How Long Does Asbestos Stay in the Air?
“The duration asbestos fibers remain airborne depends on factors like fiber size and disturbance method – smaller fibers under 5 microns can stay suspended for weeks, while larger fibers settle in hours. More aggressive mechanical release causes longer airborne times than low-impact disturbance, but there are no exact rules for how long asbestos stays airborne after release.”
Asbestos refers to a group of naturally occurring fibrous silicate minerals that were commonly used as fireproofing and insulation material in buildings constructed before the 1970s.
When asbestos-containing materials are disturbed or damage, microscopic fibers can be released into the air. Inhaling these asbestos fibers over time can lead to serious health issues like lung cancer and mesothelioma.
Knowing how long these fibers stay airborne once released is important for limiting exposure risk. This post provides an overview of the factors that influence how long asbestos can remain suspended in the air after release.
Why Asbestos is Dangerous
Asbestos fibers are made up of microscopic bundles that can easily be inhaled into the lungs. According to the Environmental Protection Agency (EPA), the fibers are resistant to heat and most chemicals and do not readily dissolve. This allows them to remain in the lungs for long periods of time after inhalation.
The EPA notes that asbestos fibers lodged in the lungs can cause lung tissue scarring and shortness of breath. The fibers can also cause mesothelioma, a rare cancer that affects the thin membranes lining the lungs, chest, abdomen, and heart.
The amount of time between asbestos exposure and the onset of disease can be 20 years or more. This long latency period means asbestos-related health issues may not arise until decades after initial exposure. The EPA warns that there is no safe level of asbestos exposure and the more asbestos fibers inhaled, the greater the risk of disease.
What Determines How Long Asbestos Stays Airborne?
When released into the air, some asbestos fibers will rapidly fall out and settle on surfaces while others can remain suspended indefinitely. The duration airborne depends on several key factors:
Fiber Size and Type
- Larger and heavier fibers settle faster: Chunkier fibers above 5 microns in size tend to fall out of the air more quickly, within hours in calm air.
- Thinner fibers stay suspended longer: Extremely tiny asbestos fibers less than 5 microns can remain airborne for weeks if air is constantly disturbed. Some fibers are so small they never settle.
- Amphibole asbestos suspends longer: There are two major types of asbestos – amphibole and chrysotile. Amphibole asbestos fibers are thinner and more durable, remaining airborne longer than chrysotile.
Amount of Asbestos Released
- The greater the amount of asbestos disturbance and damage, the higher the fiber levels will be in the air initially.
- More release means it will take longer for air concentrations to drop as fibers gradually settle over time.
- Calm indoor air with no ventilation allows asbestos fibers to remain suspended for longer durations.
- Higher air flow from ventilation systems or outdoor windy conditions will help dissipate fiber-containing air more rapidly.
- Aggressive mechanical damage like sanding or breaking apart asbestos materials will release far more fibers than low-impact damage.
- More forceful disturbance causes longer suspension times from the sheer number of fibers released.
Estimated Suspension Times
While it’s not possible to provide exact rules on how long asbestos stays airborne, some general estimates based on fiber size and disturbance intensity can help guide expectations:
Heavier fibers >5 microns
- Settle within hours in calm air
- Settle within minutes if outdoors in windy conditions
Smaller fibers <5 microns
- Can remain airborne for weeks if air is constantly disturbed
- May never settle in extreme cases
Major fiber release (e.g. breaking apart insulation)
- Significant airborne fiber presence for 48 hours or more
- Elevated levels for weeks in confined space
Low-impact disturbance (e.g. bumping intact material)
- Air concentration drops considerably after a few hours
- Undetectable suspension beyond 24 hours
These timeframes will vary substantially based on specific conditions. But in general, the more contained and gentler the asbestos disturbance, the shorter the duration of airborne fibers. Vigorous mechanical damage causes the most extreme and lasting fiber release into the air.
