Ontario and Quebec · since 2005
Commercial Air Quality Testing in Ontario & Quebec
Commercial air quality testing starts with an inspector walking your building, then samples go to an accredited third-party lab and you get a written report you can hand to staff, tenants or an insurer. A mold air test is $550 plus tax with the outdoor sample included, asbestos is $430 for the first material, and the inspection report comes within 1 business day of the visit.
People in one part of the building keep saying the air is off, and you need an answer you can show them. We test air quality for commercial buildings of every kind: offices, schools, daycares, shops, restaurants, warehouses and rental buildings.
Since 2005 · 15,000+ inspections · IICRC certified inspectors
Commercial air quality testing at a glance
In one sentence: a certified inspector walks the building with you, samples the air or the suspect materials where the walk points, an accredited lab analyzes them, and you get a written report on mold, asbestos or formaldehyde with clear next steps.
Last updated: 6 November 2026
Complaints about a building’s air usually start with a smell or a headache
Someone on the third floor says the boardroom smells musty. Two people in the same corner get headaches by mid-afternoon. A tenant sends photos of a stained ceiling tile and asks what’s growing above it.
Some people call it sick building syndrome. The Canadian Centre for Occupational Health and Safety describes the pattern without the label: symptoms that show up a few hours into the workday and ease after people leave the building, or after a weekend away. When several people report the same thing, or they all work in the same area, the air is worth a look.
These are the calls we get most often from property managers, employers and landlords:
- A musty smell in one room or near the HVAC returns that cleaning doesn’t fix. If you can’t find the source, start with an odour inspection.
- Headaches, congestion or itchy eyes in one zone, easing after people leave.
- Water stains on ceiling tiles, drywall or window frames.
- A roof leak, flood or burst pipe, even one that seemed to dry out.
- Condensation in mechanical rooms or around rooftop units.
- A renovation coming up in a building from before 1990.
- A tenant or staff complaint that needs a written answer.
- New flooring, furniture or millwork and a chemical smell that won’t fade.
But no air test can prove a building’s air is safe
Health Canada’s guidance for indoor air quality professionals says it doesn’t recommend routine mold air testing in offices, schools or other non-industrial buildings, and that decisions should rest on a thorough building inspection. It also names the cases where sampling helps: when mold is suspected but an inspection hasn’t found the source, and to compare the air before and after cleanup.
The rules work the same way. Ontario has no stand-alone indoor air quality rule for offices. Employers must take every reasonable precaution to protect workers, and offices must be adequately ventilated. The Ministry of Labour’s alert on mould in workplace buildings says sustained or extensive visible mould on interior surfaces is unacceptable. In Quebec, the workplace health and safety regulation requires adequate ventilation, a yearly inspection of mechanical ventilation, and at least 20% relative humidity in offices during business hours.
Myth One air sample tells us whether the building is safe.
Fact A sample shows what was in the air in one spot during a few minutes. It answers a question the inspection raised. It can’t clear the whole building.
Myth There’s a legal mold limit for Canadian offices.
Fact There isn’t one. Lab results are read against the outdoor sample taken the same day, and visible growth indoors is a problem whatever the count says.
Myth A cheap monitor on the wall does the same job.
Fact A monitor tracks trends like humidity. It can’t name a mold type, find asbestos in a ceiling tile or give you a lab report with a chain of custody.
So we inspect the building first, then sample where the walk points us
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1
Before the visit
We ask what people are noticing
Where the complaints come from, when they started, what’s changed in the building, and when the last leak or renovation happened. That decides the scope, so you only pay for samples that answer a question.
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2
Day of the visit
A walk through the building with your facility lead
The inspector checks the complaint areas, ceiling spaces, HVAC returns and mechanical rooms, takes moisture and humidity readings during normal occupancy, and flags any suspect building materials.
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3
Day of the visit
Samples where the walk points
Air samples in the complaint zones plus one outdoor sample for comparison, bulk samples of suspect materials, or a formaldehyde badge. Everything is logged by location and sealed for the lab.
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4
Within 1 business day, then lab results
A written report, then the lab numbers
The inspection report covers what the inspector found and where. Lab results follow (mold 2 to 5 business days, asbestos 3 to 4), and we explain them in plain language. See what to expect during an inspection.
Tell us about the building and we’ll tell you what to sample.
Where the walk points decides the commercial test: mold, asbestos or formaldehyde
We keep the list short on purpose. These three cover most of the problems we find in Ontario and Quebec buildings, and each one has a lab method that gives you a clear answer.
