Dec 11, 2025

Are Candles Bad for Indoor Air Quality? What the Research Actually Says

Candles are a cozy staple in so many homes — but if you’ve ever wondered “Are candles bad for indoor air quality?”, you’re not alone. With more people paying attention to clean living and non-toxic products, this question comes up a lot.

The short answer? Candles can affect indoor air quality — but how much depends on the candle, how it’s burned, and your space. Let’s break down what credible research actually says (no fear-mongering, just facts).

What Is Indoor Air Quality, Anyway?

Indoor air quality (IAQ) refers to the air inside your home and what’s floating around in it — things like dust, smoke, and gases called volatile organic compounds (VOCs). VOCs are emitted from many everyday items including cleaning products, paint, furniture, air fresheners, and yes, candles.²

According to the U.S. Environmental Protection Agency (EPA), indoor air pollution often comes from multiple sources combined, not just one product.³

Do Candles Release Pollutants?

Candles and VOCs

Research shows that burning candles — especially scented ones — can release small amounts of VOCs such as toluene and formaldehyde into the air.⁴ These compounds are also released when cooking, cleaning, or even using personal care products.

A well-known health risk assessment published in Regulatory Toxicology and Pharmacology found that under normal conditions of use, emissions from high quality scented candles do not pose a significant health risk for consumers.³

Health organizations like the Cleveland Clinic echo this, noting that occasional candle use in a ventilated space is unlikely to be harmful for most people.¹

What About Soot and Smoke?

Candles can also produce fine particulate matter, often visible as soot. This usually happens when:

The wick is too long
The flame flickers excessively
The candle is burned for too long at once

Studies show that proper wick trimming and controlled burns significantly reduce soot production.¹

Are Some Candles Worse Than Others?

Wax Type Matters (But It’s Not Everything)

Paraffin wax, which is petroleum-based, has been shown to produce more soot in some studies when poorly formulated.³
Plant-based waxes, like 100% soy wax, are renewable and tend to burn cleaner when properly wicked and tested.²

That said, researchers emphasize that overall candle quality and burn habits matter more than wax type alone.³

Fragrance Matters, Too

Fragrance — whether in candles, wax melts, or room and linen sprays — is another contributor to indoor air chemistry.

Recent research from the American Chemical Society found that scented wax melts (even without a flame) can produce indoor air particles when fragrance compounds react with ozone indoors.⁴

This doesn’t mean fragrance is “bad,” but it does reinforce the importance of:

Using fragrance products intentionally
Choosing phthalate-free fragrance oils
Ventilating your space

So… Are Candles Bad for Indoor Air Quality?

Here’s the balanced, research-backed takeaway:

Candles do contribute small amounts of VOCs and particles to indoor air.²³
Occasional use of well-made candles in ventilated spaces is unlikely to pose a major health risk for most people.¹³
Heavy use, poor ventilation, or strong sensitivities can increase irritation for some individuals.¹

In other words: it’s not about avoiding candles altogether — it’s about being intentional.

Who Should Be More Cautious With Candles?

You may want to limit candle use or be extra mindful if you:

Have asthma, allergies, or respiratory sensitivities¹
Experience headaches or nausea around strong scents
Live in a very small or poorly ventilated space

If you notice symptoms, experts recommend reducing exposure and improving ventilation.¹

How to Burn Candles More Safely (and Cleaner)

Most experts agree these habits make a real difference: You can also see our full candle care guide.

1. Trim Your Wick Every Time

Keeping the wick trimmed to about ¼ inch helps prevent excess soot and smoke.¹

2. Burn Candles for 2–4 Hours at a Time

This allows an even melt pool without overheating the candle or increasing emissions.¹

3. Ventilate Your Space

Crack a window or door when burning candles — especially in smaller rooms.¹³

4. Choose Better-Made Candles

Look for candles made with:

Plant-based waxes
Properly tested wicks
Phthalate-free fragrance oils
Transparent candle brands that explain their ingredients¹²

Candles vs. Other Indoor Pollution Sources

For perspective, the EPA notes that cooking (especially frying), gas stoves, fireplaces, and smoking indoors are much larger contributors to indoor air pollution than candles.⁵

Candles are just one piece of a much bigger indoor air puzzle.

How Vibe & Glo Approaches Indoor Air Quality

Vibe & Glo is a nurse-founded brand, and we believe in enjoying the glow without the guesswork. That’s why our candles are made with:

100% soy wax
Crackling wooden wicks
Phthalate-free fragrance oils
Small-batch burn testing for an even, controlled burn

We won’t claim candles “purify” your air — but we do obsess over the details that matter.

The Bottom Line

Candles aren’t the villain they’re sometimes made out to be.

Used mindfully, well-made candles can absolutely be part of a cozy, intentional home without significantly harming indoor air quality.¹³ The key is quality, moderation, and ventilation.

If you’re ready to enjoy the vibes with peace of mind, explore our clean-burning soy candles designed to glow beautifully without the unnecessary extras.

Sources

Cleveland Clinic — Worried If Candles Are Toxic?
https://health.clevelandclinic.org/are-candles-bad-for-you
U.S. Environmental Protection Agency (EPA) — Volatile Organic Compounds’ Impact on Indoor Air Quality
https://www.epa.gov/indoor-air-quality-iaq/volatile-organic-compounds-impact-indoor-air-quality
Petry, T., et al. (2014). Human health risk evaluation of selected VOC, SVOC and particulate emissions from scented candles. Regulatory Toxicology and Pharmacology.
https://pubmed.ncbi.nlm.nih.gov/24582651/
American Chemical Society (2025) — Scented Wax Melts May Not Be as Safe for Indoor Air as Initially Thought
https://www.acs.org/pressroom/presspacs/2025/february/scented-wax-melts-may-not-be-as-safe-for-indoor-air-as-initially-thought.html
U.S. Environmental Protection Agency (EPA) — Indoor Air Quality: What Are the Major Sources of Pollution?
https://www.epa.gov/indoor-air-quality-iaq/indoor-air-pollutants-and-sources