With Americans spending an average of 90% of their time indoors, indoor air pollution poses a major health risk. This is especially true for young children, older adults, and people who have heart or lung diseases — who, by the way, all tend to spend even more time indoors.
Fortunately, HVAC technology offers a number of ways to prevent air pollution and improve indoor air quality (IAQ).
What are some causes of indoor air pollution?
Dust and other fine particles from vehicle exhaust, boilers, construction and other outdoor activities can find their way indoors through windows, doors, and other openings. This so-called fine particulate matter can also get drawn indoors through a building’s HVAC system.
In addition, mold, pet hair, dander, and dust mites can build up over time — contributing to indoor air pollution that can make it hard for people with allergies or chronic illnesses to breathe.
A lack of proper ventilation also contributes to IAQ issues. It allows the buildup of hazardous pollutants including cigarette smoke and volatile organic compounds (VOCs), which are emitted from sources such as paint products, synthetic building materials, carpeting and furniture, personal care products, pesticides, cleaning solvents, air fresheners, and dry-cleaned clothing.
Then there are pathogens — viruses (including the coronavirus that causes COVID) and bacteria that can linger on surfaces and in the air, spreading contagious illnesses. These pathogens may be distributed throughout a building by the HVAC system or be recirculated through ductwork.
Additionally, some of the newer building features designed to increase energy efficiency — such as airtight construction and improved insulation — can actually increase all of this indoor air pollution by limiting the flow of fresh air into the building.
Clearly, with so many risks for indoor air pollution, it makes sense to use whatever tools you can to improve IAQ. The following are 7 ways that HVAC technology can help.
1. Combat indoor air pollution with air purification technology
UVC-emitting lights are useful for destroying contaminants on surfaces. This technology can kill many microbes. You can have UVC lights installed within your HVAC system to keep the equipment free of pathogens, and reduce the risk of spreading them throughout a building.
Today, UVC has been incorporated into many healthcare facilities as part of air disinfection systems. Its use is also growing in other high-traffic buildings where air quality and preventing the spread of illness is a concern, such as:
Typically, UVC can be used in a number of ways, often in combination with other ventilation, particulate filtration, and other air quality control methods.
- Cooling coil disinfecting involves installing UVC coil-irradiation and airstream disinfection systems in HVAC equipment to keep the evaporator coil, drain pan, and surfaces clean. This method helps to prevent mold and other contamination from being circulated via the HVAC system.
- Duct and upper-air systems can be installed in the upper part of rooms — such as waiting rooms, classrooms, cafeterias, locker rooms, and emergency rooms — to keep the air clean once it is already circulating. These systems direct UVC energy up and out, creating a pathogen-killing zone at ceiling level while preventing exposure in the lower portion of the room.
- Surface disinfecting utilizes portable UVC devices in settings such as hospitals. This method is often used to reduce occurrences of staph and other hospital-acquired infections.
- Ultraviolet light air purification systems combine a traditional filtering component with UV light, to both remove particulate matter from the air and kill microorganisms. The UV component destroys particles that conventional filtration cannot capture — namely, viruses and bacteria.
Oxidation and ionization technology
UVC lights kill contaminants on surfaces. Oxidation and ionization air purifiers can do more: they destroy particles in the air, not only within your HVAC system, but also cleaning the air throughout your space.
Air purifiers that use oxidation and ionization technology are commonly used in healthcare facilities and food processing plants, and can significantly increase indoor air quality in other commercial, residential, and public sector spaces.
There are a number of different types of technology, including photocatalytic oxidation (PCO) and bipolar or plasma ionization, that work in different ways to target and destroy airborne particles. They are very effective at removing viruses, bacteria, mold spores, VOCs, and even odors from the air, and doing so very quickly. In fact, the devices can reduce sneeze germs by 99% in the time a sneeze can reach three feet.
Many businesses are installing these devices to mitigate the spread of COVID.
Here’s how they work in simple terms. These devices produce friendly, natural oxidizers that get distributed throughout your space, not only within your HVAC system. The technology takes oxygen molecules from the air and converts them into charged atoms that then cluster around tiny particles, surrounding and deactivating harmful substances like airborne mold, bacteria, allergens, and viruses.
Get our guide to learn more about HVAC Strategies for COVID.
2. Prevent indoor air pollution with good ventilation design
A properly designed ventilation system reduces indoor air pollution by providing fresh air, controlling odors, and removing contaminants that can cause physical symptoms and illness. For instance, exhaust fans can help to remove fumes from manufacturing activities and the use of chemicals or other materials. They can also reduce the concentration of virus particles that may be present in the air.