Mold
Air samples in the complaint zones compared with outdoor air, plus surface samples where there’s visible growth. The lab names the mold types and counts them. More on our mold testing.
Asbestos
Bulk samples of ceiling tiles, floor tile and mastic, drywall joint compound, pipe wrap and plaster, analyzed under a microscope. More on our asbestos testing.
Formaldehyde
A lab badge hung for 24 to 48 hours after new flooring, furniture or millwork, measured against Health Canada’s formaldehyde guideline.
Which spots we check first depends on how the commercial building is used
These are the patterns our inspectors see again and again.
Offices
Damp ceiling spaces after a roof or plumbing leak, condensation at HVAC returns, and asbestos in older fit-outs that are about to be renovated.
Schools and daycares
Older floor tile and pipe wrap that may contain asbestos, and mold around aging windows and in portables. Parents and boards usually ask to see the lab results.
Rental and condo buildings
Mold that moves between units through shared walls, and complaints that need a neutral written answer for the owner and the tenant.
Restaurants and retail
Wet walls behind dish pits and coolers, and staff complaints near the kitchen or the back of the store.
Warehouses and light industrial
Asbestos in older structures before a mezzanine or office build-out, and mold where loading doors and roof leaks let water in.
Clinics and dental offices
Mold after a leak in a space that has to stay open, and asbestos checks before a reno in an older medical building.
But a renovation changes the order: asbestos testing comes before the tools
Under section 30 of Ontario’s Occupational Health and Safety Act, the owner of a construction project has to find out which designated substances are on site before work starts and give that list to the contractors. A designated substance survey is the usual way owners get it. Asbestos is one of the 11 substances on Ontario’s list.
For asbestos itself, Ontario Regulation 278/05 has a building owner get the suspect materials examined and a written report before demolition, alteration or repair, and pass it to the contractor. A material counts as asbestos-containing at 0.5% or more by dry weight. In Quebec, employers must inspect buildings built before 15 February 1990 for sprayed-on asbestos and before 20 May 1999 for asbestos heat insulation, keep a register, and treat a material as asbestos-containing unless a lab report shows otherwise. A visual check isn’t proof.
What we cover, and what we don’t. We sample and test the asbestos. Lead paint, mercury, silica and the other designated substances are outside what we test, so a full survey of all 11 needs an environmental consultant, and our asbestos report can go into it. We don’t do asbestos abatement or removal, so our results don’t depend on who gets the job afterward.
In a commercial building, the air sample is rarely where we start. We walk the ceiling spaces, the returns and the room people complain about first. Then we sample where the walk points, so the lab is answering a real question.
Luka Markovic
Senior Indoor Environmental Inspector and Engineer · Certified Mold Inspector (CMI) · Master of Mechanical Engineering
Either way, commercial air quality testing cost depends on the samples, not the square footage
We charge per sample, plus tax. The inspector’s visit, the lab analysis and the written report are inside the price, and you get the total in writing before any sampling starts.
| Service | Price (CAD, plus tax) | What’s included | Best for |
|---|---|---|---|
| Mold air test | $550 | Inspection, 1 indoor air sample, a free outdoor sample, lab analysis, written report | One complaint area |
| Each extra air sample | $260 | Another room or zone sampled in the same visit | Several floors, suites or zones |
| Asbestos, first material | $430 | Sampling, accredited lab analysis, written report | One suspect material before a renovation |
| Asbestos, each extra material | $250 | Another material sampled in the same visit | Fit-outs that touch ceilings, floors and walls |
| Formaldehyde | $350 with a visit, $595 on its own, $295 per extra room | Lab badge, 24 to 48 hours on site, lab analysis | New flooring, furniture or millwork |
| Visual inspection only | $95, written report $155 extra | A walk through with an inspector, no lab samples | A first look before you decide on testing |
One complaint area
A musty boardroom, with the outdoor sample included.
Typical office complaint
Three indoor air samples across the zones where people report symptoms.
Before a renovation
Three suspect materials: a ceiling tile, a floor tile and joint compound.
A multi-floor building is priced the same way, so the total depends on how many zones and materials need answers. Call 1-866-528-2897 and we’ll work out the number with you. For how these prices compare across Canada, read our guide to air quality testing cost.
What commercial clients say
Real feedback from recent commercial inspections across Ontario and Quebec
"Two of our staff started complaining about headaches and that 'something smelled off' in the boardroom. The inspector found mold growth behind the HVAC return and caught it before our lease renewal walkthrough. Defensible report I could hand to the landlord."
