Improving Air Quality Through Advanced Filtration Techniques

The Current State of Air Quality

Recent data from the American Lung Association's 2024 State of the Air Report highlight the air quality challenges faced by Americans. The report provides insight into two of the most prevalent and concerning air pollutants: fine particles and ozone. It relies on air quality data collected at official monitoring sites nationwide by a range of government entities, including federal, state, local, and Tribal governments. Through this data, the report calculates values to understand the severity of the air pollution problem. It then assigns grades for daily and long-term measures of particle pollution and daily measures of ozone. These values are used to rank cities, metropolitan areas, and counties based on their air quality. The report uses the most recent publicly available validated data from 2020 to 2022.

An annual "Pass/Fail" grade for particle pollution (PM2.5) was determined based on the 2024 National Ambient Air Quality Standard for annual PM2.5, set at 9 μg/m3. Counties or metropolitan areas with PM2.5 concentrations below this threshold received a passing grade. Additionally, they were ranked according to their pollutant concentration levels. California stood out, with 15 of the top 25 most polluted counties and 6 of the top 10 most polluted cities. Notably, the San Francisco, Los Angeles, and Sacramento metro areas ranked 5th, 6th, and 7th, respectively.?

From urban centers like Denver and San Francisco to rural areas like Siskiyou and Uintah, both high ozone levels and particulate pollution remain concerns that significantly impact public health. For instance, Kern County, CA exhibits notably high ozone levels, with a weighted average grade of 87.5, alongside a particle pollution weighted average grade of 61.8, giving it an F in both categories and ranking it among the highest in the state. Note that 3.3 is the failing weighted average grade threshold. Even in Utah, known for its diverse natural beauty, urban areas such as Salt Lake County face elevated ozone levels of 24 with particle pollution at 9.8. The study found that 4 out of 10 people live in places with unhealthy levels of air pollution. These pollutants can exacerbate respiratory conditions, cardiovascular disease, and other health issues.??

The Role of Air Filtration

Air filtration in HVAC systems is essential for protecting both equipment and occupants from outdoor pollutants. Using filters with higher MERV ratings plays a critical role in improving indoor air quality. Industry experts recommend deploying higher efficiency passive filters, molecular filters, and air purification systems to significantly reduce the presence of harmful particulates and smog indoors. Understanding the role of air filtration is crucial to protect occupants from potential health impacts associated with poor indoor air quality.?

Passive Filters

A standard filtration method is a passive filter. These filters operate by trapping particles within a tightly woven media as air flows through, like a sieve. Their capture efficiency is gauged by the Minimum Efficiency Reporting Value (MERV) rating. However, the commonly used MERV 8 filter falls short in capturing particles smaller than PM2.5, being only 20% effective in this range. Opting for a MERV 13 filter or higher is advisable, as they can capture at least 85% of PM2.5 particles and 50% of smaller particles, offering a superior solution.?

HEPA filters, which stand for High-Efficiency Particulate Air filters, are capable of trapping at least 99.97% of particles as small as 0.3 microns. These filters are highly effective in removing fine particulate matter smaller than PM2.5 that is prevalent in pollutants like smoke, dust, and pollen. Installing high efficiency filters in HVAC systems or using standalone HEPA filter air purifiers can be particularly beneficial in counties with high particle pollution levels, such as Tulare and Fresno counties in California.??

Statically Charged Filters

The capture efficiency of filters can be enhanced by applying static charges to the filter media. This charge enhances the MERV rating by not only trapping particulate matter as air passes through the fiber openings but also attracting it to the media. It is worth noting on charged filters that unless the electrical charge is continuously applied, the fibers will eventually lose that charge and the capture efficiency will decrease over time. There are premium filtration technologies that use an actively polarized media with remarkably high MERV capture efficiencies and lower static pressures than similarly rated passive filters. Implementing this technology requires coordination to comply with the power and space requirements.?

Electronic Air Cleaners

An alternative approach is to utilize specialized devices capable of applying charges directly to particles rather than the media. This process causes the charged particles to attract to each other, forming larger aggregates that are easier to trap within the filter media. Other electronic air cleaners generate reactive molecules that bind to harmful gases, transforming them into harmless gases like carbon dioxide, nitrogen, and water vapor before ever making it to the occupied space. Experts recommend deploying these technologies judiciously, considering their efficacy and safety.?

Molecular Filters

Combining particle filtration technology with a molecular filter can help reduce particulate and gas-phase pollutants, either as two separate filters in series or as a combination unit. These filters use activated carbon or specific chemical blends to adsorb or chemisorb gases as they pass through the media. These are excellent solutions to remove exhaust fumes, odors, and smog from the air entering a building through the HVAC system.??

Upgrading HVAC Systems

Beyond improving filtration, upgrading HVAC systems to increase air exchange rates and incorporate air quality sensors can further enhance indoor air quality. Modern systems can adjust ventilation rates based on real-time air quality data, ensuring that indoor environments remain safe even during periods of high outdoor pollution. This approach is especially crucial in areas with fluctuating pollution levels.??

When considering upgrades to the filtration system, it is essential to understand the capabilities of the HVAC system. While higher MERV efficiencies in passive filters offer tighter filtration, they can also increase static pressures, brake horsepower, and energy consumption. Balancing indoor air quality with energy efficiency presents a challenge for building engineers and designers. Selecting the appropriate air purification technology is crucial for maintaining or enhancing indoor air quality. This is especially critical when increasing outdoor air rates becomes impractical, overly energy-intensive, or potentially harmful—such as during wildfire smoke events, where increased outdoor air intake can introduce harmful pollutants to the occupied space.

Practical Recommendations

For urban centers with high pollution levels, implementing stringent air filtration protocols in buildings can help shield vulnerable populations, including children and the elderly, from the adverse effects of air pollution. In rural and less populated areas, where industrial and agricultural activities might contribute to poorer air quality, localized solutions such as installing air purifiers in homes and community centers can be effective.?

Local governments and health departments can also promote public awareness about the benefits of advanced air filtration and provide guidelines for residents and businesses on how to improve indoor air quality. Subsidies or incentives for upgrading to efficient HVAC systems could accelerate the adoption of these technologies in both residential and commercial buildings.?

Conclusion

The data from the American Lung Association underscores the urgent need for improved air quality across various U.S. regions. By embracing advanced air filtration technologies and upgrading HVAC systems, communities can significantly enhance indoor air environments, thereby reducing the health impacts of outdoor air pollutants. These efforts require collaboration among governmental bodies, health organizations, and the public to ensure a cleaner, healthier future for all residents in these diverse and dynamic regions.?

For solutions to meet your filtration needs in the Northern California, Nevada, Colorado, Wyoming, Utah, Hawaii, and Pacific areas, visit norman-wright.com.

Authors: Jose Bocanegra, IAQ Product Manager, and Jenny Abney Sivie, LEED AP - CIO / Director of Marketing, Norman S. Wright Mechanical Equipment.

Jose Bocanegra is the Indoor Air Quality (IAQ) Product Manager at Norman S. Wright. With nearly 10 years of experience in the HVAC industry, his background allows him to apply a practical science-driven approach to promoting building occupant health.

Jenny Sivie is CIO / CMO with Norman S. Wright and well known in the business as both a product and marketing expert. You can find her regular technical video series, covering all aspects of commercial HVAC along with much other information on our YouTube channel NSW HVAC Academy.

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