Is Your HVAC System Spreading Thirdhand Smoke?

05/30/2018 | By Justin Feit

It always seems like there’s something jeopardizing your facility’s air quality. You may have taken efforts to root out Sick Building Syndrome, reduce VOCs and improve occupant comfort. However, another unanticipated IAQ problem might be flying under the radar. You might be employing good source control and providing ample ventilation, but that might not be enough. Thirdhand smoke could be lingering in your facility from years ago, and you may be unknowingly spreading it.

Thirdhand smoke could be lingering in your facility from years ago and you could be spreading it.
Thirdhand smoke could be lingering in your facility from years ago.
 

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You may say to yourself, “This isn’t relevant to me. Workplace smoking hasn’t been legal for years in my state.” While this is true in many workplaces, thirdhand smoke from years earlier might actually be contributing to IAQ issues in your facility.

One Drexel University study on thirdhand smoke suggests that your HVAC system could be spreading more of the toxic chemicals left behind from smoking. Your building’s occupants might still be exposed to these chemicals even if your company prohibits smoking.

Is thirdhand smoke harming your facility’s IAQ?

What Is Thirdhand Smoke?

Most people are familiar with the dangers of secondhand smoke. Thirdhand smoke doesn’t have the same notoriety, but it does have some health risks.

“Thirdhand smoke is residual nicotine and other chemicals left on indoor surfaces by tobacco smoke,” notes the Mayo Clinic. “People are exposed to these chemicals by touching contaminated surfaces or breathing in the off-gassing from these surfaces. This residue is thought to react with common indoor pollutants to create a toxic mix including cancer-causing compounds, posing a potential health hazard to nonsmokers.”

Indoor surfaces that attract thirdhand smoke include furniture, walls, carpets, dust and other surfaces. It can’t be entirely eliminated by airing out rooms, using fans and air conditioning, opening windows or confining smoke to certain areas, according to the Mayo Clinic.

The exact health issues that thirdhand smoke causes are still under study. In 2013, researchers at Lawrence Berkeley National Laboratory discovered that thirdhand smoke causes DNA damage. Moreover, a 2016 study in Public Health Report notes “exposure may contribute acutely and/or chronically to poorer health outcomes across many populations.” However, the writers stress that definitive thresholds for harm haven’t been established.

HVAC and Thirdhand Smoke

Like many other IAQ issues, your first instinct might be to improve your ventilation to get rid of thirdhand smoke. However, your HVAC system might be making the problem worse.

The Drexel University study suggests that the harmful chemicals in thirdhand smoke attach themselves to aerosols and can be reemitted into a building. Your HVAC system, often used to improve IAQ, might be to blame for spreading harmful thirdhand smoke to the rest of your building.

“HVAC systems recirculate and disperse air throughout the multiple rooms of the zone served by the system, meaning that what happens in one room affects all the other rooms in the zone,” explain the researchers. “For this reason, a room located near a smoking area with smoke penetration or a room occupied by a smoker can effectively expose the other occupants served by the same HVAC system to thirdhand smoke, even if they do not share space directly.”

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In one classroom that hadn’t allowed smoking for several years, the researchers found that 29% of the aerosol mass contained thirdhand smoke chemicals. This suggests the problem doesn’t go away over time.

As temperatures rise, this problem can become even worse, as varying amounts of water are brought into the building, mixed with recirculated air and conditioned, the researchers explain. “This process leads to significant uptake of water by aerosol particles. This continuous summertime presence of aerosol water allows thirdhand smoke chemicals to partition into the aerosol phase.”

Protection from Thirdhand Smoke

What can you do to protect your facility? Unfortunately, the lack of clear answers about how these chemicals behave still raises many questions. But if you can reduce the sources of thirdhand smoke, you might be able to limit its effects.

Try replacing carpet, furniture and other softer surfaces that can hold onto thirdhand smoke for long periods. This can also contribute to your IAQ source control strategy, as you can implement interior materials that have low VOC levels and contribute to healthy indoor air.

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An air filtration system could also be an appropriate response. However, you’ll want to consult with experts to make sure the system you purchase to purify your air can remove thirdhand smoke chemicals from the air.

Justin Feit justin.feit@buildings.com is associate editor for BUILDINGS.


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