The result of the screening points in a clear direction: If one can smell smoke from the neighbor’s stove, the level of polluting particles in the air is probably so high that it can be harmful to health.
Kåre Press-Kristensen, an engineer and senior adviser specializing in air quality from the Council for Green Transformation, which is an independent environmental organization, explains this.
– Our screening has shown that in new houses with mechanical ventilation, very high concentrations of carcinogenic, harmful smoke from the neighbors’ wood stoves can occur, he says.
Mechanical ventilation is usually installed in houses built within the last 20 years. The ventilation must ensure a good indoor climate, but can therefore have the opposite effect if the smoke outside is polluted.
Mechanical ventilation is also found in older houses that have been energy renovated with improved insulation and a new ventilation system.
The screening of the selected detached house in Copenhagen was made one evening from 19.30 to 20.30. Here, surprisingly high levels of harmful particles in the air were measured, says Kåre Press-Kristensen.
The villa is from 2011 and is located in a neighborhood where the houses are primarily heated by district heating. The house next door, however, has a wood burning stove.
And when the wind is in a certain direction, the smoke from the neighbor’s wood-burning stove is sucked straight into the living room and bedrooms of the family in question.
– When there is a smell of smoke indoors, the level of the harmful, ultrafine particles in the home is higher than on HC Andersens Boulevard during rush hour, says Kåre Press-Kristensen.
The number of ultrafine particles in the air sucked into the house by the mechanical ventilation was measured to be between 20,000 and 70,000 particles per cubic centimeter.
In comparison, there are approximately 25,000 ultrafine particles per cubic centimeter on HC Andersens Boulevard during rush hour on a weekday.
The boulevard is one of Copenhagen’s busiest roads.
– I had not imagined that one would be able to measure such high levels of harmful particles in a detached house, says Kåre Press-Kristensen.
He emphasizes that this is an initial screening, which must be followed up by more thorough investigations of air pollution in Danish houses.
The Council for Green Transformation sees several possibilities for limiting the pollution from wood smoke in houses with automatic ventilation.
On the one hand, the use of a wood-burning stove within a radius of 100 meters from homes with mechanical ventilation should be banned, the organization believes.
On the one hand, more efficient filters must be developed for the ventilation systems, so that more harmful particles are captured.