An air quality advisory issued on Friday by the Ministry of Environment and Climate Change and in partnership with Island Health has now been lifted in the Duncan area.
As a precaution, open burning restrictions will remain in effect until Monday. Any open burning will require a permit or approval from the Ministry of Environment, and may not take place in the Cowichan Valley within a 15 kilometre radius from Duncan City Hall.
The current weather pattern is the result of a strong ridge of high pressure sitting over the south coast.
Meteorologists say the ridge can trap emissions due to stagnant air and can cause high concentrations of fine particulate matter, resulting in the prior advisory for Duncan and Courtenay being issued earlier this week.
Levels on Friday around 8 a.m. found fine particulate concentrations averaged 31 micrograms per cubic metre. The provincial air quality objective is 25 micrograms per cubic metres.
Officials say conditions have greatly improved, but air movement is still low.
“Its definitely something that is driven by meteorology and by emissions,” said Earle Plain, an Air Quality Meteorologist for the Ministry of Environment and Climate Change. “Cowichan is a valley, it’s bounded by all sides by topographical features, like mountains. What that does is it also creates a situation where you can end up with stagnant air just because things are not open to the ocean and move as freely.”
Exposure was a concern for infants, the elderly and people who have diabetes, lung or heart disease. People with chronic underlying medical conditions were also advised to avoid strenuous exercise until the statement was lifted.
Officials say residents can reduce emissions by avoiding the use of wood stoves and fireplaces unless necessary, burn well-cured dry wood and ensure an adequate supply of combustion air, avoid backyard burning and reducing the use and idling of vehicles.