Are Candles Bad for Indoor Air Quality?

Once a simple, archaic light source, candles have become fundamental additions to many modern homes. They provide a warm shift in ambience and decorate our tables, shelves, and mantlepieces. However, recent studies have revealed shadows behind the wax light, posing questions such as: 'Are candles contributing to indoor air pollution?'

The answer isn't quite as simple and is much more nuanced than a yes or no.

How harmful a candle is can depend on several compositional factors, including wax type and the chemicals used to create synthetic fragrances. In this blog, the air quality experts at Ultra Protect will explore the research and potential risks associated with candle usage.

Are Some Candles Worse Than Others?

While some candles are safer than others, certain waxes should be avoided altogether. Paraffin, derived from petroleum, releases the same carcinogenic chemicals as diesel. These cancer-causing volatile compounds include formaldehyde and benzene. Studies performed by the Environmental Protection Agency discovered that burning candles made from paraffin wax contributes to much higher levels of indoor air pollution.

Scented candles often contain phthalates, a group of endocrine-damaging chemicals inimical to the reproductive, neurological, and developmental systems. Children are especially susceptible to phthalates' harmful nature, which can adversely affect their overall development.

Though reactions may vary depending on the individual, candles made with synthetic fragrances can also cause allergic reactions, from rashes to anaphylaxis.

However, it's important to note that not all candles are equally toxic. Less harmful waxes, such as beeswax and soy, are safer options, though they can also negatively affect indoor air quality from the combustion perspective. Often marketed as the 'healthier' option, beeswax may, in fact, improve air quality by neutralising airborne pollutants.

How Do Candles Affect Respiratory Health?

When discussing candles and indoor air quality, the effects on respiratory health are most certainly worth mentioning. Like any combustible material, when lit, candles release toxic fumes and ultrafine particulate pollutants into the surrounding atmosphere.

Candles also release soot, which can stain surfaces, including ceilings and furniture, and contaminate dated ventilation systems.

What Are Ultrafine Particles?

A study conducted in Denmark found that burning a candle for over two hours contributed to two-thirds of the total ultrafine particles. Unlike larger particles that our bodies can filter out, ultrafine particles can seep into the respiratory system and enter the bloodstream, leading to various health issues.

While occasional candle use is unlikely to affect respiratory health severely, constant exposure to ultrafine particles can compound a range of health concerns, especially for those diagnosed with preexisting ailments.

Symptomatic Reactions

Individuals with lung conditions like bronchitis or asthma may experience their symptoms worsening when inhaling volatile compounds and pollutants.

While they may not have any underlying respiratory conditions, some people are prone to lightheadedness and headaches when exposed to synthetically produced fragrances, with more serious cases leading to bouts of nausea.

Long-Term Risks

As with any pollutant—indoors or outdoors—long-term exposure, especially to high levels, can contribute to the manifestation of severe health conditions. Though more research is required, it is safer to assume that when misused over long periods, candles, most notably paraffin wax, can become detrimental to respiratory health.

Are There Alternatives & Practices for Safer Usage?

If you enjoy burning candles and want to minimise their effect on indoor air quality, several risk-reducing alternatives and practices exist for safe usage. Here are three that can make the most notable difference.

LED Candles

Enhancing the ambience of your indoor space can be achieved without candles; instead, you can use LED candles that provide the same glow without any emissions.

Essential Oil Diffusers

Try using essential oil diffusers if the scented quality draws you to candles. Something to note: essential oils, though safer in terms of pollutants, are known to be harmful to pets.

Improve Ventilation

To reduce the effects and health risks associated with candle use, it would be advisable always to burn candles in well-ventilated spaces to mitigate pollutants from building up. Open windows and use air purifiers like HEPA filters to remove volatile compounds.

If you’re a business owner, perhaps of a candle boutique, Ultra Protect offers indoor air quality assessments to ensure the air your employees and customers breathe is as healthy as possible.

Are Candles as Bad as Other Indoor Pollutants?

While it's worth understanding the impact of candles, other indoor activities, such as cooking with processed oils and using cleaning products brimming with chemicals, also adversely affect indoor air quality.

