If you live in Notre-Dame-de-Grâce, you’ve probably noticed it: the air seems heavier on some days, especially when traffic picks up on Sherbrooke or when smoke from forest fires comes back to haunt us every summer.
Your nose is itchy, your kids are coughing more often, and you're wondering if it's just you or if things really are worse than they used to be.
The truth? It’s not just in your head. Air quality in NDG has deteriorated in recent years, and fine particulate matter (PM2.5) levels in the neighborhood now stand at 15.7 μg/m³—well above the recommended health limits, especially for children and people with asthma.
But here’s the good news: there are practical, affordable solutions to improve the air you breathe at home. No miracles—just proven methods we’ve been using for 10 years to help families like yours throughout Montreal.
Why Air Quality in NDG Is Rapidly Deteriorating in 2025
NDG is not immune to the air quality problems affecting Montreal. Between heavy traffic, increasingly frequent wildfire alerts, and old, poorly ventilated buildings, the neighborhood faces a combination of factors that directly affect your health.
It's not just a matter of comfort. We're talking about real respiratory problems, allergies that are getting worse, and rising energy bills caused by poorly functioning ventilation systems.
Traffic-Related Pollution Around Sherbrooke & Décarie
Sherbrooke Boulevard and the Décarie Interchange are among the busiest thoroughfares in Montreal. The result? Nitrogen dioxide (NO₂) levels in NDG hover around 25 to 30 ppb (parts per billion).
For children and people with asthma, this is enough to trigger symptoms. The CIUSSS Ouest-de-l’Île has, in fact, noted an increase in medical visits related to respiratory problems in the area, particularly near major thoroughfares.
Fine particles from traffic seep into homes, especially those with older or poorly insulated windows. You can see it on your furniture—that thin layer of gray dust that keeps coming back.
Impact of Wildfires and Air Quality Alerts
The summer of 2025 was brutal. In July, the air quality index (AQI) in Montreal rose above 150 for several consecutive days. In NDG, as elsewhere in the city, emergency room visits for asthma attacks doubled during those periods.
The City of Montreal has issued alerts recommending that people stay indoors, but if your ventilation system isn't adequate, you'll still be breathing in smoke that seeps in through doors, windows, and even poorly sealed ducts.
This isn't a problem that's going to go away. Experts predict that these episodes of smoke will become more frequent and more intense in the coming years.
Ventilation Problems in NDG Housing (Winter + Older Buildings)
NDG is a beautiful neighborhood with its own unique charm, tree-lined streets, and historic buildings. But these old buildings often have outdated ventilation systems—or none at all.
Only 35 % of the homes in the neighborhood have adequate ventilation according to current standards. What does that mean in practical terms? Stagnant, stale air, accumulated moisture, and levels of volatile organic compounds (VOCs) that are 45 % higher than the Canadian average.
Winter is even worse. We close everything up to keep the heat in, but we also trap all the pollutants inside: dust, allergens, cooking odors, household cleaning products, and invisible mold.
Quick and Effective Solutions for Improving Indoor Air Quality in NDG
You don’t need to tear down your apartment or spend thousands of dollars to breathe easier. There are solutions that really work, tailored to the reality of NDG—whether you’re a tenant in a three-and-a-half on Monkland or the owner of a duplex near NDG Park.
Here’s what we recommend to our customers based on 10 years of experience and more than 500 service calls in the Montreal area.
HEPA Air Purifiers — The First Line of Defense Against PM2.5 and Smoke
HEPA (High Efficiency Particulate Air) filters capture 99.97% of particles 0.3 microns and larger. This includes fine particles from traffic, wildfire smoke, pollen, mold spores, and dust mite allergens.
In Quebec, only 22 % of households use an air purifier. In NDG, the figure is estimated to be slightly higher—about 28 %—likely due to the proximity to traffic and a population that is more aware of health issues.
A good HEPA air purifier costs between 150 $ and 400 $, depending on the size of the room. It’s an investment that pays for itself quickly when you consider the doctor’s visits you’ll avoid and the nights of restful sleep you’ll gain.
