Where have smog days gone? Hamilton hasn't had one since 2013

Despite days of sweltering heat in the past week, the city has yet to record a single smog day for 2015. And to find the last smog advisory, you'll need to turn back the clock to 2013, leaving a city long known for its industrial "smell" breathing easy.

"Usually it's the triple h's: the heat, the humidity, and the haze. And wow, we haven't seen them," said Dave Phillips, climatologist at Environment Canada.

It's not all big dramatic actions. We just have to keep plugging away at it and nipping away at it and we'll get where we'll need to be.- Denis Corr, Clean Air Hamilton

He said while the temperature was above 30 degrees for most of the week, the humidex didn't climb above 40. It's that combination that leads to the last of 'the triple h's" — haze — which is usually a telltale sign of smog.

"Usually you get that milky white sky," Phillips said. "We didn't see it. The humidity wasn't quite as high."

45 smog days in 2005, zero in 2015

Hamilton has had its share of smog. There were 18 smog days in 2012, 31 in 2007, and 45 in 2005.

There were no smog advisories last year and just two in 2013. Phillips said the reasons for disappearance of smog days is multifaceted: the air index system has recently changed, summers have been cooler, and pollution that contributes to smog has been reduced.

Dennis Corr, chair of Clean Air Hamilton said that long-time residents will have noticed the change in Hamilton's air the most. He said people today are breathing air that is 90 per cent cleaner than it was in the 1970s.

"Really it's been two per cent a year here, three per cent there. It's a combination of a lot of different actions," Corr said.

"So there's actually a lesson there in the climate change issue as well, that it's not all big dramatic actions. We just have to keep plugging away at it and nipping away at it and we'll get where we'll need to be… All these things add up."

In June 2015, Environment Canada and the Ontario Ministry of the Environment and Climate Change (MOE) switched over from the Air Quality Index (AQI) to the Air Quality Health Index (AQHI).

Corr said it calculates the air quality in a slightly different manner, looking at direct health impacts, and provides the index on a scale of 1 to 10, rather than 1 to 100.

Carcinogens still in Hamilton's air

Phillips said comparing AQHI against historical AQI is "apples to oranges" and that the AGHI is "starting afresh" and should be compared with future years. Meanwhile Corr said the two scales are "fairly equivalent" and more importantly for this year, he doubts any of the days so far would have triggered a smog advisory on the old AQI, compared to the new AQHI.

It leaves cooler summers and cleaner air as the only possible outcomes how Hamilton has escaped smog for nearly two years.

Corr said Hamilton is a city to be envied for how it monitors air quality. The ministry has three monitoring stations (the Mountain, downtown and west end) and the industrial sector of the city is watched by the Hamilton Air Monitor Network (HAMN). Add in two moveable air quality monitors from the city's public health department, and one monitor in a special outfitted van from Clean Air Hamilton, and Corr said you have a level of detail no other city has, which is mapped live and updated hourly.

Most markers in air quality are down, although there are still high levels of benzo[a]pyrene and benzene — both of which can cause leukemia and other cancers. They are present in levels higher than the MOE's incoming air quality standards, and aren't going away for a while. Ozone levels are variable and may be increasingly slightly.

And despite the improvements, air quality remains a significant health issue. The latest numbers, from 2011, show that in Hamilton each year, air pollution contributes to about 186 premature deaths, 395 respiratory hospital admissions and 322 cardiovascular hospital admissions.

Corr also warns about working out when there are increased amounts of pollution in the air.

"If you're jogging, your respiratory rate goes up so your dose of air pollutants can be as much as seven or eight times higher," Corr said.

Even worse, is heading out onto the highway.

"The worst case is to be on a 400 series highway. That's like two or three times worse then anywhere in Hamilton," Corr said. "We recommend that you put your ventilation system on your car on re-circulate before you go on the highway."