March 21st, 2014

Some inquires typically occur about this time of year regarding school playgrounds that have developed an odour.  This occurs during some spring thaws and is sometimes referred to as “Frost Boils.”  Yellow coloured ice and foul odours often occur in school grounds and playgrounds in late winter or early spring after rapid thawing or rainfall.  It is caused by an anaerobic (without oxygen) decomposition of the vegetation below the ice.

This process produces ammonia which gives the ice its yellow discolouration. As the ice breaks down, ammonia comes to the surface of the ice. The ammonia adheres to the children’s boots and outer clothing as they play on the ice. It is the ammonia that gives off the pungent odour in the school’s hallways where children store their outdoor clothing.

This condition is not a health hazard, but a phenomenon of nature and will probably last until the disappearance of ice and drying conditions. This phenomenon is not localized to this area and is occurring throughout the province.

If you have further questions, please contaact your local health department.