Silt from earthquakes likely reason for increase in polluted days Christchurch

Dust particles from silt and damaged roads are likely to be responsible for an increase in the number of Christchurch’s high pollution nights this year.

Ken Taylor, Environment Canterbury director investigations and monitoring, says there have been 21 high pollution days to July 31 this year, compared with 12 in the same period last year.

However, of these 21, only nine are typical of other years. Twelve days are likely to be related to the February 22 and June 13 earthquakes. High particulate levels were recorded on days after those events especially in February, when there was a lot of windblown silt and debris.

“The numbers of high pollution days in the city each winter has been dropping – from 26 for the same time period in 2006, so ignoring the earthquake-related events, this trend is still continuing,’’ he says.

While many chimneys across Christchurch have come down, it was too early to tell if there has been a decrease in emissions from solid fuel-burning appliances, he says. “Many of the chimneys destroyed or demolished may not have been fireplaces that were used regularly.”