VANCOUVER • Smoke from California and Oregon wildfires has cloaked Canada's third-largest city of Vancouver - known for its majestic mountain views and fresh ocean breezes - in the dirtiest air in the world this past week.
Days have been spent smarting under a thick haze that has irritated eyes and throats, and sent asthmatics gasping for breath. It has also complicated Covid-19 testing.
On Friday, despite expected smoke-clearing rainstorms, the city - 1,300km north of the biggest California fires - topped, for the second time in the week, the World Air Quality Index for worst air, after briefly ceding first place to Portland in fire-stricken Oregon in the United States.
"I'm out of breath all the time, my chest feels like it's exploding, I feel like I'm going to suffocate," said University of British Columbia doctoral student Fatima Jaffer.
"I'm afraid of the long-term damage this smoke might do to my lungs and my asthma."
The authorities for the metropolitan region of 2.5 million residents have issued daily air quality warnings since Sept 8, with things so bad that Vancouver opened five filtered "clean air shelters".
It is equivalent to smoking eight cigarettes a day, researchers noted. Officials urged people to close windows and avoid strenuous exercise or outdoor activities - especially those with respiratory illness.
Ms Jaffer, 58, said her worsening asthma added to a sense of panic and dread, as she had just recovered from Covid-19, which robbed her of her sense of smell.
Now, she worries the smog could increase her odds of reinfection or cause new health complications.
"I'd just gotten to the place of getting over the fear of Covid-19 and felt like I could breathe again," she said, "and now I literally can't."
It has been an "entire horrible week for air quality", said Mr Armel Castellan, a federal warning preparedness meteorologist.
"The fine particulate has brought our Air Quality Health Index up off the charts. "There's no doubt this is very massive and very concerning."
The same people are at most risk of smoke inhalation and the coronavirus, according to provincial health officer Bonnie Henry.
The past month has seen British Columbia's active Covid-19 cases surge 130 per cent, hitting highs more than double those at the pandemic's April peak.
"For many of us, there's confusion about what symptoms are caused by smoky skies, and what symptoms are caused by Covid-19," Dr Henry told a news conference, "particularly for people who have underlying lung disease, asthma, heart disease and diabetes."
Another vulnerable group are the more than 2,000 homeless people, many of whom have chronic illness, a recent survey found.
"If you're outside and homeless, and surrounded by this smoke and the pandemic, you can't get away from any of these things," said Mr Jeremy Hunka of the Union Gospel Mission. "It's hitting a group of people that generally have been just left far more vulnerable."
For North Vancouver professional dog-walker Barry Appal, 64, he and his wife, who is 10 years his senior, have had to wear masks outdoors and avoid usual strenuous trails. "After a half-hour you could feel it in your lungs and get a headache," he said. "We're active and healthy, but with Covid-19 around, picking up any respiratory thing could become a bigger problem than normal."
Mr Appal is most worried for his 30-something nephew who suffers from cystic fibrosis, saying: "He's very susceptible to anything to do with his lungs.
"He's already freaked out about Covid - that could wipe him right out at the drop of a hat."
Mr Castellan, the meteorologist, said conditions should improve this week thanks to brewing Pacific storms clearing the air.
But with the "fingerprints of climate change" clearly visible in the year-after-year worsening wildfire seasons, he warned that "we're not done with this yet".