Enhancing health and wellness by improving indoor air quality

LEED Fellow Hafsa Burt describes the areas where green builders must make progress in IAQ.

As we seek to transform how buildings and communities are designed, built and operated to enable a healthier world, taking steps to improve air quality is essential. Recent reports show that in 2023, only seven countries met the World Health Organization's air quality guidelines for pollution, meaning 90% of the global population is regularly exposed to hazardous pollutants in the air they breathe. This exposure is responsible for nearly 7 million premature deaths worldwide annually, according to The Guardian newspaper.

Improving indoor air quality (IAQ) plays a core role in shifting global health and wellness in a positive direction. Humans have created almost 350,000 synthetic substances that have become staples of our built environments. Building and consumer products frequently contain harmful chemicals, such as volatile organic compounds (VOCs), which can contaminate indoor air and can lead to chronic health issues.

HVAC systems also contribute to the challenges that the green building community faces in the area of IAQ. Achieving HVAC efficiency requires building envelope upgrades to prevent unnecessary leakage, but if HVAC systems don't incorporate at least MERV13 filters and a good air exchange rate per ASHRAE 189.1, those updates result in poor IAQ.

Important steps for improving air quality

In my design work, I typically orient most ground-up projects in a way that uses site orientation to support health and wellness. This includes leveraging wind direction, the sun's path and other natural components.

Terra Glen, a major multifamily renovation in San Jose, California. Photo credit: Jason Foy.

Using natural wind direction, for example, helps bring a fresh flow of air through plenums and windows. Air is pushed into the ductwork using a plenum and circulated throughout the system before being expelled when necessary. This frequently used method contributes to improved air quality and reduced energy consumption.

Establishing a good air exchange rate is important to improving overall IAQ. Optimal air exchange counters off-gassing of harmful chemicals from finishes and fixtures.

In California, standards have required compliance with SCAQMD Rule 1113 for architectural coatings limiting exposure to VOCs have been in place since 1989. These are mandatory measures under California's Green Building Code, known as CALGreen, for projects in most jurisdictions where the construction cost is over $200,000. Architects must include these requirements in their contract documents and during construction, and general contractors must show compliance by including in the project manual the Material Safety Data Sheet for materials used.

Air exchange also supports the removal of indoor and outdoor pollution. Proper air exchange keeps pollutants like PM2.5-particulate matter with a diameter of 2.5 micrometers or smaller-from infiltrating indoor spaces. These tiny particles are small enough to enter the lungs and may carry pollutants such as dust, dirt or smoke.

Carbon monoxide (CO) also must be monitored through either on-site performance tests or continuous monitoring with suitable sensors. Monitoring and regulating CO levels within the building to maintain them at 900 ppm or below is an effective strategy. This approach is particularly fitting for buildings outfitted with continuous air quality monitoring systems.

CO2 monitors should be placed in high-traffic, densely populated regions, positioned between three and six feet above the floor within the breathing zone. Installing IAQ monitors within the building and consistently gathering IAQ data is becoming the norm. These monitors measure at least three crucial parameters, but air quality sensors equipped with Internet of Things (IoT) capabilities continually observe IAQ indicators like particulate matter, VOCs, CO2, humidity and temperature. This data is instantly transmitted to building management systems, enabling prompt modifications and interventions to uphold indoor environments conducive to health.

Case studies on enhancing air quality

hb+a Architects has developed comprehensive performance specifications for IAQ relevant to the finishes we implement in all our projects. The Coffee and Water Lab in San Jose, California, provides an example of how we approach projects with a focus on air quality.

During the construction of the Coffee and Water Lab, which took place during the COVID-19 pandemic, we collaborated closely with our mechanical consultant to ensure compliance with ASHRAE 62.1. We also installed HEPA filters with booster fans and electrostatic precipitators that can capture airborne particles to enhance air exchange rates. We have also been looking at ultraviolet germicidal irradiation systems that use UV-C light to deactivate airborne pathogens such as bacteria, viruses and mold spores, reducing the risk of airborne transmission of diseases.

Coffee and Water Lab, San Jose, California. Photo courtesy of hb+a Architects.

Given the high foot traffic and popularity of the retail space where the project was located, which is especially high on weekends, it was crucial to use products with low-VOC finishes and to conduct thorough air flushing before occupancy. Using low-emission building materials, paints and furnishings can reduce the release of indoor pollutants, and our outdoor air delivery was designed to meet ASHRAE 189.1 standards, with continuous monitoring provided to ensure appropriate air volume supply.

For our Box Factory residence in Jackson, California, we optimized the design to make use of the prevailing wind direction to improve air quality. We also incorporated ceiling fans and operable windows to promote increased ventilation throughout the day, specifically in our residential projects. Incorporating natural ventilation strategies, such as operable windows, skylights and building orientation design, can enhance indoor air circulation and reduce reliance on mechanical ventilation systems. Certain indoor plants have air-purifying properties and can help remove airborne toxins, enhance oxygen levels and improve overall IAQ.

The future of air quality design

Since 2009, when I started advocating for healthy buildings and attention to IAQ, the industry has made encouraging strides. These include more attention paid to product development, the adoption of health-focused codes and measures that require compliance with SCAQMD's Rule 1113. General awareness among industry leaders has also significantly improved in recent years.

Box Factory. Photo credit: Doug Birnbaum.

Advanced air purification technologies such as photocatalytic oxidation, activated carbon filtration and bipolar ionization can effectively neutralize and remove VOCs, odors and other harmful airborne contaminants. AI-driven, smart building management systems that analyze IAQ data, occupancy patterns and external environmental conditions to optimize HVAC operations, indoor air quality and occupant comfort automatically will also become the norm.

Still, the fight is far from over. We must continue to advocate for fresh air intake, operable windows and more restrictive requirements for finishes and fixtures, if we are to create spaces where people can live healthy lives.

RESET certification highlights the significance of continuous monitoring of air quality. For commercial interiors, RESET Air's high-performance criteria are significantly stricter, especially regarding PM2.5 and CO2. PM2.5 levels must remain below 12 micrograms per cubic meter, while CO2 levels should not surpass 600 ppm. The IAQ Assessment requirement in LEED, which involves air testing, is highly reliable, as it assesses contaminant levels during occupancy.

The WELL Building Standard is another certification that emphasizes the continuous monitoring of indoor air quality. It sets rigorous performance criteria for pollutants such as PM2.5 and CO2 to ensure healthy indoor environments.

Construction sites are a frontier where much work is needed. Construction workers' exposure to toxic materials during the building process should become a mainstream topic of discussion, so that their overall well-being and productivity can be supported through proper safety measures and protocols that minimize the risk of exposure to harmful substances.

The multitude of factors that must be considered in a building project makes optimizing IAQ a complex challenge, but it is one that all architects, designers and builders must embrace to grow the health of the people who occupy our buildings and, ultimately, the health of our planet.

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