In an age where indoor air quality (IAQ) is paramount, HVAC professionals operating and designing commercial buildings are the unsung heroes in the battle for clean air. However, navigating the nuances of what constitutes 'clean air' is far from straightforward and packed with misconceptions that could compromise the very air we breathe. We're set to dismantle three major myths surrounding IAQ, offering insights to professionals like you.
Myth 1: Outdoor Air is Clean Air
The Ventilation Rate Procedure (VRP) has long been the standard for maintaining indoor air quality. Its principle is simple – introduce enough outdoor, presumed ‘fresh air’, to dilute the human generated contaminants in a space. Carbon dioxide, the primary indoor air contaminant, negatively affects human performance as levels increase. Along the way, the outdoor air, particularly if free of pollutants, also dilutes other toxins like volatile organic compounds and human-generated particulate matter. This standard for ventilation, the go-to approach to IAQ, does not address filtration of ultrafine particles or pathogens that are difficult to move within the breathing zone of an indoor space. The system is built around the idea that more outdoor air means better IAQ.
Yet, the reality is much more complex. Increasing outdoor airflow is no guarantee of cleaner air, especially in urban environments where pollutants abound. In 2021, the Environmental Protection Agency (EPA) reported 666 days across 35 major cities where air quality was deemed unhealthy for sensitive groups or above. In Los Angeles alone, 27% of the days that year exceeded these limits. This is the same air being fed into buildings as “fresh”.
This misconception arises from a period when ventilation was considered the best tool for achieving indoor air quality. However, with advancements in technology, a layered strategy produces better results. Bringing in more outdoor air could exacerbate IAQ problems, particularly with the introduction of hazardous particulate matter without adequate controls like filtration and air cleaning. Ventilating with high levels of outdoor air also places a significant energy burden, especially in hot, humid, and cold climates, leading to higher costs and an increased carbon footprint. It is often the policy to close outdoor air louvers when temperatures reach extremes or if outdoor particles spike, like during a wildfire.
Considering these alarming statistics, it's clear that relying on outdoor air alone isn't the best approach. Conditioning air today demands strategic ventilation that factors in local outdoor air quality and is balanced with energy efficiency. Professionals must be adept at executing this delicate balance to ensure that the air entering commercial spaces is as clean as it can be, without compromising on sustainability or cost.
Myth 2: Filters Are Enough to Clean Indoor Air
Filters are lauded for their air-cleaning abilities, and rightfully so when it comes to capturing larger particles. However, their effectiveness is notably reduced for particles smaller than 1.0 micron in diameter, including a wide range of viruses, bacteria, and contaminants found in tire wear, smog, and wildfire smoke. This is due to a significant weakness highlighted by the MERV Curve. This curve demonstrates a counterintuitive drop in filtration efficiency for these smaller particles before it gradually improves. The fine and ultrafine particulates below 1 micron often evade these barriers and continue to circulate in breathing zones.
Given the EPA's recent decision to tighten the air quality standard for fine particles from 12 micrograms per cubic meter to 9, the rates of unhealthy air quality days are poised to climb even higher. The EPA stated that this adjustment in standards was made to “protect millions of Americans from harmful and costly health impacts, such as heart attacks and premature death”, reinforcing the imperative for innovative indoor air quality solutions.
There exists a misconception that higher MERV-rated filters bridge the gap and improve ultrafine filtration, but the truth is more nuanced. Specific focus should be paid to how well high-rated filters actually perform on these small particles. To achieve strong removal efficiency, these filters often carry heftier price tags for purchase and maintenance, but they also require greater system energy to operate.
Underestimating the limitations of filters can have substantial implications for IAQ. The quest for cleaner air necessitates calls for a multi-pronged approach, where filters are just one element in a comprehensive strategy. Pairing them with technologies that address these smaller particulates can create a robust defense line that effectively cleans indoor air, maintaining optimal HVAC efficiency over time.
Myth 3: Electric Air Cleaners Do More Harm Than Good
The rise of electric air cleaners has been met with skepticism, primarily concerning the production of ozone as a byproduct. While some technologies do indeed contribute to indoor ozone levels, innovative technology has evolved with safety and efficacy in mind. Needlepoint Bipolar Ionization (NPBI®), a soft ionization method, is a prime example of a safe, ozone-free alternative that effectively reduces airborne contaminants without adverse health implications.
Hard ionization, on the other hand, employs high-energy processes that generate harmful byproducts, including potentially damaging ozone. Examples of hard ionization include UVC, Dielectric Barrier Discharge, and Photocatalytic Oxidation. It is crucial for HVAC professionals to be discerning when evaluating electric air cleaners, ensuring they adopt methods that are compliant with industry efficacy and safety standards, such as those found in ASHRAE Standard 241.
Without seeking to understand the technology, efficacy, and safety of specific air cleaning solutions, professionals risk missing out on effective tools that could significantly enhance IAQ more efficiently and cost effectively than other methods. Instead, by staying informed and adopting the latest accredited air cleaning technologies, HVAC experts can lead the charge in delivering truly clean air to the commercial spaces they serve.
Raising the Bar for Indoor Air Quality
With the stage set and the myths debunked, the call to action is clear for HVAC professionals: it is time to reassess our understanding of indoor air quality and the methods we employ to clean the air. This reassessment begins with education and transparency. Seek training on current IAQ technologies and standards, offer clear communication on the options available to clients, and ensure that your practices align with the latest industry guidelines.
While staying up to date with new science and technology might seem daunting, the advantages of maintaining clean indoor air are significant. It not only promotes healthier environments but also does so at a lower cost. By shattering these misconceptions, we open the door to a new era where IAQ is not just a buzzword, but a standard that we can confidently achieve and consistently maintain.
To all HVAC professionals, our challenge is to continue pushing the boundaries and promote a deep understanding of what it takes to achieve true indoor air quality. In doing so, we elevate not just our industry, but the health and well-being of those who work, learn, and live within the walls of the structures we serve.
Now is not the time for complacency; it is the time for innovation and precision. It is the perfect time to recalibrate our standards, learn from the misconceptions highlighted, and pioneer a new, insightful chapter in the history of indoor air quality management.
