Indoor Air Quality in Commercial and Institutional Buildings

Indoor Air Quality in Commercial and Institutional Buildings

Introduction

Indoor Air Quality also referred to as IAQ, is a major concern to, workers, tenants, building managers, schools, and businesses because it can impact the productivity, well-being, comfort, and health of the building occupants. OSHA recognizes that because of poor IAQ, it can be hazardous to the health of workers and that it’ is in the best interest of everyone that employers, managers, and building owners take a proactive approach to address IAQ concerns.

Background

IAQ has been identified by the 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 YESAir IAQ Monitor.jpgAmericans spend approximately 90 percent of their time indoors. On average, office workers spend approximately 40 hours a week in office buildings.

These workers also drink, eat, study, and, in specific work settings, sleep in environments that are enclosed where make-up air (i.e., fresh air added to re-circulated air) could 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 activities conducted within the building, occupant densities, air handling systems have been maintained, and the occupants’ satisfaction with their environment. IAQ problems can arise from a single source or any combination of factors. Inadequate IAQ could start with  the failure of the building enclosure or poor building design or envelope (foundation, facade, roof, 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 and operated heating, ventilating and air-conditioning and ventilating (HVAC) systems, overcrowding, radon, moisture incursion and dampness, presence of outside air pollutants outside, moisture incursion, radon, overcrowding, and the presence of internally generated contaminant presences like thesuch as use of cleaning and disinfecting and cleaning supplies and especially aerosol products, off-gassing from materials in the building, and use of mechanical equipment. Improper temperature and relative humidity conditions can also present bring up problems, especially and also concerning comfort.

Lots of IAQ complaints are related to flaws in the design of buildings and insufficient routine preventive maintenance of the HVAC systems, plumbing, and building enclosures (envelopes).

To resolve many IAQ problems, a preventive maintenance program should be established on the basis of the system’s recommended  schedule of maintenance outlined by the engineer or architect,  HVAC professional, or a manufacturer. Consistent preventive maintenance ensures not only  that systems are properly operating, but also can lead to increased worker productivity, improved operating efficiency, and cost savings. Among others, Tthe U.S. Green Building Council (USGBC) has established that issues with IAQ  can be practically and readily addressed when building systems are upgraded for energy efficiency.

Health Effects

Symptoms related to poor Indoor Air Quality are varied depending on the type of contaminant. They could easily be mistaken for symptoms of other illnesses like influenza, colds, stress, and allergies. Usually, the clue is that people start to 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).

Health or symptom surveys, such as the one included in Appendix D, have been used to help ascertain the existence of IAQ problems.

Failure of operators and building owners to respond fast and efficiently to IAQ problems can lead to several negative health conditions. Health conditions from indoor air pollutants could be experienced shortly after exposure or, probably, years later. Symptoms may include irritation of the throat, nose, and eyes, ; fatigue and muscle pain, rashes, dizziness, and headaches. Diseases linked to poor IAQ include hypersensitivity pneumonitis and asthma.

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 Indoor Air Quality. Age and preexisting medical conditions such as asthma and allergies may also influence the severity of the effects. Long -term effects due to indoor air pollutants may include respiratory diseases, heart disease, and cancer, all of which can be severely debilitating or fatal.

Research has linked building dampness with significant health effects. Numerous species of bacteria and fungi, in specific filamentous fungi (mold), can contribute greatly to indoor air pollution. Whenever enough moisture’s present within workplaces, these microbes can start growing and affecting the health of workers in many ways. Workers may start to develop asthma, allergies, or respiratory symptoms. Sinusitis, nasal congestion, sneezing, sinus congestion, shortness of breath, wheezing, cough, and asthma have all been associated with indoor dampness in numerous studies. Asthma is both caused by and worsened by dampness in buildings.

The most effective means to prevent or minimize adverse health effects is to determine the sources of persistent dampness in the workplace and eliminate them. More details on preventing mold-related problems can be found in the OSHA publication titled: “Preventing Mold-Related Problems in the Indoor Workplace”. Other environmental factors such as poor lighting, stress, noise, and thermal discomfort may cause or contribute to these health effects.

Sources of Indoor Air Pollutants

The relative significance of any single source is depending on the emission of a given pollutant, how dangerous those emissions are, occupant proximitycloseness to the emission source, and the ability of the ventilation system (i.e., general or local) to remove the contaminant. In some cases, factors such as the age and maintenance history of the source are significant.

Sources of indoor air pollution may include:

Building Site or Location:

The location of a building can have implications for indoor pollutants.
Highways or busy thorough fares may be sources of particulates and other pollutants in nearby buildings. Buildings sited on land where there was prior industrial use or where there is a high water table may result in the leaching of water or chemical pollutants into the building.

Building Design:

Design and construction flaws may contribute to indoor air pollution. Poor window and door openings, facades, roofs, and foundations may allow water or pollutant intrusion.

