We spend about 90% of our time indoors, according to the Environmental Protection Agency (EPA), so indoor air quality (IAQ) and indoor environmental quality (IEQ) affect everyone. In addition to air quality, IEQ includes the lighting, thermal, and ergonomics conditions within a building that affect occupants. In some cases, indoor air quality can be worse than outdoors. Older adults, children, and people with conditions like asthma and heart disease are more vulnerable to poor IAQ.
Identify Contaminants and Pollutants
A key step to improving the health of all occupants within an indoor space is to know what to look for and how to reduce its effects.
Chemical pollution indoors can negatively impact air quality. Steps to maintain indoor air quality include minimizing the use of cleaners, pesticides, perfumes, and household and personal chemical products. Mild soap and water can clean many surfaces and are less toxic than other cleaning products. The use of a damp rag to dust and vacuum floors helps reduce asthma triggers, allergens, pests, and pollutants that can be carried in from foot traffic and open doors and windows.
Paints, coatings, adhesives, sealants, and furniture that emit volatile organic compounds (VOCs), as well as substances that vaporize at room temperature, are common sources of indoor air contaminants. Controlling the indoor pollutants at the sources is the first line of defense. Next comes the building’s ventilation system.
Ventilation is important to remove any chemicals or contaminants from the air. Opening windows and doors with good weather and outdoor air quality can circulate fresh air throughout the building. Exhaust fans should also be turned on when cooking in the kitchen and showering in the bathroom. Combustion appliances like heaters, stoves, and dryers can produce dangerous pollutants indoors like nitrogen dioxide and nitric oxide. Other sources of nitrogen dioxide are vented appliances with defective installations, welding, tobacco smoke, and kerosene heaters.
It’s important to control indoor moisture in humid climates to prevent mold by keeping humidity levels between 30-50%. Sometimes, a dehumidifier may be necessary to remove the excess moisture in the air.
Why Consider IAQ and IEQ for Buildings?
Building and maintaining buildings and systems that promote good IAQ and IEQ benefits the occupants’ lives, increases the resale value of the building, and reduces the liability for building owners, according to the U.S. Green Building Council. The USGBC argues the best solutions include numerous strategies that promote efficiency and conversation while meeting the occupants’ needs and supporting their wellbeing.
So, what strategies can building owners and managers employ to improve occupants’ comfort and control within the built environment? Many of these strategies are part of the design and construction process: use daylighting, install operable windows, allow occupants to adjust temperature, ventilation, and lighting, survey occupants, provide ergonomic furniture, and incorporate acoustic design.
When buildings undergo renovation or expansion, strategies should consider how to contain both indoor and outdoor contaminants. The Centers for Disease Control's website links to the National Institute for Occupational Safety and Health's IEQ guidelines. It offers considerations from scheduling work during low building occupancy, isolating work areas with physical barriers, and using HEPA filtration to remove particulates and prevent air movement through doorways. The HVAC system within the construction or renovation areas should also be disabled or isolated from the rest of the building to prevent damage or contamination. Supply and return air grilles should be blocked or sealed in the work areas. Filtration efficiency should be upgraded to the highest level in spaces that must remain occupied during construction, and construction materials and equipment should be kept in a storage location to reduce contaminants from entering occupied spaces.
Health Implications of Poor IAQ
People exposed to poor indoor air quality can experience a range of health effects that show up quickly after exposure: irritation of the eyes, nose, and throat, headaches, dizziness, and fatigue, according to the EPA. A person’s reaction time to indoor air pollutants depends on age and preexisting medical conditions.
Nitrogen dioxide is one of the many indoor air pollutants a building’s occupants can be exposed to inside. When people are exposed to nitrogen dioxide, it affects the mucosa of the eyes, nose, throat, and respiratory tract. High-dose exposure can cause pulmonary edema and diffuse lung injury, and continued exposure can contribute to the development of acute or chronic bronchitis. Lower levels of exposure can cause asthmatics to experience heightened bronchial reactivity and patients with chronic obstructive pulmonary disease to have decreased lung function. People in spaces with poor IAQ are also at a higher risk of respiratory infections, particularly children.
