It also absorbs potentially harmful pollutants in the air and provides food and shelter for birds and insects.

It cites evidence that the vapour contains harmful pollutants.

There are concerns over the health impacts of diesel, which emits far higher levels of harmful pollutants, including nitrogen oxides and particu-lates.

Health experts have warned that the foggy weather stops harmful pollutants, known as particulate matter, dispersing and can cause harm to individuals with asthma and lung disease.

Harmful pollutants to the health and the environment include particulates (soot), hydrocarbons, carbon monoxide, ozone, lead, and various oxides of nitrogen.