What a difference a day makes.

Air quality greatly improved on Vancouver Island overnight, with most major areas dropping to a "low" health risk after being rated dangerously high just a day earlier.

According to B.C.'s Air Quality Health Index, Victoria was listed with a rating of 2 Thursday morning, meaning health risks associated with fine particulates in the air was considered to be low.

In the morning, the AQHI rated the West Shore's air quality at a 3, while up-island, Duncan, Nanaimo and the Comox Valley also had a rating of 2.

Those ratings rose slight in the afternoon, with Victoria and the West Shore hitting a "moderate" health risk of 5 and 4, respectively.

Just a day before, all of the major cities on Vancouver Island carried "very high" ratings of over 10 after winds pushed wildfire smoke from B.C.'s Interior to the coast.

The result was hazy skies on much of the island, with many residents complaining that the smoke was irritating their eyes and lungs.

Before the smoke cleared out overnight, many municipalities reported heavier concentrations of the haze late Wednesday.

The smoke was so bad, Saanich Fire had to send out a news release reminding residents that no wildfires or interface fires were burning in the area.

Environment Canada still has special air quality statements in effect for all of Vancouver Island except the North Island, but they've been updated to reflect the improvement in air quality.

"The winds shifted to a westerly direction overnight resulting in an onshore flow of fresh Pacific air along the coast," the agency said Thursday. "It will take a little longer for the Pacific air to reach inland communities of the South Coast but improvement is still expected."

Air quality ratings in the interior, including Kamloops, Whistler, and the Okanagan continued to be higher than 10 on Thursday.

B.C. has declared a state of emergency due to the 563 wildfires burning around the province, which have scorched a total area of more than 6,000 square kilometres. 

How are air quality ratings calculated? Environment Canada meteorologist Ben Weinstein explains: