Air quality


Energy, air quality and climate change

What’s the link?

In most Ontario homes, we use natural gas to heat our rooms and our water.
Over 25% of Ontario’s electricity is generated using natural gas and coal.

Burning these fossil fuels creates air pollution, smog and greenhouse gas emissions, and those emissions cause climate change.

Environmental issues are at the top of Canadians ‘most important list’. Among environmental concerns, Canadians have identified climate change as one of the most urgent. We’re not alone. Climate change is considered by many scientists to be the most serious threat facing the planet today.

What can you do?

You can make a difference through energy conservation. When we use less water, fuel and energy, we cause fewer greenhouse gas emissions and help to prevent climate change.

Find ways to save money, save energy and prevent climate change.

What are greenhouse gases?

Greenhouse gases (GHGs) are gases in the atmosphere that trap energy from the sun. Naturally occurring GHGs include water vapour, ozone, carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O). Without them, the Earth’s average temperature would be about 33°C lower than it is, making the climate too cold to support life (Schneider, 1989). While these naturally occurring gases are what make life possible, a serious concern today is the enhanced effect on the climate system of increased levels of some of these gases in the atmosphere, due mainly to human activities

source: Environment Canada

Air Quality Monitoring

The Ministry of the Environment (MOE) and the City of Guelph, recommissioned the Air Quality Monitoring Station in May 2001.  The Monitoring Station, located in Exhibition Park (behind the arena), measures and records air quality levels on a daily basis. These measurements are used to declare SMOG warnings, advising residents of unhealthy air quality conditions.

Among other air pollutants, the monitoring station measures concentrations of ground level ozone. Exposure to ground level ozone can cause coughing, headaches, nausea, and irritation of mucous membranes, and may also cause premature aging of the lungs. Those at particular risk include young children, the elderly, asthmatics, and anyone with existing respiratory or coronary conditions.

Under Ontario’s ambient air quality criterion for ozone, air quality is considered unhealthy when concentrations of ozone exceed 80 parts per billion, averaged over one hour. Although much of the region’s smog is blown in from sources in the U.S. midwest, local sources also contribute to the problem. In southwestern Ontario, ozone levels are generally highest from 2 in the afternoon to 8 at night, and lowest in the morning.

View today’s Air Quality Index

Clearing the air on car idling

City of Guelph Idling By-law

Idling By-law

Please respect the rules around unnecessary idling in our community. Idling gets you nowhere and is bad for your health and your pocket book. Did you know that on average, Canadians create approximately 1.6 million tonnes of greenhouse gases each day by idling unnecessarily. That’s enough to take your breathe away!

Unnecessary vehicle idling is a problem. But you can be a part of the solution – all it takes is the turn of a key.

How can we help you?
Report an idling vehicle

Idling gets you nowhere

Reduce “warm-up” idling to 30 seconds.

  • Turn your engine off if parked for more than 10 seconds. A vehicle left idling for more then 10 seconds uses more gas then it would take to shut off and restart the engine.
  • Avoid using a remote car starter.
  • Try an emission-free form of transportation – such as walking or cycling. Carpooling or public transit will also help reduce emissions.

Quick facts about idling

On average, motorists idle their vehicle for five to 10 minutes every day. According to Natural Resources Canada, if every driver in Canada avoided idling for five minutes a day, we would prevent 1.6 million tonnes of carbon dioxide (the principle greenhouse gas) from entering the atmosphere.

  • Canadians waste about $100 in fuel, each year, due to idling.
  • Engine exhaust contains more than 40 hazardous air pollutants.
  • Health Canada estimates that 5,000 Canadians die prematurely each year because of air pollution.

Facts and Fiction

Fiction: Idling helps to warm up your engine before driving.

Fact: Driving your car is the best way to warm it up. Most modern cars need no more than 30 seconds of idling to warm up. Even in Winter, unless your windshield is covered in ice, you don’t need to warm up your car for more than 30 seconds.

Fiction: Idling is good for my engine, it keeps it tuned up nicely.

Fact: Idling can actually cause unnecessary wear and tear on your engine and its components such as the spark plugs and the exhaust system.

Fiction: Turning off and restarting my engine is bad for the battery and the starter motor.

Fact: Actually, re-starting your engine has very little impact on engine components such as the battery or the starter motor. If you are stopped for more than 10 seconds, unless in traffic, you should turn your engine off.

Smog Day Response

What is Smog and where does it come from?

Smog in Ontario is usually the result of the migration of pollutants from the United States combining with unfavourable weather patterns. There are, however, local sources of pollution that can contribute to the severity of smog events. Ontarians can take personal actions – such as driving better-tuned cars or driving less, car-pooling, avoiding the use of gas-powered lawn mowers, or lowering the use of air conditioning during the summertime – to lessen the impact of smog. All of these “spare the air” actions will help, especially for vulnerable persons who suffer from breathing difficulties or other health concerns.

Ground-level ozone and fine particulate matter are key components of smog. Ground-level ozone is formed when nitrogen oxides and volatile organic compounds react in the presence of sunlight. Ground-level ozone is different from the ozone layer high above the earth that protects us from the sun’s harmful UV rays. Fine particulate matter is also formed from chemical reactions in the atmosphere as well as through direct emissions. The formation and transport of both ozone and fine particulate matter is strongly dependent on meteorological conditions.

In Ontario, elevated concentrations of ozone are generally observed on hot, sunny days from May to September, between noon and early evening. On such days, fine particulate matter levels are often elevated but unlike ozone they can remain high throughout the day and night. Elevated levels of fine particulate matter can occur throughout the entire year, especially during stagnation periods when meteorological conditions are not conducive for the dispersion of pollutants.

Source: Ministry of the Environment (

Tips to help you breath easier on Smog Days

  • Delay outdoor activities on smog days, as smog may cause breathing difficulties and eye, nose and throat irritations
  • Avoid using gas-powered equipment until the smog advisory has passed
  • Postpone mowing to another day in summer
  • Enjoy light meals that require little or no cooking
  • Stay at work for lunch or walk to a nearby restaurant
  • Avoid the use of oil-based products such as paints, solvents, or cleaners. They contain volatile organic compounds (VOCs) that contribute to smog.
  • Postpone refuelling your vehicle to later in the day when air pollution levels are lower