You live next to a construction site. For the past few weeks, you’ve noticed a thin layer of gray dust on your furniture, even when the windows are closed. Your children are coughing more often. You’re wondering if it’s just your imagination, or if this dust is actually affecting the air you breathe at home.
You’re right to be concerned. Air quality in Montreal isn’t as good as you might think. According to IQAir data for 2025, the average concentration of PM2.5 fine particulate matter in Montreal is 8.9 µg/m³, which is 1.8 times the level recommended by the World Health Organization. And since 1990, total particulate matter in the air has increased by 34% in Canada.
In Montreal, construction sites are everywhere. The Plateau-Mont-Royal is undergoing a transformation, Rosemont is seeing constant renovations, and Montreal North is getting a facelift. This is good for the city’s development, but it comes at a cost to air quality.
If you live in a house built before 1980—and there are many of them in Montreal—you're even more at risk. These older buildings often have ventilation systems inadequate systems that let dust in from outside and circulate it throughout the house without filtering it effectively.
Why Construction Dust Is a Real Problem in Montreal
Construction dust isn't just an eyesore. It's a documented public health problem, especially in a densely populated city like Montreal, where construction sites are often just a few meters away from homes and schools.
Montreal is a city that is constantly evolving. Aging buildings are being renovated, infrastructure is being modernized, and new buildings are springing up in developing neighborhoods. This is both normal and necessary. But every construction project generates significant amounts of dust that become airborne.
This dust doesn’t stop at the construction site’s boundaries. It travels on the wind, seeps into neighboring homes, settles on balconies, and enters through ventilation systems. In densely populated neighborhoods such as Plateau-Mont-Royal, Rosemont, and La Petite-Patrie, where buildings are right up against one another, the impact is even greater.
Data on citizen complaints filed with the City of Montreal show a steady increase in reports related to construction dust since 2020. Residents are complaining of respiratory problems, excessive dust in their homes, and impacts on their quality of life.
What makes the problem more complex in Montreal is the duration of the projects. A major renovation or new construction project can last for months, sometimes more than a year. Neighbors are exposed to dust on a continuous and prolonged basis, which increases health risks.
What Construction Dust Actually Contains
When we talk about «construction dust,» we’re not just talking about ordinary dirt. It’s a complex mixture of particles that can be truly hazardous to your health.
Construction dust contains crystalline silica, which comes from cutting and drilling concrete, brick, and stone. Silica is classified as a carcinogen by the Canadian Centre for Occupational Health and Safety (CCOHS). Repeated exposure can cause silicosis, a serious and irreversible lung disease.
There are also particles of concrete, plaster, mortar, and cement. When these materials are cut, sanded, or demolished, they release fine particles that remain suspended in the air for hours.
In buildings constructed before 1980—and there are a great many of them in Montreal—there is an additional risk: asbestos. Many building materials used before that time contained asbestos. When these buildings are renovated or demolished, asbestos fibers can be released into the air. Asbestos is a known carcinogen that causes mesothelioma and other serious diseases.
The most dangerous particles are those known as PM2.5 and PM10—particles less than 2.5 or 10 micrometers in diameter. To put that in perspective, a human hair is about 70 micrometers in diameter. These particles are so fine that they can penetrate deep into the lungs and even enter the bloodstream.
You can't see them with the naked eye. You can't smell them. But they're there, and they affect your health every time you breathe.
Why Montreal Is More Vulnerable Than Other Cities
Montreal has certain characteristics that make it particularly vulnerable to construction dust pollution.
First, it is an old city with an aging housing stock. Entire neighborhoods such as Rosemont, Villeray, and Montréal-Nord were built between the 1950s and 1970s. These buildings are reaching an age where they require major renovations, and in some cases, complete demolition and reconstruction.
Second, it’s a densely populated city. Houses and apartment buildings are close together, especially in the central districts. When there’s a construction site on a street in the Plateau, residents of 20 to 30 adjacent homes are directly affected.
Montreal’s climate also plays a role. Winter freeze-thaw cycles accelerate the deterioration of buildings and infrastructure. This creates a constant need for repairs and renovations. Cracks in concrete, damage to foundations, roofing problems—all of this leads to construction work and dust.