How to Choose a Model Suitable for NDG Apartments
Look for a CARB (California Air Resources Board)-certified unit with an ozone emission rate of less than 0.05 ppm. This ensures that your air purifier doesn't create new pollutants while trying to clean the air.
If you want to take it a step further, models with IoT sensors (such as AirThings) let you monitor air quality in real time on your phone. You can see exactly when particle levels rise and adjust accordingly.
For a typical NDG apartment (800 to 1,000 sq. ft.), a unit with a CADR (Clean Air Delivery Rate) of at least 200 is sufficient for the main room.
Improving Ventilation (HVAC) — Essential in Winter
Ventilation is the key to success. Without adequate air exchange, even the best air purifier can't work miracles.
In Quebec, the standard recommends a minimum of 0.35 air changes per hour (ACH). Most older buildings in NDG fall far short of that, especially in winter when everything is tightly sealed.
Professional cleaning of your ventilation ducts can reduce VOCs by up to 60 %. We saw this in a pilot project we conducted last year in a building in NDG: after a thorough cleaning of the HVAC system and the installation of MERV-13 filters, VOC levels dropped by 25 %.
The landlords told us that their tenants were breathing easier, had fewer allergies, and that complaints about musty odors had completely disappeared.
Get a free air quality assessment in NDG
Signs of Poor Air Quality in NDG Buildings
How can you tell if your ventilation system is inadequate? Here’s what we’ve observed among our customers:
Relative humidity drops below 40 % in winter, which dries out the mucous membranes and makes it easier to catch viruses. You’ll see condensation on the windows, a sign that humid air isn’t being properly vented. Cooking odors linger for hours, even with the windows open.
If you notice at least two of these signs, your ventilation system needs attention.
Waterproofing and Sealants to Prevent Smoke from Forest Fires
When smoke from wildfires drifts in, it seeps everywhere. Without proper sealants, up to 70 % of outdoor smoke can enter your home.
The good news? For less than 100 $, you can make a big difference with simple solutions: weatherstripping around doors and windows, door sweeps, and caulk for cracks around the frames.
It's a basic DIY project that anyone can do on a Saturday afternoon. Or, if you prefer, we can take care of it during a comprehensive inspection of your ventilation system.
Advanced solutions for families, people with asthma, and older apartments
If you have children with asthma, if someone in your family suffers from severe allergies, or if you live in one of the older apartment buildings near the Loyola Campus, basic solutions may not be enough.
Here are our recommendations for taking further steps to improve your air quality.
Humidity control (40–60 %) to limit spores and irritants
The ideal relative humidity is between 40 and 60 %. Below 40 %, your mucous membranes dry out and you become more susceptible to infections. Above 60 %, you create the perfect environment for mold and dust mites.
In Montreal during the winter, it’s common for humidity levels to drop below 30 % due to heating. A portable humidifier can solve the problem, but be careful: if your ventilation is poor, you risk causing condensation and mold problems.
There have been cases where mold spores in the air have dropped by 80 % simply by adjusting the humidity and improving air circulation. This is particularly important in basements and windowless bathrooms.
Talk to a QAI expert about your NDG home
MERV-13 filters for existing units (furnaces, air handlers)
If you have a central heating system or an air exchanger, replacing your standard filters with MERV-13 filters can make a huge difference.
MERV-13 filters capture fine particles, bacteria, and even some viruses. These are the filters that were widely installed in commercial buildings during the pandemic, and they work just as well in homes.
The catch? Many residential systems aren't designed for filters this dense. This can reduce airflow and force your system to work harder. We always assess your system's capacity before recommending this type of filter.
For tenants, unfortunately, this improvement depends on the landlord. But it’s worth bringing up, especially if several tenants have respiratory problems.
IAQ Sensors and Real-Time Monitoring
Air quality sensors skyrocketed in popularity after the June 2025 wildfires. Adoption surged by 20 % in just a few weeks.
These small devices measure fine particulate matter (PM2.5 and PM10), VOCs, CO2, humidity, and temperature. You can see in real time what’s happening in the air around you.
In NDG, typical VOC levels measured in homes range from 0.5 to 1.2 mg/m³. At levels above 1.5 mg/m³, symptoms begin to appear: headaches, eye irritation, and fatigue.