Other times, ventilation can be improved by relocating intakes, moving ductwork, or adding some other HVAC technology. A great example is make up air units for restaurant kitchens.
Proper kitchen ventilation is essential to keeping the space clean and reducing the buildup of unpleasant odors that could kill business. Many restaurants think that installing a commercial exhaust hood is enough to address the problem.
However, the addition of a make up air unit provides the necessary balance between the air being exhausted through the vent hood and the replacement (make up) air that is needed to:
- Prevent back drafting
- Avoid big swings in restaurant temperature
- Eliminate negative air pressure
- Improve air quality
Usually installed on the roof or in a mechanical room, a make up air unit replaces the air that’s been pulled out by the kitchen’s exhaust hood. The make up unit pulls in fresh air from outside, heat or cools it to the indoor temperature, and supplies it to the kitchen.
3. Use VRF for humidity (and temperature) control
High relative humidity levels can increase the concentration of some indoor air pollutants. For example, high humidity makes the air and surfaces moist, increasing the chance for mold to grow. Low humidity is a problem, too, because viruses, including the virus that causes COVID, thrives in low humidity conditions. In fall and winter when the heat is running, humidity levels often plummet indoors.
As part of your indoor air quality testing, you can use a humidity gauge to see if the humidity in your building is at a healthy level — between 30% and 50%. To maintain a good, consistent humidity level and temperature, consider a Variable Refrigerant Flow (VRF) system, which is a zoned HVAC technology.
A VRF HVAC system detects the precise requirements of each zone in a building and sends the precise amount of heating/cooling required. As a result, each area of the space is consistently comfortable with well-controlled humidity and no hot or cold spots.
4. Consider increasing filtration
While standard air conditioner and furnace filters do not remove pathogens like UVC does, these everyday filters still play an important role. They protect your HVAC equipment from dust and debris, to keep it performing efficiently.
What if you want an HVAC filter to do more?
One option is high efficiency particulate air (HEPA) filters, which are designed to reduce indoor air pollution by trapping 99.97% of dust, pollen, and smoke particles. The filters are rated using the minimum efficiency reporting value (MERV) scale; the higher the number, the better the filter’s ability to block particles of different sizes. HEPA filters are rated between MERV 17 and MERV 20. Standard HVAC filters are rated MERV 8.
HEPA filters are recognized by the Occupational Safety & Health Administration (OSHA) and the EPA for their ability to remove airborne particles. In fact, some UV air purification systems use a heavy-duty HEPA filter to trap the largest particles, such as dust, and UV fields to capture microscopic particles, such as viruses.
However, because HEPA filters restrict airflow (which can hurt performance and strain the system), many HVAC systems require some retrofitting to accommodate HEPA.
Another option is to consider MERV 13 filters, which offer additional filtration with less airflow restriction and less strain on the system.
The first step in making this choice is to call in an HVAC professional to adapt your system as needed. Your HVAC company can recommend the best filter choice for your equipment and your needs.
5. Clean the ductwork to reduce indoor air pollution
Whatever fine debris is circulating in your building’s air can end up accumulating in the ductwork — and that can significantly impact IAQ. Whatever is in your ductwork can end up back in the air you breathe.
A simple inspection can tell you if dust, mold spores, pollen, pet dander, or other airborne materials are building up. Those contaminants can contribute to health issues, especially for people who have asthma, allergies, or other breathing problems.
Having trained and certified specialists clean clogged ducts not only improves air quality, but also helps to improve HVAC system efficiency and prevent breakdowns. Before having ducts cleaned, ensure that your provider’s services are in accordance with NADCA and NAIMA standards.
Unchecked, mold is more than an IAQ issue. It is a health issue, causing symptoms such as headaches, nausea, irritated nose and throat, itchy eyes, and asthma.
If your ductwork has been invaded by mold, it is crucial to call an HVAC professional for remediation ASAP. Professionals have the proper chemicals to thoroughly remove the mold, as well as the equipment required to protect themselves, your HVAC system, and your building from the mold and the cleaning process.
In addition, an HVAC professional will determine where and how the mold problem originated, and help you resolve the underlying issue so that mold does not recur.
7. Stay on top of air quality with routine HVAC maintenance
Since the air that you breathe indoors is circulated by your HVAC system, regular professional system inspections and tune-ups are essential to good IAQ.
Investing in routine HVAC maintenance, coupled with the occasional duct inspection and cleaning, not only helps you detect, prevent, and eliminate sources of indoor air pollution — it also helps to ensure that your HVAC system is performing properly, for consistent comfort, cost effectiveness, and reliability.