Scented candles are a favourite at this time of year and chances are you've either been given one for Christmas or been in a home where their flickering glow has been accompanied by an aromatic whiff.

But be warned. In March, a team of experts tested six scented candles and identified they gave off a host of potentially dangerous industrial chemicals including formaldehyde and VOCs known to raise the risk of respiratory problems and cancer.

The study also warned that you don't even need to light them as simple evaporation enables the candles to pollute your home.

Other studies have shown that the chemicals are capable of being absorbed by the body simply through touch.

Another hazard lies in the fact that most scented candles are made with paraffin. When lit, the oil by-product gives off ultra-fine soot particles containing acetone, benzene and toluene, usually seen in diesel emissions, and known to be hazardous for asthma.

Those with asthma, COPD or chemical sensitivity may already have made a connection between exposure to scented candles and a worsening of symptoms.

The authors of the study conclude: "Scented candles can be significant sources of volatile chemicals in the indoor environment".

So the message would seem to be - ditch the scented candles altogether or find natural alternatives made of beeswax or soy with non-synthetic aromatics.