Urban winds exacerbate the problem. In Montreal, winds can be quite strong, especially in the fall and spring. These winds carry dust from construction sites over long distances. A construction site located just two or three blocks from your home can still affect the air quality inside your home.
The number of projects underway at the same time is staggering. At any given moment, there can be dozens of active construction sites in a single borough. The cumulative effect of all these construction sites creates a nearly constant cloud of dust in some neighborhoods.
Direct Impacts on Health and Indoor Air Quality
Construction dust doesn't stay outside. It gets into your home and directly affects your health and that of your family.
Effects on Adults, Children, and People at Risk
According to Health Canada, exposure to fine particulate matter increases the risk of respiratory problems by 20 to 30 %, even among healthy adults. This includes worsening asthma, chronic bronchitis, and more frequent respiratory infections.
For children, the risks are even higher. Children’s lungs continue to develop until adolescence. Repeated exposure to construction dust during these critical years can affect their long-term lung function. Children also breathe faster than adults, so they inhale proportionally more polluted air per kilogram of body weight.
We regularly work with families aged 35 to 55 who live near active construction sites. Many of them contact us because their children have started coughing at night, have a constantly runny nose, or are missing school more often due to respiratory problems. Parents tell us that this started when construction began in the neighborhood.
People with asthma or other pre-existing respiratory conditions are particularly vulnerable. Dust acts as an irritant that triggers asthma attacks and worsens symptoms. Older adults, whose immune systems are weaker, are also at greater risk of developing complications.
There are also effects that aren’t immediately noticeable: chronic fatigue, frequent headaches, and eye and throat irritation. These symptoms are often attributed to other causes—stress, lack of sleep, or seasonal allergies. But when you improve the air quality in your home, these symptoms often disappear.
Why Invisible Dust Is the Most Dangerous
One of the most dangerous myths about construction dust is the idea that «if I can’t see anything, everything’s fine.» It’s actually the exact opposite.
Visible dust—the kind that settles on your furniture and that you can see floating in a ray of sunlight—is generally made up of larger particles. Your body has defense mechanisms against these particles. The hairs in your nose and the mucus in your upper respiratory tract trap them before they reach your lungs.
But PM2.5 and PM10 particles are too small to be seen. They bypass your body’s natural defenses and penetrate deep into your lungs. Some can even cross the lung barrier and enter your bloodstream, potentially affecting your heart and other organs.
These fine particles remain suspended in the air for hours, sometimes even days. They circulate throughout your home. If your ventilation system doesn’t have adequate filtration, it will spread this invisible dust throughout every room.
Your heating and ventilation system can become a highway for dust. Air enters through the ducts, circulates throughout your home, and if the ducts have never been cleaned, they accumulate layers of dust that are constantly recirculated.
We regularly inspect homes where the owners tell us, «I clean all the time, but there’s always dust.» When we open the ventilation ducts, there are sometimes centimeters of dust buildup. Every time the system runs, it blows this dust into the air that the family breathes.
Common Myths About Construction Dust (and the Truth)
There are many misconceptions circulating about how to protect yourself from construction dust. Let's debunk some of the most common myths.
Myth #1: A simple mask is enough
Many people think that a standard construction mask or a surgical mask will protect them from construction dust. That's not true.
Surgical masks and ordinary cloth masks filter out less than 50 % of fine particles. They are designed to block larger droplets, not PM2.5 particles, which are the most dangerous.
For effective protection against construction dust, you need a certified N95 or R95 mask. These masks filter out at least 95 % of particles 0.3 micrometers and larger. But even with an N95 mask, it must fit snugly against your face; if air leaks in from the sides, you’re not protected.
And wearing a mask all the time in your own home isn't a viable solution. You can't live like that for months on end. The real solution is to keep dust out and purify the indoor air.
Myth #2: Dust stays outside
«The construction site is outside, not in my house, so I’m fine.» That’s what many homeowners think—until they start seeing dust build up on their furniture.
