The CN Milton Logistics Hub, a nearly finished $250-million project on about 400 acres of CN-owned land, highlights the challenge of balancing economic growth, public health and environmental protection.
The hub will move shipping containers between trains and trucks to improve efficiency. It also supports the growing demand for lower-emission transportation in Ontario, Canada and across North America since moving freight by rail instead of trucks can cut greenhouse gas emissions by up to 75 per cent, according to the Association of American Railways. Even small shifts from trucking to rail can help the environment.
For years, residents, community organizations and local governments have worked to keep concerns about air quality and health impacts in the public eye. Their efforts have increased scrutiny of the project and ensured that environmental considerations remain part of the conversation. But uncertainty can also fuel fear, particularly when discussions focus on possible risks without clear local evidence about what those risks may be.
Because of its size and impact, the project has received a lot of attention. A Community Consultation Committee, required by the Impact Assessment Agency of Canada has helped guide discussion. As a long-time member, I see the committee not only as a place to share information but also as a place that allows people to have respectful and meaningful conversations. Meetings and site visits show that even difficult topics can be discussed in a thoughtful way.
For many residents, the concerns are very personal. In Milton, truck traffic and major roads are part of daily life, so air quality is already a concern. People living near or downwind of the hub are especially worried. As an older adult, I see air quality as closely linked to health and quality of life.
The project has also gone through years of legal challenges. In 2024, a court found problems with how human health impacts were considered and sent the decision back for review. Later that year, the Federal Court of Appeal reversed this decision and allowed the project to move ahead. In 2025, the Supreme Court of Canada declined to hear another appeal, effectively ending the legal process.
I care deeply about the air we breathe. Living downwind from the hub increases my awareness of how pollution may affect long-term health. Milton already has diesel-related emissions, which makes careful monitoring even more important.
Research shows that lifestyle and environmental factors can influence brain health. Social engagement and physical activity are consistently associated with better cognitive outcomes and lower dementia risk. Environmental exposures have also attracted increasing attention. The 2024 Lancet Commission identified air pollution as a potentially modifiable dementia risk factor; observational studies link long-term exposure to PM2.5 with higher dementia risk, while greener environments are associated with lower risk.
However, these findings are based largely on observational data and remain vulnerable to residual confounding and bias. Because environmental exposures cannot usually be evaluated through randomized controlled trials, the evidence is inherently less certain than that supporting many clinical interventions. Nonetheless, given the population-wide impact of these exposures, proponents argue that urban planning, transportation and environmental policies should be considered part of dementia prevention.
Now that the legal process is over, the focus has shifted. The question is no longer whether the hub will be built, but how its effects will be measured and managed. This is a chance to move from uncertainty to evidence-based decisions.
It is important to recognize that Milton already has significant transportation activity, including Highway 401, one of the busiest truck routes in North America. Rail lines and logistics operations are also growing. The CN Hub will add to this environment, not create a new one. This makes careful monitoring essential.
Current systems provide some information but do not show the full picture. Expanding monitoring with both fixed stations and mobile units would allow for continuous tracking and focused checks when needed.
Monitoring should reflect where people actually live and travel. This includes major roads, industrial areas, near the hub and residential neighbourhoods. A rural or background site should also be included for comparison.
The types of pollutants measured should match current science. Important ones include fine particles, nitrogen oxides, ozone, ultrafine particles and black carbon. These help show the real impact of emissions.
To better understand health effects, air quality data should be linked to health data where possible. Tracking conditions like asthma or chronic lung disease can show whether changes in air quality affect people’s health. This helps move from general concern to clear evidence.
Clear and open monitoring can also build trust. When people have access to reliable and transparent information, they are better able to understand risks and focus on solutions rather than uncertainty.
The recently announced Health Canada Transportation Hub Neighbourhood Air Quality Study offers an opportunity to better understand the effects of the CN Milton Logistics Hub. By comparing air quality before and after operations begin, the study will provide evidence to support health risk assessments, planning decisions and strategies to reduce transportation-related air pollution. Results are expected in 2028.
However, a study with a defined timeline cannot address every long-term question. Building on this work, the Ministry of Environment, Conservation and Parks should expand its air-quality monitoring network in Milton with permanent stations in residential neighbourhoods, near major transportation corridors and in communities downwind of the hub, supported by mobile monitoring where needed. Together, these measures would provide a more complete picture of local air quality, help distinguish pollution sources and support transparent, evidence-based decisions that protect public health.
The CN Milton Logistics Hub highlights the challenge of balancing economic growth, public health and environmental protection. As the project moves into operation, robust air-quality monitoring offers an opportunity to rethink the conversation. The hub’s most important legacy may be whether Milton can show that rigorous science and public engagement can help communities find common ground on complex issues.
