> Air Quality - Yonge North Subway Extension | Metrolinx Engage

Warning message

Submissions are closed.

Air Quality - Yonge North Subway Extension

← Return to Environmental Project Report Overview

Key Findings

  • Existing air quality in the Study Area is typical of urban areas in southern Ontario, with background benzene, benzo(a)pyrene, fine dust particles, and nitrogen dioxide air concentrations that are attributed to a variety of sources including industry and transportation.
  • Without mitigation, project construction activities have the potential to temporarily increase levels of air quality contaminants near the construction sites. Mitigation measures such as watering, engine anti-idling policies, stockpile covering, and others are anticipated to reduce or eliminate these potential impacts.
  • The Project is expected to improve air quality in the study area due to the reduction of ground traffic.
  • Greenhouse gas emissions are anticipated to decrease as commuters are expected to shift from the use of personal vehicles to the new subway extension, a public transit line powered by Ontario’s energy grid which has one of the lowest carbon intensities in the world.

construction dust monitor

Figure 1: Example construction dust monitor in a fenced enclosure (left side of photo)

Potential Effects & Mitigation Measures

Potential Effects:

Construction Phase

  • The Project may temporarily increase levels of air quality contaminants near construction sites for the duration of construction. Potential air quality effects would be mainly due to construction vehicle emissions, earthworks, material handling and transfer, and construction activities.

Operational Phase

  • The Project is expected to improve air quality in the study area due to the reduction of ground traffic.
  • Greenhouse gas emissions are anticipated to decrease as commuters are expected to shift from the use of personal vehicles to the new subway extension.

watering truck

Figure 2: Example watering truck used for dust suppression

Mitigation Measures:

Construction Phase

  • An air quality management plan will be developed in advance of construction.
  • A complaint response protocol will be developed as part of the construction air quality management plan to assist in timely resolution of complaints.
  • Frequent watering of construction zones to decrease dust generation.
  • Covering stockpiles of loose materials to prevent dust releases.
  • Following anti-idling procedures and controlling the amount of simultaneously operating equipment on-site.
  • Limiting simultaneous operation of construction fleet equipment where feasible.
  • Using construction equipment with lower emissions where feasible.
  • Continuous real-time monitoring of dust and other air quality parameters at construction sites to support effective deployment of mitigation measures.

Operations Phase

  • As the air quality in the Study Area is anticipated to improve, no mitigation measures are required. Some localized activities, such as future maintenance activities in the tunnel or at the train storage facility, may potentially require the development and implementation of Air Quality Management Plans to address potential short term localized air quality impacts.

← Return to Environmental Project Report Overview

Submissions are closed.