Construction dust is hard on the walls of your home. It gets in through several different routes:
- By breakdown: If you have an air exchanger or a mechanical ventilation system, it draws in air from outside. If that air contains construction dust and your system does not have HEPA filtration, that dust enters your home directly.
- Through the ducts: Visit ventilation ducts Older units may have leaks or poorly sealed joints. Dust seeps in and circulates throughout the system.
- Through windows and doors: Even when closed, older windows and doors aren't completely airtight. Air (and the dust it carries) seeps through small gaps.
- By negative pressure: When your ventilation system or range hood draws air out of the house, it creates negative pressure. Outside air (along with dust) is drawn inside through any available openings to restore the pressure balance.
We’ve worked with homeowners whose ventilation ducts had never been cleaned since the house was built 15–20 years ago. When construction began on their street, dust accumulated in the ducts, and the system distributed it throughout every room. Cleaning the ducts made a huge difference.
Myth #3: Watering the construction site solves everything
It's true that contractors are often required to spray water on dusty areas to reduce the amount of dust in the air. It's a basic control measure that helps.
But in Montreal, this method is only somewhat effective, especially during the colder months. When the temperature drops below zero, you can’t really water a construction site—the water freezes. Even during the warmer months, watering reduces dust but doesn’t eliminate it completely.
Once the watered surface dries, the dust becomes airborne again. Urban winds stir it up once more. And watering does nothing to combat the fine dust that is already suspended in the air or has already seeped into neighboring homes.
The real solution requires a combination of measures: control at the source (water spraying, dust screens, less dust-generating work methods), plus personal protection measures in homes (filtration, sealing, and cleaning of ventilation systems).
How Construction Dust Gets Into Your Home
Understanding the paths dust takes helps you better protect your home. Dust doesn't magically pass through walls—it follows specific paths.
Through ventilation and air ducts
Your ventilation system is designed to circulate air throughout your home. But if the filters aren't adequate or the ducts are dirty, the system can become a source of pollution.
Homes built before 1980 are particularly problematic. At that time, ventilation systems were much simpler—often just an exhaust fan in the bathroom and one above the stove. There was no air exchanger, no centralized filtration, no air quality control.
These old houses rely mainly on natural air infiltration to refresh the air; air enters through cracks and gaps around windows and doors. When there is a construction site nearby, the air that enters is filled with dust.
Studies show that homes in Montreal built before 1980 may have up to twice as many toxic particles in their indoor air compared to modern homes with adequate ventilation and filtration.
Even newer homes aren’t immune. If your ventilation ducts have never been cleaned, they accumulate dust, debris, and sometimes even mold. When new construction dust enters this already clogged system, the problem gets worse.
The buildup in the ducts is invisible until someone opens them up and looks inside. We’ve even found ducts so clogged that air could barely get through. The system was working twice as hard to force air through all that blockage, and every time it ran, it sent clouds of dust into the rooms.
Through doors, windows, and negative pressure
Older windows and doors are never completely airtight. Over time, weatherstripping deteriorates, frames warp slightly, and tiny gaps appear. These gaps are enough to let air and dust seep in.
Urban winds play an important role in Montreal. Winds can be quite strong, especially between buildings where they pick up speed (the Venturi effect). These winds blow dust against your house and force it through even the smallest openings.
Negative pressure is a phenomenon that many homeowners don't understand. Here's how it works: when you use your range hood, a bathroom fan, or a ventilation system, they expel air out of the house. This air must be replaced; otherwise, you would create a vacuum.
Replacement air enters through the paths of least resistance: the gaps around windows and doors, cracks in the walls, and openings around pipes and electrical wires. If the outside air is laden with construction dust, that dust enters along with it.
The difference between a condo and a single-family home is significant. In a condo, you’re often better protected because the building generally has a ventilation system Centralized with some filtration. Your walls are shared with other units, not with the outside. You have less surface area directly exposed to outdoor dust.
A single-family home has four exterior walls, a roof, and often a basement or crawl space that is in contact with the ground. All of these surfaces are potential entry points for dust. You also generally have more windows and doors. Each opening is a pathway for dust to enter.
Effective Solutions for Protecting Indoor Air Quality
Now that we understand the problem, let's talk about practical solutions. There are steps you can take right away, and others that require an investment but will protect your home in the long run.
