Smog is a word that comes from putting together smoke and fog.

And in Toronto, smog was the sickly brown haze that came from the U.S. industrial heartland to the south and parked itself over the city in July of 1988.

"The air is thick and heavy with tons and tons of toxic chemicals," said CBC reporter Brenda Craig on what was apparently the second day of heavy smog.

'Very unusual'

Lou Shenfeld of Environment Ontario said the city might experience another day with a smog reading of 90. A normal day at the time had a reading of 10 to 20. (Newshour/CBC Archives)

The previous day, the air quality index in the Greater Toronto Area had read between 84 and 90, when the usual number was 10 to 20.

"It was very unusual to get up as high as an air quality index of 90," said Lou Shenfeld of Environment Ontario. "But we may get there again today, because there's very little change in the weather."

The air quality index, a measurement of harmful particles in the air, had been adopted by the province earlier that year. A number under 32 was considered "acceptable," according to the Globe and Mail.

The culprit was a heat wave that had migrated north from Ohio and surrounding states, where "giant smokestacks" from steel mills and coal-fired power plants generated the pollution.

"The smog is loaded with sulfates and nitrogens," added Craig, as the camera showed multiple aerial shots of the smog.

From Ohio to Ontario

Jim Bradley, Ontario's Minister of the Environment, said the province had asked the U.S. state of Ohio to reduce its emissions by 60 per cent. (Newshour/CBC Archives)

Ontario had tried, mostly in vain, to prevail on the states where the dirty air originated.

"We've pressed the state of Ohio and other states to cut back on their emissions," said Environment Minister Jim Bradley. "If they would do that ... we wouldn't be facing this problem today."

But that didn't mean Ontario was off the hook.

The province's own coal-fired generators and automobile exhaust exacerbated the smog.

"I am, and the rest of the people in the province are contributing to the problem," said Bradley. "We can all cut back a bit, and it may make the difference between somebody being admitted to a hospital for a respiratory problem, or not."

As for what it would take to get rid of the smog, Craig said rain was in the forecast.

"That will wash the pollution out of our air and into our lakes, our rivers and our forests," she explained. "In other words, the big smog will become a big acid rain."

Smog is not the problem it once was in Toronto. According to the provincial government website airqualityontario.ca, annual smog advisory days peaked at 53 in 2005 but were down to zero in 2014.