Remember the last time there was a smog advisory in the Ottawa Valley?

You'd have to go back to 2014. There were none last year and none so far this year.

Things weren't so nice about a decade ago, before Ontario closed all of its coal-fired power generation plants (the last, in Thunder Bay, closed in 2014).

In 2005 there were 25 smog advisory days in the Ottawa area and 53 across Ontario. By 2009 there were just four smog advisories in the valley. And by 2013, there was only one such advisory.

"This is a huge achievement. It's a good news story for the environment," said Paul Parker, a faculty of environment professor at the University of Waterloo, on CBC Radio's Ottawa Morning on Monday.

"On our poor days, half of the pollution comes in from the U.S., and then we were adding on top of it. So what we've done is we've dramatically reduced what we added on top of it, and so that keeps us below the worst thresholds."

Vehicles and small engines for lawn mowers, leaf blowers and the like contribute most to what remaining pollution exists in our region, along with pollution from the United States.

Parker says a focus on switching gas-powered small engines to electric ones would be a good next step for the province to reduce pollution even further.