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Indoor Air Quality

Information adapted in full from U.S. Environmental Protection Agency's IAQ Tools for Schools Action Kit, IAQ Backgrounder.


Indoor air quality (IAQ) is an important issue in correction facilities. It can directly affect the health and comfort of correctional officers and inmates. The United States Environmental Protection Agency (EPA) fact sheet An Office Buildings Occupants Guide to Indoor Air Quality to help worksites address many IAQ issues using practical and often low-cost measures. The HITEC II Study research team has modified the EPA fact sheet for use in corrections within this section.


This guide is based on the following principles:

  • Most IAQ problems can be prevented and resolved through simple, inexpensive measures.
  • The cost and effort needed to prevent most IAQ problems is significantly less than the cost and effort required to resolve problems after they develop.

Why Is Indoor Air Quality Important to Your Work?

Most people are aware that outdoor air pollution can impact their health, but indoor air pollution can also have significant, harmful effect. EPA studies of human exposure to air pollutants indicate that indoor levels of pollutants may be two to five times—and occasionally more than 100 times—higher than outdoor levels. The EPA and its Science Advisory Board consistently rank indoor air pollution among the top five environmental health risks to the public.

Failure to prevent or respond promptly to IAQ problems can:

  • Increase potential for long- and short-term health problems for staff and inmates.
  • Negatively impact staff attendance, comfort, and performance.
  • Accelerate deterioration and reduce efficiency of facilities and equipment.
  • Strain relationships among administration and staff.

Understanding Indoor Air Quality Problems and Solutions

To understand IAQ problems and solutions, it is important to know what factors affect IAQ. These include:

  • Sources of indoor air pollutants
  • Heating, ventilation, and air condition (HVAC) systems
  • Building occupants
  • Pollution pathways

Sources of Indoor Air Pollutions

Indoor air contaminants originate within the building or can be drawn in from outdoors. Air pollutants consist of numerous particulates, fibers, mists, bioaerosols, and gases. It is important to control air pollutant sources, or IAQ problems can arise—even if the HVAC system is properly operating.

A complicating factor is that indoor air pollutant concentration levels can vary by:

  • Time (for example, weekly, during floor stripping); and
  • Location (within a building or even within a single room).

HVAC System Design and Operation

Properly designed HVAC equipment in the workplace helps to:

  • Control temperature and humidity to provide thermal comfort.
  • Distribute adequate amount of outdoor air to meet ventilation needs of building occupants.
  • Isolate and remove odors and pollutants through pressure control, filtration and exhaust fans.

Not all HVAC systems accomplish all of these functions depending on building needs and system design.

The two most common HVAC designs are unit ventilators and central air handling systems. Both can perform the same HVAC functions, but a unit ventilator serves a single room while a central air-handling unit serves multiple rooms.

Building Occupants

The effect of IAQ problems on building occupants—including staff and inmates—are often non-specific symptoms rather than clearly-defined illnesses. Symptoms commonly attributed to IAQ problems include:

  • Headache, fatigue, and shortness of breath
  • Sinus congestion, cough, and sneezing
  • Eye, nose, throat, and skin irritation
  • Dizziness and nausea

These symptoms could be caused by air quality deficiencies, but may also be linked to other factors—poor lighting, stress, noise. Due to varying sensitivities among staff members, IAQ problems may affect a group of people or just one individual. In addition, IAQ problems may affect people in different ways. Individuals that may be particularly susceptible to effects of indoor air containments include people with:

  • Asthma, allergies, or chemical sensitivities
  • Respiratory diseases
  • Suppressed immune system (due to radiation, chemotherapy, or disease)
  • Contact lenses

Pollutant Pathways and Driving Forces

Airflow patterns in building are determined by the combined forces of mechanical ventilation systems, human activity, and natural effects. Air pressure differences created by these forces move airborne pollutants from areas of higher pressure to areas of lower pressure through any available opening in building walls, ceilings, floors, doors, windows, and HVAC systems. Even if the opening is small, air will move until the inside pressure is equal to the outside.

Typical Sources of Indoor Air Pollutants

Six Basic Control Strategies

There are six basic control methods that can lower concentrations of indoor air pollutants.

  1. Source Management: management of pollutant sources include:
    • Source Removal: Eliminating pollutant sources or not allowing them to enter the buildings. Examples include not placing garbage in rooms with HVAC equipment, and replacing moldy materials.
    • Source Substitution: Replacing pollutant sources. Examples include selecting less or non-toxic materials paints.
    • Source Encapsulation: Placing a barrier around the source so that it releases fewer pollutants into the indoor air. Examples include covering pressed wood cabinetry with sealed or laminated surfaces or using plastic sheets to contain contaminants when renovating.
  2. Local Exhaust: Removing point sources of indoor pollutants (through exhausting fume hoods and local exhaust fans to the outside) before they disperse. Examples include exhaust systems for restrooms and kitchens, storage rooms printing and duplicating rooms.
  3. Ventilation: Lowering pollutant concentration by using cleaner (outdoor) air to dilute polluted (indoor) air. Local building codes likely specify the quantity (and sometimes quality) of outdoor air that should be continuously supplied in your buildings, as do voluntary standards set by the American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHREA). Temporarily increasing ventilation coupled with proper use of the exhaust system while painting or applying pesticides, for example, can be useful in diluting the concentration of noxious fumes in the air.
  4. Exposure Control: Adjusting the time and location of pollutant exposure. An example of time control is scheduling floor stripping and waxing (with the ventilation system functioning) on a Friday. This allows products to off-gas over the weekend while most of the staff are at home over the weekend. Location control involves moving the pollutant source away from occupants or even relocating susceptible occupants.
  5. Air Cleaning: Filtering particles and gaseous contaminants as air passes through ventilation equipment. In most cases this type of system should be engineered on a case-by-case basis.
  6. Education: Teaching and training correctional officers and staff about IAQ issues. People in the buildings can reduce their exposure to many pollutants by understanding basic information about their environment and knowing how to prevent, remove, or control pollutants.