Immediate (short-term) measures
Invest in a good HEPA air purifier
An air purifier with a HEPA (High-Efficiency Particulate Air) filter can capture 99.97% of particles 0.3 micrometers and larger. That’s exactly what you need to filter out PM2.5 fine particles.
For a typical 1,200- to 1,500-square-foot home, you’ll need one or two air purifiers, depending on the layout of the rooms. Place one in the master bedroom and one in the living room or common area where the family spends the most time.
Good residential HEPA air purifiers cost between 200 $ and 500 $. Yes, it’s an investment. But compare that to healthcare costs: a trip to the emergency room for an acute asthma attack can cost you hours of your time, plus potential medical expenses. Medications to treat chronic respiratory problems can easily cost 1,000 $ to 5,000 $ per year.
Be sure to replace the filters according to the manufacturer's recommendations, typically every 6–12 months. A clogged filter no longer filters effectively and may even become a source of pollution if it releases the particles it has trapped.
Close the windows during peak construction hours
If you know that the neighboring construction site is doing demolition or cutting concrete between 9 a.m. and 3 p.m., keep your windows closed during those hours. Open them early in the morning or in the evening, once the work is finished, to let in fresh air.
Clean regularly with a HEPA vacuum cleaner
A standard vacuum cleaner will suck up large particles but will blow fine particles back into the air through its exhaust system. A vacuum cleaner with a HEPA filter captures these particles instead of releasing them back into the air.
Vacuum frequently—two to three times a week if you live near an active construction site. Focus on areas where dust accumulates: near entrances, under windows, and in corners.
Use doormats and take off your shoes
Construction dust sticks to the soles of your shoes. Place absorbent mats at all your entrances and get into the habit of taking off your shoes when you come in. Wash these mats regularly.
Structural measures (medium- to long-term)
Immediate measures help, but for true, long-term protection, you need to address the structural causes of dust infiltration.
Have your ventilation ducts professionally cleaned
This is probably the most important step if you live near a construction site. Clean ducts ensure that your ventilation system doesn't spread accumulated dust throughout your home.
Professional duct cleaning includes:
- The Comprehensive Inspection of the camera system
- Mechanical cleaning of ducts using rotating brushes
- Powerful suction with HEPA filtration (to prevent dust from being released into the air)
- Cleaning Grates, Diffusers, and Dampers
- Inspection and Cleaning of the Main Ventilation System
For a typical Montreal home, it takes about 3–5 hours and generally costs between 400 $ and 800 $, depending on the size of the system. It’s recommended every 3–5 years under normal conditions, but if you’re near an active construction site, you may need to have it cleaned more frequently.
Have your air exchanger inspected and maintained
If you have an air exchanger (VRC or VRE), it must be cleaned and maintained regularly. The filters should be replaced every 3–6 months. The heat exchanger core should be cleaned annually.
If your air handler has standard filters, consider upgrading to MERV 13 or higher filters, which will capture significantly more fine particles.
Improve the airtightness of your building envelope
Conducting an air-tightness test (blower door test) can identify where air and dust are entering your home. A professional can then seal these leaks with caulk, expanding foam, or other sealing materials.
Common areas to be sealed include:
- Around windows and doors
- Pipe and electrical wire penetrations
- The junctions between the basement and the ground floor
- Around bathroom and kitchen vents
- Attic access hatches
A more airtight home breathes better if it has an adequate mechanical ventilation system. That’s the winning combination: preventing uncontrolled air infiltration and providing controlled ventilation with filtered air.
Recommended Professional Solution
Doing all of this on your own may seem complicated. That's where an indoor air quality professional can make a difference.
At Vortex Air, we offer a Free indoor air quality inspection. We come to your home, assess your ventilation system, check the condition of your ducts, and identify potential sources of pollution and air infiltration.
We clearly explain what we find and what needs to be done. There’s no pressure to buy services you don’t need. Just honest information so you can make the best decision for your family.
If you decide to proceed with cleaning or renovations, we use professional-grade equipment with HEPA filtration to ensure we don’t make the problem worse by stirring up dust. Our INVC-certified team (currently in the process of NADCA certification) follows industry best practices.
