Indoor Air Quality

Introduction

Indoor air quality (IAQ) is a major concern to employers and employees because it can impact the health, comfort, well-being, and productivity of the building occupants. OSHA recognizes that poor IAQ can be hazardous to workers’ health and that it is in the best interest of everyone that the University takes a proactive approach to address IAQ concerns.

This program provides guidance on IAQ issues through practical recommendations that will help prevent or minimize IAQ problems in institutional buildings, and help resolve such problems quickly if they do arise. This program helps the University keep their buildings free of pollutants or conditions that lead to poor IAQ.

Background

IAQ has been identified by the Environmental Protection Agency (EPA) as one of the top five most urgent environmental risks to public health. The Centers for Disease Control and Prevention (CDC) estimates that the majority of Americans spend approximately 90 percent of their time indoors. On average, office workers spend approximately 40 hours a week in office buildings. These workers also study, eat, drink, and, in certain work settings, sleep in enclosed environments where make-up air (e.g., fresh air added to recirculated air) may be compromised. For this reason, some experts believe that more people may suffer from the effects of indoor air pollution than from outdoor air pollution.

Each building has its own set of circumstances. Air quality may be determined by the site of the building, its original design, renovations, whether air handling systems have been maintained, occupant densities, activities conducted within the building, and the occupants’ satisfaction with their environment. IAQ problems can arise from a single source or any combination of factors. Inadequate IAQ may begin with poor building design or failure of the building enclosure or envelope (roof, facade, foundation, etc.). Other issues may be associated with the location of the building and mixed uses of the building. Many common IAQ problems are associated with improperly operated and maintained heating, ventilating and air-conditioning (HVAC) systems, overcrowding, radon, moisture incursion and dampness, presence of outside air pollutants, and the presence of internally generated contaminants such as use of cleaning and disinfecting supplies and aerosol products, off-gassing from materials in the building, and use of mechanical equipment. Improper temperature and relative humidity conditions can also present problems, especially concerning comfort. Many IAQ complaints are associated with flaws in building design and by inadequate routine preventive maintenance of building enclosures (envelopes), plumbing, and HVAC systems. To avoid many IAQ problems, the University has a preventive maintenance program based on the system’s recommended maintenance schedule, the equipment’s manufacturer, and our in-house HVAC department. Regular preventive maintenance not only ensures that systems are operating properly, but also can result in cost savings and improved operating efficiency.

Benefits of Mitigation of IAQ Problems

Good IAQ in buildings is an important component of a healthy indoor environment. It contributes to a favorable and productive environment for building occupants, giving them a sense of comfort, health, and well-being. Significant increases in employee productivity have also been demonstrated when the air quality was adequate.

Health Effects

Symptoms related to poor IAQ are varied depending on the type of contaminant. They can easily be mistaken for symptoms of other illnesses such as allergies, stress, colds, and influenza. The usual clue is that people feel ill while inside the building, and the symptoms go away shortly after leaving the building, or when away from the building for a period of time (such as on weekends or a vacation).

Symptoms may include irritation of the eyes, nose, and throat; headaches; dizziness; rashes; and muscle pain and fatigue. The specific pollutant, the concentration of exposure, and the frequency and duration of exposure are all important factors in the type and severity of health effects resulting from poor IAQ.

Common Pollutant Categories

Although there are numerous indoor air pollutants that can be spread through a building, they typically fall into three basic categories: biological, chemical, and particle.

Biological

Excessive concentrations of bacteria, viruses, fungi, dust mites, animal dander, and pollen may result from inadequate maintenance and housekeeping, water spills, inadequate humidity control,
condensation, or water intrusion through leaks in the building envelope or flooding.

Chemical

Sources of chemical pollutants (gases and vapors) include emissions from products used in the building (e.g., office equipment; furniture, wall and floor coverings; pesticides; and cleaning and
consumer products), accidental spills of chemicals, products used during construction activities such as adhesives and paints, and gases such as carbon monoxide, formaldehyde, and nitrogen dioxide, which are products of combustion.

Particle (Non-biological)

Particles are solid or liquid, non-biological, substances that are light enough to be suspended in the air. Dust, dirt, or other substances may be drawn into the building from outside. Particles can also be produced by activities that occur in buildings such as construction, sanding wood or drywall, printing, copying, and operating equipment.

Prevention and Control of IAQ Problems

IAQ Management

Ideally, an employer should use a systematic approach when addressing air quality in the workplace. The components of a systematic approach for addressing IAQ are the same as those for an overall safety and health program approach, and include management commitment, training, employee involvement, hazard identification and control, and program audit. Management needs to be receptive to potential concerns and complaints, and to train workers on how to identify and report air quality concerns. If employees express concerns, prompt and effective assessment and corrective action is the responsibility of management.

