type of candle, wick, and burning conditions, individuals can enjoy their candles while maintaining a healthier and more sustainable environment.

Candles are the number one cause of indoor air pollution in Denmark

While candles can make our houses smell good and help us relax, they can also negatively impact indoor air quality. A Danish study found that candles are the number one cause of indoor air pollution in Denmark.

The study, conducted by Danish scientists, aimed to measure the air quality in city apartments near busy streets. The results showed that candles contributed to 58% of the total indoor UFP pollution in the homes studied. In comparison, nearby roads only contributed 3% of UFP pollution. The indoor air quality in these Danish homes was comparable to that of Beijing, but the sources of pollution were almost opposite. While 70% of UFP pollution in Beijing came from outdoor sources, the Danish homes' indoor sources, primarily candles and cooking, accounted for more than 80% of the worst kind of indoor air pollution.

Candles, especially scented ones, can emit various chemicals and volatile organic compounds (VOCs) that can lower indoor air quality. These chemicals are slowly released into the air, even when the candles are not lit, and can include toxic or hazardous substances such as formaldehyde, acetaldehyde, and free radicals. The smoke and soot produced by burning candles can also contribute to indoor air pollution, similar to tobacco smoke and wood smoke.

The type of candle also matters. Paraffin wax candles, for example, have been found to emit more pollutants than natural wax candles. The wick type is another important factor in candle safety. While candles can impact indoor air quality, experts suggest that burning them in moderation and in well-ventilated spaces can mitigate these negative effects.

The findings of the Danish study are not unique to Denmark. Household conditions in most of Europe and the United States are similar, so the implications of candle burning for indoor air pollution are relevant across these regions. As people in high- and middle-income countries spend a significant amount of time indoors, the potential health risks associated with indoor air pollutants cannot be overlooked.

Candles, diffusers, room sprays, and gels all lower indoor air quality

Candles, diffusers, room sprays, and gels can all lower indoor air quality. While candles can make our houses smell good and create a calming ambiance, they also come with various indoor air pollutants. According to a Danish study, burning candles contributed to 58% of the total indoor UFP pollution in 28 out of 56 homes.

Scented candles, in particular, have a greater impact on air quality than unscented candles due to the higher number of volatile organic compounds they contain. Paraffin wax candles emit more pollutants than natural wax candles, and the type of wick can also make a difference. The chemicals used in scented candles are released at a faster rate when burned, but they are also slowly released into the air when the candle is not lit. These chemicals can include toxic pollutants such as formaldehyde, acetaldehyde and free radicals, which are classified as toxic or hazardous by agencies like the EPA.

Essential oil diffusers, reed diffusers, and steam diffusers are alternatives to candles that do not release smoke. However, diffusers, room sprays, and gels are also designed to give off fragrances and can emit chemicals that negatively impact indoor air quality. Air fresheners, for example, can emit more than 100 different chemicals, including volatile organic compounds, and there is no legal requirement for the disclosure of these chemicals.

Therefore, it is advisable to use scented candles and similar products in moderation and ensure proper ventilation when burning candles to minimize their impact on indoor air quality.

The chemicals in candles are released into the air whether they are burned or not

Candles are a source of indoor air pollution. When burned, they release hydrocarbons, specifically chemical compounds consisting of hydrogen and carbon, into the air. The combustion process involves the flame heating the nearby air, which causes it to rise. Cooler air and oxygen then rush in at the bottom of the flame to replace the warm air. This creates a continuous cycle of upward-moving air, known as a convection current, which gives the flame its characteristic teardrop shape. The heat of the flame also vaporizes the liquid wax, breaking down the hydrocarbons into molecules of hydrogen and carbon. These vaporized molecules react with oxygen from the air to produce heat, light, water vapour, and carbon dioxide.

However, if the flame receives too little or too much air or fuel, it can flicker or flare, and unburned carbon particles (soot) may escape from the flame before they can fully combust. This incomplete combustion can result in the release of trace amounts of toluene and benzene. Toluene exposure, without proper ventilation, can irritate the eyes, nose, throat, and skin, as well as lead to headaches, dizziness, confusion, and anxiety. Benzene, a gas associated with forest fires, volcanoes, and burning coal or oil, is primarily used in industrial and pharmaceutical settings.

The impact of candles on indoor air quality varies depending on several factors. Scented candles, for instance, typically contain more volatile organic compounds (VOCs) and have a greater impact on air quality. Paraffin wax candles are also found to emit more pollutants than natural wax candles. The quality of the candle plays a role, with lower-quality candles emitting more particulate matter and chemicals. Additionally, the number of candles burned and the ventilation of the space are important factors. Burning a larger number of candles or burning candles in poorly ventilated spaces can significantly affect air quality.

While candles do release chemicals into the air when burned, it's important to note that the overall impact on air quality is generally considered small under normal conditions. The negative effects are usually minor as long as candles are burned in well-ventilated spaces and in moderation. However, individuals with asthma, allergies, or chronic lung conditions may be more susceptible to the effects of indoor air pollutants. Therefore, it is advisable to be mindful of candle usage and to prioritize high-quality candles and proper ventilation to minimize any potential risks.

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