The orange haze shrouding Nelson and light ash falling are the a result of a large fire burning south of Christina Lake near Orient, Wash.
Fire information officer Fanny Bernard confirmed no fires of note are burning in the immediate area.
According to the BC Wildfire Service website, four remote fires are being left to burn east of Kootenay Lake in the Purcell Mountains totalling more than 400 hectares, the largest of which is the 201-hectare Redding Creek fire.
Southeast Fire Centre fire weather behaviour specialist Ron Lakeman said rain is forecast this weekend with a potential for five to 10 mm of showers.
He said the weather will begin to transition Friday and temperatures are expected to be cooler through the weekend.
According to the BC Air Quality website the air quality in Castlegar is currently rated as a moderate health risk, which is expected to drop to a low health risk tomorrow.
A moderate health risk rating means there is no need to modify outdoor activities unless you experience symptoms such as coughing and throat irritation.
The Ministry of Environment considers people with heart or breathing problems as at risk and you should consider reducing or rescheduling strenuous activities outdoors if you experience symptoms when the air quality is moderate.
A campfire ban remains in place throughout the Southeast Fire Centre.