Home / Air Quality Testing

Asbestos Air Quality Testing

Air quality testing measures whether asbestos fibers are currently present in the air of a space — used for post-abatement clearance, ongoing occupied-building monitoring, and situations where a disturbance may already have occurred.

When You Need Air Testing (vs. Bulk Sampling)

If you haven’t disturbed anything yet and want to know whether it’s safe to start a project, bulk sampling is almost always the right first step. Air testing becomes necessary when:

Abatement or removal work has just been completed and the space needs to be cleared before reoccupancy
A disturbance (planned or accidental) may have already released fibers and you need current air-quality data
A building is occupied and ongoing monitoring is part of a facility’s risk management

PCM vs. TEM: What's the Difference?

PCM — Phase Contrast Microscopy

Counts fibers in an air sample but cannot definitively distinguish asbestos fibers from other fiber types. It’s faster and less expensive, and is the standard method for many clearance and monitoring situations.

TEM — Transmission Electron Microscopy

Can positively identify asbestos fiber types at a much higher resolution. It’s more expensive and takes longer, but it’s the method typically required for the most rigorous clearance situations, particularly post-abatement clearance in sensitive occupancies.

Which method is appropriate depends on the situation — this is worth discussing directly rather than defaulting to one or the other, since using TEM when PCM is sufficient adds unnecessary cost, and using PCM when TEM is required means redoing the test.

What Happens During a Clearance Test

If you’ve had abatement or removal work done by any contractor, air clearance testing before reoccupying the space is standard practice and often required. We arrive after the abatement contractor’s own final cleanup and set up one or more calibrated air pumps inside the work area, typically alongside a background sample taken outside the containment area for comparison. Each pump draws a measured volume of air through a filter over a set collection period. The area generally needs to stay unoccupied and undisturbed until sampling is complete and results confirm clearance — opening up the space early, before results are back, defeats the purpose of testing in the first place. Our clearance results are based solely on independent lab analysis, giving you a read that isn’t dependent on the abatement contractor’s own assessment of their work.

Understanding Fiber Counts

Air lab results are reported as a fiber count — the concentration of fibers measured per cubic centimeter of air sampled. This is why air testing answers a different question than bulk sampling: a bulk sample tells you whether a material contains asbestos at all, while a fiber count tells you how much, if any, is actually airborne in a given space at the time of sampling. Your result is compared against the clearance or exposure threshold relevant to your specific situation — which varies depending on the type of occupancy and the regulatory context of the project — and we’ll walk you through what your specific number means rather than leaving you to interpret a lab printout on your own.

Who Typically Requires Air Testing

Air testing shows up at several points outside of a straightforward clearance test. Abatement contractors generally need an independent clearance result before they can release a work area back to the property owner. Property managers and building owners use it to confirm a space is safe to reoccupy after any known disturbance. Schools, daycares, and similar occupancies tend to apply a higher standard of caution given the population involved. Landlords and commercial tenants sometimes need it during buildouts in older structures, and lenders or insurers occasionally request documentation as part of due diligence on a property with a known asbestos history.

Occupied-Building Monitoring

Not every air test follows a disturbance. Buildings that manage asbestos-containing material in place, rather than removing it — a common approach for materials in good condition that would cost more to remove than to monitor — often use periodic air sampling as part of an ongoing operations and maintenance plan. The goal is confirming the material remains undisturbed and fiber levels stay where they should be, catching a problem early rather than waiting for a renovation to reveal it. This is more common in older commercial and institutional buildings than in single-family homes; see our Commercial Testing page for more on how operations and maintenance plans work.

Process, Equipment, and Turnaround

Air sampling uses a calibrated pump to draw a measured volume of air through a filter over a set period, which is then sent to an accredited lab for PCM or TEM analysis. PCM results are typically available faster than TEM, given the difference in analysis complexity; exact turnaround depends on lab volume and whether rush processing is requested.

Frequently Asked

Do I need air testing if I already did bulk sampling?

Not necessarily — they answer different questions. If bulk sampling confirmed no asbestos-containing materials, air testing usually isn’t needed for that project. Air testing becomes relevant specifically around disturbance, abatement clearance, or ongoing occupied-space monitoring.

How long does air quality testing take?

Sample collection typically takes under an hour once equipment is set up. PCM lab results are usually available faster than TEM, given the difference in analysis complexity.

Is air testing required by law in Montana?

Not a blanket legal requirement the way pre-renovation inspection is, but it’s standard practice — and often required by the abatement contractor or building owner — before reoccupying a space post-abatement.

What counts as a passing result?

Clearance thresholds vary by method and jurisdiction requirement. We’ll explain what your specific result means and whether it meets the clearance standard relevant to your project.

Does a building need ongoing air testing if it has asbestos-containing material?

Only if that material is being managed in place rather than removed. Buildings with an operations and maintenance plan often use periodic air sampling to confirm the material remains undisturbed, which is different from a one-time clearance test tied to a specific renovation or abatement event.

Who typically orders air testing — me or my abatement contractor?

Either, but for clearance testing it’s worth using an independent tester rather than relying solely on your abatement contractor’s own results, since clearance is meant to be a check on their work, not a self-certification.

Schedule Air Quality Testing

Call or fill out the form — we’ll help determine whether PCM or TEM is right for your situation.