New Danish Research on Fine Particles from Candles Supports Candle Safety

Numerous media reports in recent years have suggested that candles are a major source of fine particulate indoor air pollution and may therefore pose a health risk. However, new research from the Danish Environmental Protection Agency (Miljøstyrelsen) challenges this assumption.

The primary goal of the study was to scientifically examine the number and composition of particles and other substances released during normal candle use. Popular candles available in Denmark were tested, and the study reached several key conclusions.

The results showed that candles do emit a relatively high number of fine particles when burned. However, when used as recommended—specifically when protected from drafts—virtually all of these particles are composed of salts used in wick treatment. These salts are water-soluble, meaning they are not persistent and can be readily eliminated by the body.

The study also found that soot levels in candle emissions are very low, especially when compared with sources such as diesel exhaust. In addition, no heavy metals, including lead or nickel, were detected in the emissions.

Emissions of volatile organic compounds (VOCs) were also found to be minimal and unremarkable.

Because of these differences, the particles produced by candles should not be directly compared with those generated by other combustion sources such as motor vehicle traffic.

The study recommends choosing high-quality candles, keeping them away from drafts during burning, and regularly trimming the wick to ensure optimal performance and cleaner combustion.

Source: National Candle Association (referencing findings from the Danish Environmental Protection Agency, Miljøstyrelsen).