Outside air intakes set nearby sources where pollutants are drawn back into the building (e.g., idling vehicles, products of combustion, waste containers, etc.) or where building exhaust reenters into the building can be a constant source of pollutants.

Buildings with multiple tenants may need an evaluation to ensure emissions from one tenant do not adversely affect another tenant.

Building Systems Design and Maintenance:

When the HVAC system is not functioning properly for any reason, the building is often placed under negative pressure. In cases like this, there may be outdoor pollutants infiltrations like parking garage contaminants, humid air, vehicle exhaust, particulates, etc.
Also, when spaces are renovated or redesigned, the HVAC system might not be updated to accommodate the changes. For example, one floor of a building that housed computer services may be renovated for offices. The HVAC system would need to be modified for office employee occupancy (i.e., modifying temperature, relative humidity, and air flow). Indoor Air Quality

Renovation Activities:

When painting and other renovations are being conducted, dust or other by-products of the construction materials are sources of pollutants that may circulate through a building. Isolation by barriers and increased ventilation to dilute and remove the contaminants are recommended.

Local Exhaust Ventilation:

Copy rooms, locker rooms, soiled laundry rooms, trash rooms, toilet rooms, beauty and nail salons, parking garages, maintenance shops, laboratories, kitchens, and other specialized areas may be a source of pollutants when they’re lacking enough local exhaust ventilation.

Building Materials:

Acoustical material that’s Sprayed-on or disturbing thermal insulation, or the presence of  damp or wet structural surfaces (e.g., ceilings, walls) or non-structural surfaces (e.g., shades, carpets), may contribute to indoor air pollution.

Building Furnishings:

Furniture or cabinetry made of particular pressed-wood products could release pollutants into the indoor air.

Building Maintenance:

Workers in areas in which pesticides, cleaning products, or applying personal-care products  could be exposed to pollutants. Letting cleaned carpets to dry with no active ventilation could result in microbial growth.

Occupant Activities:

Occupants of the building could be the source of air pollutants indoors; such pollutants are inclusive of colognes or perfumes.

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, condensation, inadequate humidity control, water spills, or water intrusion through leaks in the building envelope or flooding.

Chemical

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

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 the outside. Particles can also be produced by activities that occur in buildings such as operating equipment, copying, printing, drywall or sanding wood, and construction.

Prevention and Control of IAQ Problems

IAQ Management Approach

Ideally, an employer should use a systematic approach when addressing air quality in the workplace.

The components of a systematic approach for addressing Indoor Air Quality are the same as those for an overall safety and health program approach and include program audit, hazard identification and control, employee involvement, training, and management commitment. 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.

It is recommended that building owners/managers develop and implement an IAQ management plan to address and, prevent, especially resolve IAQ problems in certain buildings. The EPA’s report, IAQ Tools for Office Buildings provides a set of flexible and specific activities that can be useful to building owners/managers for developing such a plan. A key feature of the plan is the selection of an IAQ Coordinator. The role and functions of an IAQ Coordinator are described in Section 3 of the EPA’s report, IAQ Tools for Schools Action Kit (24).

Other critical features of the plan include establishing necessary IAQ policies, evaluating the current status of IAQ in buildings via periodic inspections, maintaining appropriate checklists and logs, performing necessary upgrades and repairs, and implementing follow-up assessments or other needed actions. An employer who leases space must know about the program of the building management ’and methods for resolving or mitigating problems with indoor air quality.

It is especially important for employers to know who to contact in buildings where there is mixed- use and pollutants are emanating from other sources in the building. Employers should negotiate leases that specify Indoor Air Quality performance criteria. For example, a lease should specify that the space is ventilated with outdoor air while occupied and at a rate described in ASHRAE 62.1 Ventilation for Acceptable Indoor Air Quality. An important management strategy is to foster a team approach for problem-solving and consensus building. The IAQ Team should include, but not necessarily be limited to, contract service providers, building healthcare staff, custodians, facility operators, administrative staff, building occupants, and other interested parties.

Identification and Assessment

The used methods in an IAQ investigation could include evaluating the HVAC system performance, identifying pollutant sources, observing work practices and production processes, measuring employee exposures and contamination levels, providing physical examinations or medical testing,  reviewing records of medical tests and conducting employee interviews, illnesses and injuries, and job histories. The Appendices provide resources and checklists that occupants, managers, and building owners can use correct IAQ problems, document walkthrough inspections, and investigate IAQ complaints.

To prevent IAQ problems effectively and efficiently, building managers should know and understand the history of the building (construction, uses, maintenance, etc.). If possible, owners and managers should maintain blueprints and construction documents, including information about any renovations of the building.

