Danish researchers have found that the fires used for cooking and heat in Viking-era houses would have caused significant indoor air pollution.
Their article, ‘Household air pollution from wood burning in two reconstructed houses from the Danish Viking Age’ was published last year in the journal Indoor Air. Using experimental archaeology, they tested carbon mononxide, carbon dioxide and fine particulate matter at two Danish museum reconstructions of Viking Age ‘Hedeby House’ – the first at Moesgard Museum and the second at Bork Viking Harbour.
The reconstructions were based on a 9th-century house discovered in 1968 in the Viking Age city Hedeby, located near today’s Schleswig, Germany. The two reconstructed houses “had outer walls made of wattle and daub, tamped earth floors, and thatched roofs. Inner walls and doors were made from wood, except for some doorways which just had a curtain. The houses were divided into three rooms: a central living room, a side room facing west with household functions, and a room to the east with work space. The living room had an open fireplace and wide ridges along each side, which served as beds and storage areas. A wood-plank loft was located on each side of the room, above the ridges, at about 2 m height.”
During 13 winter weeks between 2011-12, the researchers took monitor environmental readings in the houses while a fire was kept:
On a typical day, the fire was lit around 7:30 am for cooking breakfast and then maintained for heating throughout the day. Lunch and dinner were also prepared on the fire. The pattern of use is reflected in the varying levels of combustion products in the air throughout the day, as well as in the consumption of wood.
The researchers discovered that those living in the home would have been exposed to a carbon monoxide level of 6.9 parts per million and a fine particulate matter exposure of 0.41 mg/m3, both of which are significantly higher than World Health Organization (WHO) maximum standards. Long term exposure to such poor air levels have been linked to medical problems such as chronic bronchitis, persistent headaches, memory loss and other ailments.
The design of the house and poor venting along the roof seem to have been responsible for keeping too much smoke from leaving the building. The researchers also note that the volunteers who stayed in the houses and tended to the fire did not have much experience with this task, and this may have contributed to the pollution levels.
The researchers conclude “that health conditions in the Viking Age were influenced by woodsmoke exposure. We have not in this study distinguished strongly between traditional sex role related work tasks for the participants, but just as is experienced by many women and children today, women and small children in the Viking Age probably received the highest exposures to woodsmoke.”
The article ‘Household air pollution from wood burning in two reconstructed houses from the Danish Viking Age’, by J. M. Christensen and M. Ryhl-Svendsen, appears in the journal Indoor Air. .
See also: Houses and domestic life in the Viking Age and medieval period: material perspectives from sagas and archaeology