The University has established this program to address, prevent, and resolve IAQ problems in their buildings. A key part of the program is the selection of an IAQ Coordinator. Other critical
features include establishing the necessary IAQ protocols, assessing the current status of IAQ in buildings through periodic inspections, maintaining appropriate logs and checklists, performing
necessary repairs and upgrades, and implementing follow-up assessments or other needed actions. This program applies to lease spaces as well. The University follows the criteria set forth by ASHRAE 62.1 Ventilation for Acceptable Indoor Air Quality. An important strategy is to foster a collaborative approach for problem solving and consensus with facility operations and building occupants.

Identification and Assessment

Methods used in an IAQ investigation include identifying pollutant sources, evaluating the HVAC system performance, observing production processes and work practices, measuring contamination
levels and employee exposures, providing medical testing or physical examinations, conducting employee interviews, and reviewing records of medical tests, job histories, and injuries and illnesses. Detailed checklists are use to investigate IAQ complaints, document walkthrough inspections, and correct IAQ problems. Campus Operations maintains blueprints and construction documents, including information about any renovations of the building.

Important practices include:

  • Inspecting and assessing the building envelope, including the roof, walls, and foundation, and promptly respond to identified problems. Routinely checking the building for water leaks, seals around doors and windows, and any visible damp or moist parts of the building. Cleaning and drying any damp or wet building materials and furnishings within 24 to 48 hours after detection to prevent the growth of mold.
  • Ensuring and verifying that the building is maintained under a slight positive pressure (e.g., air comes out of the building when exterior doors are opened).
  • Checking whether the temperature and humidity are maintained in a recommended comfort range (temperature: 68 to 78 degrees and relative humidity: 30% to 60%).
  • Ensuring that routine maintenance of the HVAC system is being performed, including the performance of the system bringing outdoor air into the building.
  • Monitoring carbon dioxide (CO2) levels. The carbon dioxide levels can be used as a rough indicator of the effectiveness of ventilation, and excessive population density (e.g., overcrowding).
  • Ensuring that good housekeeping practices are being applied.
  • Ensuring that routine preventive maintenance and upkeep of buildings is being performed. The preventive maintenance program provides the care to all building systems and components that
    keeps them operating at peak performance according to manufacturer’s specifications, and also allows for early detection of problems.
  • Ensuring that scheduled renovations are isolated from the building’s general dilution ventilation system when occupants are in the building.

Control Methods

There are three basic control methods used by the University for lowering concentrations of indoor air pollutants:

Source management

Source management includes removal, substitution, and enclosure of sources and is the most effective control method the University uses whenever it can be applied practically. For example, installing carpets that are low-volatile organic compound (VOC) emitters or using low-volatile paints and adhesives. Another example is installing temporary barriers or place the space under negative pressure relative to adjoining areas to contain the pollutants during construction or renovation activities.

Engineering controls

  • Local exhaust, such as a canopy hood, is very effective in removing point sources of pollutants before they can be dispersed into the building’s indoor air.
  • General dilution ventilation systems, when properly installed, operated, and maintained, will control normal amounts of air pollutants. A well-designed and functioning HVAC system
    controls temperature and relative humidity levels to provide thermal comfort, distributes adequate amounts of outdoor air to meet the ventilation needs of building occupants, and also dilutes and removes odors and other contaminants. Testing and rebalancing of HVAC systems are essential when partitions are moved in buildings. Under certain situations, such as painting and carpet cleaning, temporarily increasing ventilation can be implemented to help dilute the concentration of vapors in the air.

Air cleaning and filter changes

Air cleaning primarily involves the removal of particles from the air as the air passes through the HVAC equipment. The HVAC system filtration is provided to keep dirt off of coil surfaces to promote heat transfer efficiency. Dust and dirt observed around air supply diffusers are a result from entrainment (trapping) of dirt particles in the space that accumulate usually due to inadequate housekeeping.

Administrative controls

Work Schedule

Through scheduling, managers can significantly reduce the amount of pollutant exposure in their buildings.

For instance:

  • Eliminate or reduce the amount of time a worker is exposed to a pollutant (i.e., scheduling maintenance or cleaning work to be accomplished when other building occupants are not present).
  • Reduce the amount of chemicals being used by or near workers (e.g., limit the amount of chemicals being used by the worker during maintenance or cleaning activities).
  • Control the location of chemical use (e.g., perform maintenance work on moveable equipment in a maintenance shop as opposed to the general area, or locate the equipment (e.g., printers, copiers) in a separate room.

Education

  • Educating building occupants regarding IAQ issues. Occupants are provided with information about the sources and effects of pollutants under their control, and about the proper operation of the ventilation system, they can alert their supervisor or manager so they can take action to reduce employee exposures.

Housekeeping

  • Housekeeping practices include preventing dirt from entering the environment (using for example, walk-off mat systems), removing dirt once it is in the building, disposing of garbage, storing food properly, and using cleaning products and methods that minimize the introduction of pollutants into the building.