Item - 2015.EY8.71

At the request of the Etobicoke York Community Council (EYCC) and Toronto City Council, Toronto Public Health (TPH), with the assistance of Public Health Ontario, undertook an air quality assessment study in the vicinity of ML Ready Mix, located at 29 Judson Street, in the City of Toronto. The objective of the study was to assess air quality in the vicinity of the facility and determine impacts, if any, from its operation.

Ml Ready Mix is a concrete batching facility located in the south-west end of Toronto. The concrete batching operation consists of mixing of raw materials such as cement, sand and gravel that are stored on site and delivery of the concrete product to construction sites. The community concerns that have been raised about the facility mainly pertain to dust and potential air quality impacts. Particulate matter was identified as the primary pollutant of concern related to the batching operations.

The air quality assessment study consisted of air quality monitoring, meteorological data collection, and qualitative observation near ML Ready Mix. Air quality monitoring was conducted for PM2.5 and PM10, both considered to be good indicators of emissions from such operations. PM2.5 is a term to describe air particles that are 2.5 millionths of a meter in diameter or smaller. Likewise PM10 describes air particles that are 10 millionths of a meter in diameter or smaller. Air particles of this size are a concern because they can reach deep into the lungs and are associated with adverse health outcomes.

Collected data was combined with site-specific meteorological information such as wind direction, wind speed, temperature and relative humidity. Furthermore, during the monitoring period detailed notes were made by Toronto Public Health staff about conditions and activities that could have resulted in particulate matter emissions that in turn could have contributed to localized air quality impacts. Amongst others, those include visible dust events, vehicular traffic and rail traffic.

For analysis, the results of the air quality monitoring were compared to the general background levels of particulate matter in Toronto, the concentration of PM2.5 at the Ministry of the Environment and Climate Change (MOECC) Kipling monitoring station (considered to be representative of the ML site) and the applicable health-based guidelines. The guidelines chosen for comparison were considered to be appropriate for the monitoring duration and to be protective of sensitive receptors, such as children and the elderly.

All air quality monitoring results were below health-based guidelines for both PM2.5 and PM10. The monitoring results were also consistent with the air quality measurements taken at the MOECC Kipling research station. The average 24 hour PM2.5 concentration near ML Ready Mix was slightly above the MOECC annual mean for Toronto, however, care should be taken when comparing the average 24 hour PM2.5 concentrations near ML Ready Mix to the MOECC annual mean as the monitoring near the facility was only conducted over a fairly short time period. As there were several limitations associated with the study design, the study could not determine the actual contribution of the facility to the monitored concentrations.

In general, the air quality in the vicinity of ML Ready Mix is similar to that in other parts of the City and it appears to meet the relevant health-based guidelines. As the air quality in the vicinity of ML Ready Mix is acceptable and not appreciably different from other parts of Toronto, no further air quality testing is needed.