An air quality advisory and restrictions on open burning that were in effect for the Cowichan Valley for just 24 hours has been lifted.
The Ministry of Environment and the Island Health Authority issued the advisory and related burning restrictions on Dec. 14 due to high concentrations of fine particulates in the atmosphere that were expected to persist until the current wintry weather conditions change.
But the air quality has improved since then, leading to the lifting of the advisory and related burning restrictions.
The Cowichan Valley is widely known as having higher levels of particulate matter in its air than most other areas of the province, but strategies by local governments recently to deal with the issue seem to be paying off, despite the recent air quality advisory.
Earle Plain, an air-quality meteorologist with the Ministry of Environment, said weather appears to be the major culprit in the advisory.
He said the cold weather that has blanketed the Valley during the last two weeks has left cold, dense air stagnated in place that had inhibited air movement and causing the build up of particulate matter in the atmosphere.
“It’s an effect that is being seen in the province’s valleys, like the Cowichan Valley, during this cold spell, and a number of valleys in the province’s Interior had also received air-quality advisories,” Plain said.
Overall, however, Plain said it appears there have been some “positive trends” in local air quality recently, and while the Valley’s air quality typically exceeded provincial averages, it has been in compliance for the last three years.
“That’s good news, but we really need 10 years of record keeping to be definitive on trends, and our records for the Valley only go back to 2010,” he said.
“But if the data is confirmed and air quality is actually improving in the Valley, it’s likely attributable to changes in public behaviour and the amount of information on the issue that has gotten out there.”
The Cowichan Valley Regional District released an extensive air-shed protection strategy last year, noting that hospital admissions for children with respiratory diseases were on average 70 per cent higher in the Valley than the rest of B.C. between 1998 and 2012.
The report also found asthma rates were 14 per cent higher and chronic respiratory illness in people over 45 was 50 per cent higher in the Valley.
The geography of the Valley, ringed by mountains, means bad air is often held at ground level at certain times of the year, the report stated.