Their response is to fire up their home heating. For many, this means a wood or coal burning fire. With little wind to disperse the coarse particles emitted from home fires, smog builds up under the inversion layer. In summer, it's windier and winds tend to blow pollution away. In 1997, there were approximately 15,500 open fires, 3,500 closed coal burners and 31,000 wood burners in the city. In the 1990s the number of high pollution nights per year averaged 30; in 1999 it peaked at 60; in 2018 there were 3. Historical work In the 1980s, Holm returned to the University of Canterbury to complete a master's degree in history; she wrote her thesis on her grandfather George and his six siblings, and later published the research as a book, Nothing but Grass and Wind. She was also a keen genealogist and travelled the country visiting cemeteries and photographing headstones. The Canterbury History Foundation awarded Holm the 2005 A. C. Rhodes Memorial Award in recognition of this work. In the same year, she published her book on the lives of early surveyors, and became the first woman appointed an honorary member of the New Zealand Institute of Surveyors. Publications Air Pollution. Christchurch: Epicentre, 1989. Nothing but Grass and Wind: The Rutherfords of Canterbury. Christchurch: Hazard Press, 1992. Caught Mapping: The Life and Times of New Zealand's Early Surveyors. Christchurch: Hazard Press, 2005. On Zealand's Hills, Where Tigers Steal Along. Wellington: Steele Roberts, 2008. Legacy Following Holm's death in 2018, her family established the Janet Holm Prize in History in her memory at the University of Canterbury. The inaugural award of the prize was made in December 2018. References 1923 births 2018 deaths People educated at Rangi Ruru Girls' School University of Canterbury alumni Writers from Christchurch Victoria University of Wellington alumni New Zealand environmentalists New Zealand Members of the Order of the British Empire New Zealand women historians New Zealand genealogists Air pollution in New Zealand 20th-century New Zealand historians 21st-century New Zealand historians