A good sensor costs between 150 $ and 300 $. It's an excellent addition to a HEPA air purifier because you know exactly when to turn it on.
Common Myths About Air Quality — and What the Experts Say
We hear all kinds of advice about air quality. Some of it is good, while other advice is downright dangerous. Here’s what we regularly sort through with our clients.
«Just opening the windows is enough» — Not true in the case of smog in NDG
Opening the windows is great… when the outside air is clean. But when the IQA exceeds 25, you’re letting in more pollution than you’re letting out.
During forest fire alerts or days with heavy smog, keep your windows closed and rely on your mechanical ventilation system and air purifiers.
The right thing to do? Check the IQA before opening a window. Many weather apps now display it, or you can check the City of Montreal’s website.
«Plants purify the air enough» — effect
This is probably the most persistent myth. Yes, some plants absorb trace amounts of pollutants. But the effect is so minimal that it’s practically nonexistent.
A frequently cited NASA study showed that certain plants could filter the air… in a completely sealed laboratory environment. In a real home, you would need about 10 plants per 100 square feet to see a measurable effect.
Plants are beautiful and good for your mood, but don't count on them to purify your air.
«Air purifiers produce harmful ozone»
This used to be true for some older models, especially those with UV lamps or ion generators. But modern CARB-certified HEPA purifiers emit virtually no ozone (less than 0.05 ppm).
There is no risk of radiation or side effects with a high-quality device. We always recommend checking for CARB certification before purchasing.
How to Apply These Solutions to Your NDG Situation
NDG is diverse. You’ll find new condos near Monkland Village, century-old apartments in Côte-Saint-Luc, and family-friendly duplexes near NDG Park. Each situation calls for a slightly different approach.
Here's how to adapt these solutions to your specific situation.
For tenants (solutions that do not require building modifications)
You're not allowed to modify the ventilation system? No problem. You can still significantly improve your indoor air quality.
A portable HEPA air purifier in your bedroom and living room can make a huge difference. Add draft stoppers and door sweeps to keep drafts out. Invest in a good humidifier if the air is too dry in the winter.
Regular Cleaning of Your Wall-Mounted Units (if you have a wall-mounted air conditioner) is also within your control. Most homeowners never do this, but that’s often where dust, mold, and bacteria accumulate and contaminate your air.
Wall-mounted unit cleaning starting at 99 $ — Book online
For homeowners (structural improvements)
If you're a homeowner, you have more options. Start by having your entire HVAC system inspected: ducts, air exchanger, filters, and airtightness.
Professional duct cleaning every 3 to 5 years removes years of accumulated dust, allergens, and debris. We’ve seen ducts in NDG so clogged that airflow was reduced by half.
Switch to MERV-13 filters if your system allows it. Improve the airtightness of the building envelope, especially around doors and windows. These investments will also reduce your heating and cooling costs.
For families and children with asthma
Children breathe faster than adults and are closer to the ground, where heavy particles settle. If your child has asthma, good air quality isn’t a luxury—it’s a medical necessity.
Focus your efforts on the bedroom first. A HEPA air purifier that runs overnight can dramatically reduce nighttime attacks.
Avoid scented household products, candles, and air fresheners that release VOCs. Vacuum with a HEPA filter at least twice a week.
If the symptoms persist despite these measures, request a thorough inspection. There may be a hidden source of contamination: mold in the walls, ducts that have never been cleaned, or poor ventilation in the bathroom.
Why Choose a Local Expert to Assess Your Air Quality
We could sell you a whole lot of equipment and promise you miracles. But the reality is that every situation is unique.
What works in a new condo on the Plateau won't necessarily work in a 1920s apartment in NDG. That's why we always start with a free inspection.
Knowledge of the NDG micro-context (traffic, older buildings, density)
We've been working in NDG for years. We're familiar with the neighborhood's specific challenges: the nearby traffic on Sherbrooke, the typical building construction, and the outdated ventilation systems.
We know where to look for problems because we’ve seen them hundreds of times before. Ducts running through damp basements. Wall-mounted units that haven’t been cleaned since they were installed. Improperly adjusted air exchangers that waste energy without renewing the air.