Some important practices include:

• Inspect and assess the building envelope, including the roof, walls, and foundation, and promptly respond to identified problems. Routinely check the building for water leaks, seals around windows and doors, and any  moist parts or visible damp of the building. Clean and dry any damp or wet building materials and furnishings within 24 to 48 hours after detection to prevent the growth of mold.
• Ensure and validate that the building is maintained under a slight positive pressure (i.e., air comes out of the building when exterior doors are opened).
• Check whether the temperature and humidity are maintained in a recommended comfort range (temperature: 68 to 78 degrees and relative humidity: 30% to 60%).
• Ensure that routine maintenance of the HVAC system is being performed, including the performance of the system bringing outdoor air into the building. (1).
• Monitor carbon dioxide (CO2) levels. The carbon dioxide levels can be used as a rough indicator of excessive population density (e.g., overcrowding), and the effectiveness of ventilation.
• Ensure that good housekeeping practices are being applied.
• Ensure that routine preventive maintenance and upkeep of buildings  are being performed. A preventive maintenance program provides the care to all building systems and components that keep them operating at peak performance according to the manufacturer’s specifications, and also allows for early detection of problems.
• Ensure that scheduled renovations are isolated from the general dilution ventilation system  of the building when occupants are in the building.

Control Methods

There are three basic control methods for lowering concentrations of indoor air pollutants:

1. Source management

Source management includes removal, substitution, and enclosure of sources. It is the most effective control method when it can be applied practically.

1. For instance, the U.S. Consumer Product Safety Commission is recommending getting  carpets that’ re low-volatile organic compound (VOC) emitters installed, and would encourage consumers to inquire installers or retailers about the voluntary “green label” program of the carpet industry for the latest carpets. Based on the carpet industry, the white and green logo shown on carpet samples of carpets letsinforms the consumer know that certain manufacturer’s’ product has  undergone testing by an independent laboratory and has met the criteria for very low emissions. The label, however, is not a guarantee that the carpet will not cause health problems. One more example’s that the employer can arrange temporary barriers or set the space below negative pressure relative to adjoining areas that are adjoining to ensure that the pollutants are contained during construction activities.

Engineering Controls

a. Local exhaust

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.

b. General dilution ventilation

General dilution ventilation systems, when properly designed, operated, and maintained, will control normal amounts of air pollutants. A well functioning and designed HVAC system controls temperature as well and relative humidity levels to give thermal comfort, distributes plenty 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. Appendix

C contains an HVAC System Maintenance Checklist that can be used to assist in routine maintenance of the HVAC system. For particular situations, like carpet cleaning and painting,  increasing ventilation temporarily can help weaken the concentration of vapors in the air.

Air Cleaning

Air cleaning mainly involves removing particles from the air as the air passes via the HVAC equipment. Most HVAC system filtration is provided to keep dirt off of coil surfaces to promote heat transfer efficiency.

Most of the smudging seen around air supply diffusers in a ceiling is due to entrainment (trapping) of particles of dirt in the space that gathers there as a result of poor housekeeping.

Administrative Controls

a. Work Schedule

Managers can greatly minimize the amount of pollutant exposure within their buildings through scheduling. For example:

1.Reduce or eliminate the amount of time a worker’s exposed to a pollutant (i.e., scheduling  cleaning work and maintenance to be done when other occupants of the building aren’t present).

2. Reduce the amount of chemicals being used by or near workers (i.e., limit the amount of chemicals being used by the worker during maintenance or cleaning activities).

3. Control the location of chemical use (i.e., 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).

b. Education

Education of building occupants regarding Indoor Air Quality is important. If 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 employer and/or take action to reduce their personal exposure.

c. Housekeeping

Housekeeping practices should include preventing dirt from entering the environment ( for example, using walk-off mat systems), getting dirt removed once it’s in the building, storing food properly, disposing of garbage, and choosing cleaning methods and products that reduce the pollutants introduc into the building.

Some indoor air problems can be resolved when good practices are put in place to control contaminants and also building personnel follows good approaches to housekeeping . Other problems may be difficult to resolve, however, and may require outside assistance. A building owner or manager may first want to consult local, state, or federal government agencies (e.g., education, health, environmental protection, or agriculture agencies) for assistance or direction in solving IAQ problems. These governmental agencies may be able to help an employer identify the types of experts who could best assist them.

Examples of experts include:

• Structural engineers – address issues with structural elements such as corrosion problems in a building’s foundation;
• Architects – responsible for designing the building envelope and can mitigate water intrusion problems by creting vapor barriers;
• Mechanical engineers – balance and test HVAC systems and may be able to assess and recommend repairs/replacement of HVAC systems and local exhaust ventilation systems; and• Industrial hygienists – assess general IAQ parameters such as air changes in a building, carbon dioxide levels, carbon monoxide levels, and other indoor pollutants, and also evaluate contaminant levels.There may be private firms or consultants in your area with experience in IAQ work. Such firms may be found in general resources such as a telephone directory (e.g., under “Engineers,” “Environmental and Ecological Services,” “Laboratories-Testing,” or “Industrial Hygiene Consultants”), on the Internet, or by asking building owners/managers for referrals.Some professionals who work with Indoor Air Quality issues must meet licensing and certification requirements to practice in their disciplines. A consultant should base any testing recommendations or protocol on a thorough visual inspection, walk-around, and interviews with building occupants.

Source by: OSHA