"We needed asbestos clearance before rebuilding the mezzanine in our older warehouse. They came in, pulled bulk samples the same week, and gave us a written compliance summary in five business days. Insurer accepted it without follow-up."
"Three line cooks were getting headaches every shift. They sampled behind the dish-pit wall and found grease-trap mold and a cracked makeup-air return. Numbers I could share with my insurer. Problem solved before health inspection."
"We were renovating a 1960s wing of the school. Asbestos clearance was non-negotiable. Parents wanted to see actual lab results. Their report was so clear we presented it at the next board meeting. No questions, no callbacks. Will use again for the next phase."
Even a clean report has limits, and we’d rather say so up front
A report answers for the places and materials we sampled, on the day we sampled them. If we test the third floor, it says nothing about the basement, and a ceiling tile that tested negative doesn’t clear every tile installed in a different decade. That’s why we agree on the scope before we start.
Testing also doesn’t explain every symptom. CCOHS notes that headaches and fatigue at work can come from colds, noise, lighting, temperature or stress. If the report comes back clean and people still feel unwell, the next step may be a ventilation contractor or an occupational health professional, not more air samples.
And testing doesn’t fix anything. If we find mold or asbestos, the report says where and what to do next, and a qualified contractor does the work. Health Canada’s guidance advises deciding in advance who will identify, hire and oversee that work, so conflicts of interest are managed. Our samples go to an accredited third-party lab, so the analyst reading them has no stake in what happens after.
We test commercial buildings across Ontario and Quebec
For local detail, see air quality testing in Ottawa, Montreal, Toronto, York Region and Durham, Mississauga and Peel and Oakville, Halton and Hamilton, plus asbestos testing in Ottawa, asbestos testing in Toronto, asbestos testing in Montreal and mold testing in Ottawa. Testing a house instead? Our home air quality testing page covers it, and every option is on our air quality testing services page.
Commercial air quality testing questions we hear most
Start with an inspection, not a sample. An inspector walks the complaint areas, the ceiling spaces and the HVAC returns with your facility lead, then samples the air or the suspect materials where the walk points. Samples go to an accredited lab, and you get a written report. Health Canada says decisions about mold in offices should rest on a thorough building inspection, with sampling used when the source hasn’t been found. Here’s what to expect during an inspection.
With us, a mold air test is $550 plus tax with the inspection, one indoor sample, a free outdoor sample and the report included, and each extra sample is $260. Asbestos is $430 for the first material and $250 for each extra. Formaldehyde is $350 added to a visit. A typical office complaint with three indoor samples comes to $1,070, and you get the total in writing before sampling starts.
A monitor on the wall is fine for watching humidity and trends. It can’t name a mold type, find asbestos in a ceiling tile or give you a lab report with a chain of custody, and that’s what a tenant, a board or an insurer usually asks for. If there’s a complaint to answer or a renovation to plan, use an inspector and an accredited lab. Our guide to air quality testing kits covers the monitors.
Not as a single number. Ontario requires employers to take every reasonable precaution to protect workers and requires offices to be adequately ventilated, and the Ministry of Labour says sustained or extensive visible mould on interior surfaces is unacceptable. There’s no legal mold count for offices, so lab results are read against the outdoor sample taken the same day.
Usually, yes. In Ontario, a project owner has to list the designated substances on site, asbestos included, before work starts, and Regulation 278/05 has an owner get suspect materials examined and a written report before demolition, alteration or repair. In Quebec, employers must inspect buildings built before 1990 and 1999 for certain asbestos materials and keep a register. We sample and test the asbestos part.
The inspection report comes within 1 business day of the visit. Lab results follow: mold in 2 to 5 business days, asbestos in 3 to 4, and formaldehyde in about 2 weeks. Rush analysis is available for an added fee. If you have a lease date or a contractor start date, tell us when you call and we’ll plan around it.
It’s worth keeping the two separate. Health Canada’s guidance for indoor air quality professionals advises deciding in advance who will identify, hire and oversee any mold or asbestos work, so conflicts of interest are managed. Our samples go to an accredited third-party lab, and we don’t do asbestos abatement or removal, so the results don’t depend on who gets the job afterward.
People keep saying the air is off?
Get an inspector through the building, samples read by an accredited lab, and a written answer you can share. We test, you decide what happens next.
Phone open 24/7 · Inspections Monday to Friday, 8 AM to 5 PM · Response within 1 business day