If you live in an urbanised area suffering from high outdoor pollution, ensuring your indoor air quality is managed to a safer level might be a conscious concern. Though candles don't contribute as much as frying food in overly processed oils, limiting their use is a sure way to improve air quality inside your home.

Candles & Indoor Air Quality

So, are candles bad for indoor air quality? Well, the answer depends on the type of candle, how long you burn it, and how well-ventilated your home is.

This blog's aim isn't to discourage you from using candles but to ensure you make safe and informed decisions to safeguard your home and health. Be mindful of the candles you use, avoid paraffin and opt for beeswax, open windows or use air purifiers.

By making informed decisions, you can enjoy the warmth and ambience without ever compromising the air you breathe. For more information, contact our team and take your first breath towards cleaner, healthier air today.

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What is the Workplace Exposure Level for Dust? Understanding TWA and STEL

By Andy Potter • September 7, 2026

If you're responsible for health and safety in your workplace, you've probably encountered the terms "workplace exposure level," "TWA," and "STEL." But what do they actually mean, and why do they matter for dust management? The simple answer: these are legal limits set by the Health and Safety Executive (HSE) to protect workers from harmful dust exposure. If you're not monitoring them, you're flying blind and potentially breaking the law. What is Workplace Exposure Level? A workplace exposure level (WEL) is the maximum amount of a harmful substance that a worker can be exposed to during their working day without suffering adverse health effects. For dust, it's measured in milligrams per cubic metre of air (mg/m³). The HSE sets these limits based on scientific evidence about how different dust types affect human health. Different dusts have different exposure limits because they pose different risks. For example, the WEL for respirable crystalline silica is far stricter than for general inert dust, because silica is significantly more harmful to the lungs. Think of it this way: the WEL is your compliance baseline. If dust concentrations in your workplace stay below this limit, you're meeting your legal obligation. If they exceed it, you have a duty to investigate why and take corrective action. Download the HSEs guidance on workplace exposure limits If you want to understand the levels in your workplace contact us about our silica air sampling services TWA: The 8-Hour Average TWA stands for Time-Weighted Average, and it's the most commonly referenced exposure limit. The TWA measures the average concentration of a substance over a standard 8-hour working day. Here's why that matters: dust exposure isn't constant. Workers might face high concentrations during certain activities (cutting, grinding, demolition) and lower concentrations during others. The TWA accounts for these fluctuations by averaging them out over the full shift. This recognises that workers can tolerate brief periods of higher exposure, provided the average stays within acceptable limits. For example, the current WEL for respirable crystalline silica is 0.1 mg/m³ as an 8-hour TWA. This means that if a construction worker is grinding stone for part of their shift but doing lower-dust tasks for the rest, the daily average should not exceed this level. The advantage of TWA is that it's practical for real-world work. Few jobs maintain constant dust levels. The disadvantage is that it can mask dangerous peaks, if a worker is exposed to very high concentrations for a short period, the TWA might still look acceptable. STEL: The Short-Term Exposure Limit STEL stands for Short-Term Exposure Limit, and it's your safety net for peak exposures. A STEL is the maximum concentration a worker should experience during any 15-minute period in a working day, and no more than four such periods should occur, with at least 60 minutes between them. The STEL exists precisely because the TWA can obscure dangerous peaks. Imagine a worker exposed to very high silica dust for 15 minutes whilst cutting stone, then lower levels for the rest of the day. The TWA might be within limits, but those 15 minutes could still cause significant lung damage. There should be a maximum of 4 STEL's in a single working day and there must be at least 60-minutes between each STEL period. Not all dusts have a STEL, but those that do (like respirable crystalline silica) reflect a recognition that short, intense exposures carry genuine health risks that the 8-hour average doesn't capture. Reducing personal exposure to inhalable dust with Cleanspace Respirators

What Is Respirable Crystalline Silica Dust?

By Ultra Protect • September 7, 2026

Learn what respirable crystalline silica dust is, the symptoms, UK exposure limits, and how to test for it on site. A practical guide from Ultra Protect.