Map of Simcoe Muskoka


Traffic-Related Air Pollution (TRAP)

Key Messages
Traffic-Related Air Pollution (TRAP)
Living Within a TRAP Exposure Area
Technical Notes

Key Messages

  • Local concentrations of traffic related air pollutants have generally decreased over the past 20 years.
  • Simcoe Muskoka residents are less likely to live in a TRAP-exposed area than Ontarians as a whole.
  • Simcoe and Muskoka residents spend an average 23-30 minutes commuting, similar to the provincial average.

Traffic-Related Air Pollution (TRAP)

  • The average annual concentrations of nitrogen oxides (NOx, NO and NO2) decreased at the Barrie monitoring station from 2003 to 2021.
  • The concentration of fine particulate matter (PM2.5) has remained constant over the previous 19 years.


Decreases in air pollutant concentrations can be attributed to reductions in emissions from both vehicles and industrial sources. Despite improvements in overall air quality, those who spend large amounts of time on or near major roads and highways, including commuters, remain at risk of high exposure to TRAP.

Living Within a TRAP-Exposed Area

  • Living within 100 m of a major road or within 500 m of a highway is considered to be within the TRAP exposure area and is associated with the onset and worsening of asthma in children as well as other adverse health outcomes.
  • In Simcoe Muskoka in 2011, less than one-in-five (17.6%) residents lived in a TRAP-exposed area
  • This is lower than the one-quarter (27.8 %) of the overall Ontario population that lived inside TRAP-exposed areas.


Children, seniors, and people with pre-existing health conditions are more vulnerable to the adverse health effects related to TRAP exposure. Many institutions that serve these vulnerable populations, like elementary schools and long-term care homes for seniors, are located with-in a TRAP-exposed area.

TRAP Exposure and Commuting

  • The average time spent commuting to or from work in 2016 was 29.5 minutes in Simcoe County and 23.1 minutes in the District of Muskoka.
  • This is similar to the average for all of Ontario of 28.8 minutes.
  • Simcoe and Muskoka both residents tend to spend slightly less time (14.4 minutes in Simcoe County and 12.7 minutes in District of Muskoka) commuting via active transport than the provincial average (15.7 minutes).
  • Simcoe County residents spend slightly more time commuting via car, truck or van, or via public transit than the provincial average, while District of Muskoka residents spend less time. Commute times are especially longer among residents of South Simcoe.


Technical Notes

Traffic-related air pollution (TRAP) is measured by nitrogen oxides (NOx) overall, and nitric oxide (NO) and nitrogen dioxide (NO2) in particular, and by fine particulate matter (PM2.5).

The air monitoring station in Dorset (Muskoka) does not monitor nitrogen oxides (NOx). The Barrie station is used to report on changes in TRAP.

Persons who commute on or near major roads and highways, whether in their own vehicle, via public transit, or through active transport, are exposed to higher concentrations of TRAP. In-vehicle concentrations of major air pollutants including PM2.5 and NO2 are similar to on-road concentrations, both of which are considerably higher than concentrations measured at air monitoring stations removed from high traffic areas. Active transport, via walking or cycling, along major routes also leads to higher exposure to TRAP, exacerbated by exercised-induced increased respiration.

Further Reading

For more information on traffic-related air pollution, see:

Page last modified February 8,2023