Recommendations for Minimizing Exposure
Given the severe long-term health risks associated with inhaling asbestos, it’s critical to avoid disturbing asbestos-containing materials and to minimize exposure when accidental release occurs:
- If you suspect asbestos has been released into the air, leave the area immediately until it can be properly cleaned. Do not bump, brush, or otherwise disturb the release area further once identified.
- If possible, isolate the release area using plastic sheeting until professional asbestos abatement personnel can contain the scene. Turn off fans or ventilation systems connected to the area.
- If you believe you inhaled asbestos fibers, contact your doctor to discuss being examined and monitored for symptoms. Fiber inhalation does not always lead to disease, but early evaluation is advised.
- When renovating or demolishing older buildings constructed before 1980, have building materials professionally inspected for asbestos content before commencing work.
- If asbestos is present, hire accredited professionals to remove it safely following asbestos abatement procedures. Do not attempt do-it-yourself asbestos removal. Disturbance must be minimized.
- For low-level asbestos exposure situations like remodeling projects, use protective equipment like respirators and disposable coveralls. Improve ventilation and use air filtration devices equipped with HEPA filters designed to trap asbestos fibers.
Carefully following occupational safety regulations and taking precautions when dealing with older buildings can help reduce the risk of inhaling airborne asbestos fibers.
Be especially cautious when conducting activities like insulation removal, demolition, sanding walls and ceilings, or dismantling building components. Assume asbestos is present in doubtful cases until verified otherwise.
Remaining mindful and vigilant about the materials being disturbed will help minimize exposure and associated adverse health effects.
1. How long does asbestos stay in the air?
The duration asbestos fibers remain airborne depends on factors like fiber size and disturbance method. Smaller fibers under 5 microns can stay suspended for weeks, while larger fibers settle in hours. More aggressive mechanical release causes longer airborne times than low-impact disturbance, but there are no exact rules for how long asbestos stays airborne after release.
2. Why is asbestos dangerous?
Asbestos fibers, when inhaled, can cause serious health issues like lung cancer and mesothelioma. These microscopic fibers are resistant to heat and chemicals, allowing them to remain in the lungs for long periods and potentially leading to lung tissue scarring, shortness of breath, and even mesothelioma.
3. What factors determine how long asbestos stays airborne?
The duration asbestos fibers stay airborne depends on factors such as fiber size and type, the amount of asbestos released, ventilation conditions, and disturbance method. Larger fibers settle faster, while thinner fibers can remain suspended for weeks. Amphibole asbestos remains airborne longer than chrysotile. Greater disturbance leads to higher initial fiber levels, and ventilation and disturbance methods also influence airborne times.
4. How long do different types of asbestos fibers stay airborne?
Heavier fibers above 5 microns settle within hours or minutes in calm or windy conditions, respectively. Smaller fibers below 5 microns can remain airborne for weeks with constant disturbance, and in extreme cases, they might never settle. Major fiber release can lead to elevated airborne presence for 48 hours or more, while low-impact disturbance results in dropped concentrations after a few hours.
5. What recommendations exist for minimizing asbestos exposure?
To minimize asbestos exposure, avoid disturbing asbestos-containing materials. If released, leave the area, isolate it if possible, and contact professionals. During renovations, have materials inspected for asbestos and hire accredited professionals for removal. Use protective equipment, improve ventilation, and follow safety regulations when dealing with older buildings.
6. How long is the latency period for asbestos-related health issues?
The latency period between asbestos exposure and the onset of diseases can be 20 years or more. Asbestos-related health issues may not arise until decades after initial exposure. The EPA warns that there is no safe level of asbestos exposure, and higher exposure increases the risk of disease.
7. What are the risks associated with inhaling asbestos fibers?
Inhaling asbestos fibers can lead to lung tissue scarring, shortness of breath, and mesothelioma, a rare cancer affecting the lung and abdominal linings. The severity of health risks increases with the amount of inhaled fibers. Early evaluation after exposure is advised even though fiber inhalation doesn’t always lead to disease.