Vancouverites beat the July heat at Stanley Park's Second Beach. (CBC)

High temperatures scorching B.C. reached 40 C in some areas of Vancouver Island on Tuesday, and the mercury is expected to be in the low to mid-30s elsewhere in the south of the province for most of the week.

Usually balmy Port Alberni, about 90 kilometres west of Nanaimo, reached 40 C Tuesday, and the temperature is forecast to hit 40 C on Wednesday.

The high in Port Alberni eclipsed even the frequent provincial hotspot of Osoyoos, in the Southern Interior, which hit 37 C on Tuesday.

'Honestly, it's like almost unbearable.'—Regan Lindors, Sproat Lake Marine Patrol

When it gets hot in Port Alberni, many residents head for Sproat Lake, about 10 kilometres west of town.

"I think that a lot of people will probably be off work and be coming out here because it's like unbearable in town. It's awful. The public beaches are pretty packed," according to Regan Lindors of the Sproat Lake Marine Patrol.

Even with her cool job, Lindors admitted the heat is getting to her.

"Honestly, it's like almost unbearable," she said. "If you're just sitting in your boat, and you're not really moving or you're sitting on the beach, you're just dripping sweat. It's so hot."

Air pollution also worsening

The extreme conditions are also raising concerns about air pollution and sun exposure in the Lower Mainland.

BC Place sits under smoggy skies during Vancouver's July hot spell. (CBC)

Air quality in Metro Vancouver and the Fraser Valley Regional District is forecast to continue to deteriorate due to high smog levels, according to an advisory issued by Environment Canada and the B.C. Environment Ministry.

The advisory also cautions that the worsening conditions are expected to persist Wednesday and perhaps later in the week.

Most of Metro Vancouver and the central Fraser Valley registered six out of 10 on an air quality health index scale posted by the Environment Ministry shows.

Environment Canada's UV Index, indicating the amount of ambient ultraviolet light, is at Level 8, which calls for extra precautions when outdoors, as unprotected skin will be damaged and could burn quickly.

People are advised to avoid the sun between 11 a.m. and 4 p.m., and take full precautions: Seek shade, cover up, and wear a hat, sunglasses and sunscreen.

Retailers report hot sales of fans and air conditioners in the Lower Mainland and Vancouver Island.