Identification of Invisible Sources (VOCs, Bioaerosols, Spores)
A stuffy nose or a persistent cough is never just «normal.» There’s always a reason.
Sometimes it’s obvious: a dryer vent full of lint that poses a fire hazard. Other times, it’s more subtle: mold spores in the ventilation system, VOCs escaping from old building materials, or an air exchanger that circulates stale air instead of bringing in fresh air.
We have the tools and experience to identify these hidden sources. No guesswork—just a methodical and honest analysis of your situation.
Transparent inspection process + detailed report
Our free inspection is truly free. No surprises, no pressure to buy anything.
We'll come to your home, assess your entire system, and discuss your concerns and symptoms. Then we'll provide you with a clear report that includes photos, explanations, and our recommendations.
If your system is in good condition, we'll let you know. If it needs cleaning or repairs, we'll explain why and how we'll proceed. Our prices are transparent, and our INVC-certified technicians follow strict protocols.
Schedule an IAQ inspection in NDG now — 514-214-7492
FAQ — Frequently Asked Questions About Air Quality in NDG
How can I tell if my indoor air is contaminated in NDG?
The most common signs: you cough more often at home, your allergies are worse in the winter, you have headaches in the morning, and a fine layer of gray dust keeps reappearing on the furniture.
If you notice musty odors or if the air feels heavy and stuffy, that’s a clear sign that your ventilation system isn’t working properly. An air-quality sensor can provide you with accurate data, but often your body already tells you.
What is the best air purifier for wildfires in Quebec?
Look for a unit with a genuine HEPA filter (not «HEPA-type») that is CARB-certified to prevent ozone emissions. The CADR should be appropriate for the size of your room: at least 200 for a bedroom, 300+ for a living room.
Models with built-in sensors are convenient but cost more. If you're on a tight budget, a good basic HEPA purifier costing 150–200 $ does the job just fine during smoke alerts.
Do older buildings in NDG have poor ventilation?
Often, yes. Many buildings constructed before 1980 do not have a mechanical ventilation system. They rely on natural air infiltration, which no longer works once the windows are replaced with airtight models.
Even those with newer systems often suffer from a lack of maintenance: ducts that have never been cleaned, filters that are changed too infrequently, and improperly calibrated air exchangers.
Are IAQ sensors reliable?
Good models, yes. Look for well-known brands such as AirThings, Awair, or Purple Air. They measure fine particles, VOCs, CO2, and humidity with a level of accuracy that’s acceptable for residential use.
They are not a substitute for a professional test for specific issues such as mold or radon, but they provide an excellent day-to-day snapshot of your air quality.
How can we protect children with asthma during air quality alerts?
Keep them indoors when the indoor air quality (IQA) index exceeds 50. Run a HEPA air purifier in their room at all times. Avoid any activities that increase indoor pollution: no grilling, no candles, and no strong household cleaning products.
If your child develops symptoms despite these precautions, have your ventilation system inspected. Smoke may be seeping in through the ducts, or there may be airtightness issues that you can't see.
When should you open the windows in NDG without making air pollution worse?
Always check the IQA before opening a window. If it’s below 25, you can open the window without worry. If it’s between 25 and 50, open the window briefly to let in fresh air, but not all day long. If it’s above 50, keep the window closed and rely on your mechanical ventilation system.
Early in the morning (before 7 a.m.) and late at night (after 9 p.m.), the air quality is generally better in NDG because traffic is lighter. These are the best times to air out your home if you live near Sherbrooke or Décarie.
Air quality in NDG is a real challenge, but it’s far from inevitable.
With the right solutions tailored to your situation—whether you’re a renter, a homeowner, a parent of children with asthma, or simply someone who wants to breathe easier at home—you can make a real difference.
At Vortex Air, we’ve been helping families in NDG and throughout Montreal breathe more easily for over 10 years. We know the challenges of the neighborhood, we understand the typical building construction, and we know exactly where to look for problems.
Our team of certified technicians works 7 days a week, from 7 a.m. to 9 p.m. We offer free, no-pressure inspections and transparent pricing.
Book your free evaluation now — call 514-214-7492 or visit vortexair.ca
Breathe better. Live better. Start today.