Have your indoor air quality checked for free by calling us at 514-214-7492 or visiting vortexair.ca. It’s a risk-free first step toward understanding your situation and protecting your family.
Standards, Regulations, and Responsibilities in Montreal
There are regulations in place to protect citizens from construction dust. Knowing your rights and the contractors' obligations can help you navigate the situation.
Role of the CNESST and the City of Montreal
The Commission on Occupational Standards, Equity, Health, and Safety (CNESST) establishes exposure limits for crystalline silica for workers. The current limit is 0.025 mg/m³ over an 8-hour workday.
Although these limits technically apply to workers on the construction site—not to nearby residents—they give an idea of how serious the problem is. If the dust is dangerous enough to require strict exposure limits for healthy adults working on the construction site, imagine the impact on children, the elderly, and people with respiratory problems who are involuntarily exposed to it.
The City of Montreal also has regulations regarding construction dust. Contractors must take reasonable measures to minimize dust dispersion, such as watering, dust screens, and less dusty work methods.
If you are affected by a nearby construction site that is not complying with these requirements, you have the right to file a complaint with the City. You can call 311 to file complaints about air quality and construction-related nuisances. The City may send inspectors and require corrective action.
What Entrepreneurs Are Legally Required to Do
Contractors have legal obligations to control dust on their job sites. This includes:
- Installing Fences and Screens around the construction site to limit the spread of dust to neighboring properties.
- Water dusty areas on a regular basis, especially before and during demolition, excavation, or cutting of materials.
- Use low-dust work methods Whenever possible, for example, use saws with built-in dust extraction to cut concrete instead of dry methods that generate a lot of dust.
- Cover dusty materials during transport and storage.
- Clean the streets where their trucks drive to prevent mud and dust from being spread throughout the neighborhood.
If a contractor fails to meet these obligations and you are directly affected, document the situation with photos and videos, note the dates and times of the incidents, and file an official report with the City.
Why Choose Vortex Air to Protect Your Indoor Air
When it comes to your family's health, you want to work with someone who takes the issue seriously and has the expertise to really make a difference.
Our humane and certified method
We’re not a big, impersonal company where you talk to a different representative every time. At Vortex Air, Mohamed and Omar, our co-owners, are personally involved in every major project. You speak directly with the people who know the work and care about the results.
Our team of more than five INVC-certified technicians follows strict industry protocols. We are currently in the process of obtaining NADCA certification, which represents international recognition of the standards we adhere to.
We use professional-grade equipment with HEPA filtration to clean your ducts. That means we don’t just move dust from one place to another—we capture it and remove it from your home. Many less reputable companies use ordinary vacuum cleaners that blow some of the dust back into the air while they work. Not us.
We protect your home while we work. We put down drop cloths, use floor protectors, and clean everything up before we leave. You’ll never even know we were there—except that your air is now much cleaner.
Social Proof and Local Trust
We have served more than 500 satisfied customers throughout Montreal, Laval, Longueuil, the North Shore, and the South Shore. Our customers come back to us year after year because they know they can trust us.
We work in all types of buildings: old houses in Rosemont, triplexes on the Plateau, modern condos on the South Shore, and single-family homes in Laval. We understand the specific challenges associated with each type of property.
Our reputation is built on honesty. We’ll never tell you that you need a deep clean if a simple maintenance cleaning is enough. We’ll never sell you additional services you don’t need. We give you the information, show you what we find, and let you decide.
We're available 7 days a week, from 7 a.m. to 9 p.m. If you have a question or concern, you can call us at 514-214-7492 (available 24/7) and speak with someone who can really help you.
Talk to a local expert today to discuss your specific situation. We’ll give you honest advice even if you decide not to use our services. Our goal is to help Montreal families breathe easier.
FAQ, Construction Dust and Air Quality in Montreal
Is construction dust really dangerous for children?
