Key Takeaways:
It’s that time of year again: Summer heat waves have arrived. Already this year, the United States has experienced a week-long heat dome that produced sweltering temperatures from the Midwest to the Atlantic. With hot weather comes increased fire risk and, in many areas, higher humidity levels.
What does this have to do with indoor air quality (IAQ)? During hot weather, many institutional and commercial facilities keep windows closed, go to minimum outside air settings and generally escape to the air-conditioned indoors. A great deal of research in the past several years points to the negative effects of poor IAQ, which often results from insufficient ventilation of particulate matter, chemical exposure and humidity.
The business impact of IAQ is hard to ignore:
When building occupants complain the indoor air is stuffy, they often are experiencing dry or burning eyes, fatigue, headaches and dizziness. Their sinuses act up, they have trouble concentrating, and there is a rise in absenteeism. In such cases, facility managers face an IAQ problem.
In addition to health concerns, productivity issues arise if people cannot perform their job functions. For organizations, the quality of the indoor air can have real financial impacts. That makes IAQ a critical facility management priority.
The U.S. Environmental Protection Agency (EPA) defines IAQ as the air quality within and around buildings and structures, especially as it relates to the health and comfort of building occupants. The American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) gets more technical, defining IAQ as the types and concentrations of airborne contaminants found in buildings, including pollutants from indoor and outdoor sources that can affect health, comfort, well-being, learning outcomes and work performance.
ASHRAE Standard 62.1 goes still further, defining acceptable IAQ as air in which there are no known contaminants at harmful concentrations, as determined by cognizant authorities, and with which at least 80 percent of occupants do not express dissatisfaction. What stands out in these definitions is a focus on the health and well-being of people, even when they are not overtly aware of what is affecting them.
Many sources can pollute indoor air. Contaminants can come from outdoor pollution, cleaning products, furniture, finishes, building materials, occupant activities and even an HVAC systems. They often include:
To ensure healthy IAQ, maintenance and engineering managers need to pay attention to four key elements:
Ventilation. This is the basis of effective IAQ management because it dilutes and removes indoor pollutants through continuously introducing outdoor air and exhausting air. ASHRAE Standard 62.1 and building codes set the minimum ventilation requirements for HVAC systems based on occupant population, activity, space size and system configuration. The goal is for any system to have balanced, consistent ventilation that meets code requirements while supporting occupant wellness, energy efficiency and system performance.
Filtration. This component removes particulate and gaseous contaminants from outside air and recirculated air. Filters are rated by their minimum efficiency reporting value (MERV) rating, which indicates their ability to capture particles of different sizes. The higher the rating, the smaller the particulate matter they capture.
Filters originally were installed to protect mechanical equipment. As we have learned more about particulate matter and its effect on human health, the emphasis has shifted. The more recent focus is on fine inhalable particulates. Particulate matter (PM) that is 2.5 microns or smaller has many facilities installing MERV 13 filters or an equivalent filtration level. A MERV 13 filter can remove 85 percent of PM2.5.
Moisture control. It is essential to keep water intrusion and humidity in check. Water intrusion from leaks or system failures can contribute to the proliferation of mold growth, which can have terrible consequences for occupants. Mold prevention is fundamentally about moisture management. While mold spores are always present in the environment, they only grow when moisture is available.
Common sources of excess moisture in facilities include roof leaks, plumbing failures and condensation on cold surfaces. Mold can begin growing in 24-48 hours, so addressing water intrusion promptly is important. It is also much less expensive than a mold remediation project.
Humidity control is often overlooked in facilities. Relative humidity levels that are too high or too low can cause problems. High humidity can create favorable conditions for mold growth and make occupants feel uncomfortable. Low humidity can cause different problems such as dry skin, irritated eyes and respiratory discomfort, and it can increase the resuspension of particles in the air.
While many managers put controls in place for high humidity, not many control for low humidity, Increasingly, guidelines advise managers to maintain indoor relative humidity of 30-60 percent. That might require the use of humidifiers and dehumidifiers to achieve the desired range. While this level of control might not be feasible for every facility, managers still should monitor humidity levels regularly and address underlying causes, such as air leaks, water leaks, insufficient ventilation, poor maintenance and equipment malfunctions to maintain desired conditions.
Source control. Managers need to work to keep contaminant generation to a minimum. Emissions come from building materials, furniture, finishes, appliances and human activities. Controlling what is allowed in buildings can reduce pollution sources.
Monitoring and maintenance are essential in understanding and addressing indoor air quality. The most common metrics monitored are temperature, humidity and carbon dioxide. Depending on the systems present and the sophistication of the IAQ program, managers also might monitor carbon monoxide, particulate matter and VOCs.
Regular monitoring allows managers to identify trends, detect problems early and evaluate the effectiveness of remedies. IAQ sensors and building management systems can provide real-time data and alerts when conditions fall outside acceptable ranges. This information supports data-driven decision-making and helps prioritize maintenance needs and system adjustments.
Managers also cannot forget about the most prolific sensors of all — occupants. They also sense temperature, humidity, odors and other conditions that can point to brewing IAQ issues. They are an important element of any monitoring strategy.
When coupled with a strong communication plan, monitoring also supports operational transparency by providing evidence of conditions and improvements. Combining system sensors and occupant input, managers can use this data to anticipate issues and demonstrate a proactive response.
Effective IAQ management incorporates consistent preventive maintenance, identification of problems and prompt attention to addressing issues. Supported with a monitoring program, it should include regular inspections of HVAC systems, the building envelope and any other areas of potential risk to help identify emerging issues early. When facility systems work well, occupants are more comfortable, their health and well-being is maintained, and organizations are equipped to operate at their best.
Laurie Gilmer is president and chief operating officer of Facility Engineering Associates. She is a published author and instructor and past chair of IFMA’s global board of directors, and she serves on the leadership team of the National Alliance for High-Performance Building Operations. She is a past member of the National Visiting Committee of Building Efficiency for a Sustainable Tomorrow Center and the advisory committee of the Northwest Energy Efficiency Council’s Building Operator Certification program.