Yes, absolutely. Children’s lungs continue to develop through adolescence, making them more vulnerable to damage caused by fine particulate matter. Children also breathe faster than adults, so they inhale a proportionally greater amount of polluted air. Repeated exposure to construction dust can increase the risk of asthma, bronchitis, and other long-term respiratory problems. If you notice that your children are coughing more often or having breathing problems since a construction project began near your home, take this seriously and improve the air filtration in your home.
How can I tell if my ventilation ducts are contaminated with construction dust?
There are several telltale signs. If you see dust coming out of the vents when the system starts up, if you notice a visible buildup of dust around the vents, or if you smell dust or mold when the system is running, your ducts are likely clogged. A professional camera inspection can show you exactly what’s going on inside. At Vortex Air, we offer free inspections that often include photos of the inside of your ducts so you can see their actual condition.
Is a HEPA air purifier enough, or do I need to have my ducts cleaned as well?
The two approaches are complementary, not interchangeable. A HEPA air purifier filters the air in a room and captures airborne particles. This is excellent for improving air quality on a daily basis. But if your ducts are full of accumulated dust, your ventilation system will continue to circulate that dust every time it runs. The purifier will have to work twice as hard to compensate. The best approach: clean the ducts to eliminate the source of contamination, then use a HEPA purifier to maintain good air quality continuously.
How often should I have my ducts cleaned if I live near an active construction site?
Under normal conditions, having your ducts cleaned every 3–5 years is sufficient. However, if you are directly exposed to a major construction project lasting several months, you may need more frequent cleaning—possibly every 1–2 years for the duration of the project. Once the construction work is complete, have a thorough cleaning done to remove all buildup, then return to a normal maintenance schedule. This is an investment that protects your health and extends the life of your ventilation system.
What exactly does the CNESST say about crystalline silica in construction dust?
The CNESST classifies crystalline silica as a carcinogen and sets an exposure limit of 0.025 mg/m³ for workers over an 8-hour workday. Silica is generated by cutting, drilling, and sanding materials such as concrete, brick, and stone. Repeated exposure can cause silicosis, a serious and irreversible lung disease. Although these limits officially apply to workers, they highlight the seriousness of the hazard. If you live near a construction site where concrete is cut regularly, you are exposed to these same particles, albeit generally at lower levels.
How much does an air quality inspection cost in Montreal?
At Vortex Air, the basic inspection is free and comes with no obligation. We come to your home, assess your ventilation system, check the condition of your ducts (often with photos), and explain our findings to you. If you decide to proceed with a complete cleaning, the cost varies depending on the size of your system, typically ranging from 400 $ to 800 $ for an average Montreal home. It’s an investment that pays for itself through improved health, reduced medication costs, and greater efficiency of your heating and air conditioning system.
Is there anything I can do on my own, or do I really need a professional?
There are things you can do yourself: buy a HEPA air purifier, regularly replace your system’s filters, vacuum frequently with a HEPA vacuum cleaner, and seal visible air leaks around windows and doors. These measures really help. But for a deep clean of your ventilation ducts, you need professional equipment—specialized rotating brushes, industrial vacuums with HEPA filtration, and the expertise to avoid damaging your system. Trying to clean your ducts yourself with a household vacuum cleaner will just redistribute the dust without actually removing it.
The construction project next door will last another 6 months. What should I prioritize?
Start with immediate steps: buy at least one HEPA air purifier for the master bedroom and common areas. Keep the windows closed during peak construction hours. Use a HEPA vacuum cleaner to clean frequently. Next, have your ventilation ducts inspected; if you find that they’re already heavily clogged, have them cleaned now to prevent the problem from getting worse over the next 6 months. Once the construction is complete, perform a second thorough cleaning to remove any remaining buildup. This two-step approach protects you both during and after the construction work.
Construction dust is a serious problem in Montreal, but it doesn’t have to be. With the right knowledge, the right protective measures, and the help of qualified professionals when needed, you can protect your family and maintain good indoor air quality even if you live near an active construction site.
Don't let invisible dust affect the health of your loved ones. Take action now to create a healthier indoor environment.
Contact Vortex Air at 514-214-7492 (available 24/7) or visit vortexair.ca to schedule your free inspection. We'll help you understand your situation and implement the solutions that are right for your home. Protect Your Air Today , Your family deserves to breathe clean air.
