March 11, 2007

Indoor Air Pollution


Indoor air pollution is a major public health problem that threatens virtually all workers in New York State's school buildings; from teachers and custodians to nurses and office staff. Contaminated indoor air occurs when toxic substances combine with inadequate building ventilation causing health problems such as eye irritation, nose and throat irritation, sinus discomfort, headaches, sneezing and coughing, respiratory infections, and fatigue.

Because of varying sensitivity among people, one individual may react to a particular indoor air quality (IAQ) problem while surrounding occupants do not display ill effects. In other cases, complaints may be widespread. In addition to different degrees of reaction, an indoor air pollutant or problem can trigger different types of reactions in different people. Groups that may be particularly susceptible to effects of indoor air contaminants include, but are not limited to:

  • allergic or asthmatic individuals, or people with sensitivity to chemicals
  • people with respiratory disease
  • people whose immune systems are suppressed due to radiation,
  • chemotherapy, or disease
  • contact lens wearers

Most people are aware that outdoor air pollution can damage their health. However, they may not know that indoor air pollution can also be harmful. Environmental Protection Agency (EPA) studies of human exposure to air pollutants indicate that indoor air levels of many pollutants may be 2-5 times, and, on occasion, more than 100 times, higher than outdoor levels. These levels of indoor air pollutants are of particular concern because it is estimated that most people spend as much as 90% of their time indoors. Over the past several decades, our exposure to indoor air pollutants is believed to have increased due to a variety of factors. These include the construction of more tightly sealed buildings, reduced ventilation rates to save energy, the use of synthetic building materials and furnishings, and the use of chemically formulated personal care products, pesticides, and household cleaners. In recent years, comparative risk studies performed by the EPA and its Science Advisory Board (SAB) have consistently ranked indoor air pollution among the top five environmental risks to public health.


In school buildings, poor air quality can be traced to many sources including office equipment, classroom supplies and construction materials. In addition, schools are often designed or renovated without attention to ventilation, resulting in sealed windows, blocked vents, and a general lack of fresh air.

Office Equipment

Electrical equipment such as photocopiers may give off ozone, which irritates the eyes and the respiratory tract, causes headaches, and has been shown to cause adverse genetic effects. Ink toner in photocopying machines may contain toxic substances. Mimeograph and ditto machines use many dangerous substances including methanol, a solvent that can dry the skin, irritate the eyes, nose and throat, and cause dizziness or even blindness. Many common office supplies are also dangerous, releasing vapors and dusts that can cause a variety of skin and respiratory problems. These include glue, rubber cement, inks, carbon paper, typewriter ribbon, carbonless copy paper and solvent-based correction fluid.

Renovations and New Furnishings

A variety of solvents are used in roofing, painting and renovation work, and they can cause skin dryness, respiratory irritation and, with greater exposure, dizziness or nausea. New York State Department of Education regulations mandate the health and safety of building occupants during construction for all capital construction projects. If the building continues in operation during the construction, the work site must be completely isolated from the occupied portion, and precautions taken to assure that operations or hazards in the work site will not affect building occupants. Districts must ensure that their architects or engineers adequately address the above concerns in contracts and that these concerns are followed during construction. Formaldehyde, one of the most common pollutants in school buildings, is found in office furniture, new carpets, particleboard, plywood, and many other products. As it deteriorates, formaldehyde gives off vapors that can cause sensitization and irritation of the eyes and respiratory system even at low levels.

Art, Science and Vocational Classes

Hazardous materials can be found throughout the art, science and vocational classrooms – and some substances are extremely toxic. These include heavy metals in pigments, clay dust, formaldehyde, solvents, photography chemicals, wood dust and metal fumes. Exposure can cause health effects ranging from mild eye irritation to cancer.

Custodial and Maintenance Work

Chemicals such as ammonia, solvents, paint strippers, chlorine and bromine, and strong cleaners are widely used by custodians and maintenance workers in the course of their jobs. Many of these substances can lead to respiratory irritation, chronic lung disease, and eye irritation. Making matters worse, these chemicals can easily spread through the ventilation system to entire sections of a school building, putting everyone in the area at risk. Particularly dangerous groups of chemicals are pesticides and herbicides. These highly toxic substances can remain in the air long after being sprayed. They can irritate the skin, eyes and lungs. Herbicide residues sprayed outdoors may migrate into building air systems or through open windows.


Moisture in the ventilation system can breed fungi (molds) and bacteria, which can spread throughout the school causing respiratory irritation, skin problems, development or worsening or allergies, fatigue, headaches and asthma. Molds can be a potential source of severe health problems. The American Lung Association states that the number of individuals with asthma has increased an astounding 59% since 1970. Asthma often results from overexposure to molds. Dampness can also build up in carpets or within walls, causing similar problems. Water leaks in pipes or roofs can result in moisture-damaged materials such as ceiling tiles, dry wall, or carpeting. These damaged materials then produce mold spores, even after the leak has been stopped.


Diesel exhaust, containing carbon monoxide and other toxic substances, can enter schools through improperly located air-intake vents from loading docks or from idling buses and vans. Carbon monoxide causes headaches, dizziness and nausea, and can be traced to malfunctioning combustion equipment, such as boilers. The environment around a school may be another source of indoor air pollution if toxic vapors or gases from neighboring industrial plants or waste dumps enter the ventilation system.

Second-hand Smoke

The Environmental Protection Agency (EPA) has determined that second-hand tobacco smoke can cause cancer. In early 1993, the EPA released a report, Respiratory Health Effects of Passive Smoking: Lung Cancer and Other Disorders , that evaluated the respiratory health effects from breathing second-hand smoke [also called environmental tobacco smoke (ETS)]. The EPA report classified second-hand smoke as a Group A carcinogen, a designation that means that there is sufficient evidence that the substance causes cancer in humans. The Group A designation has been used by EPA for only 15 other pollutants, including asbestos, radon, and benzene. Only second-hand smoke has actually been shown in studies to cause cancer at typical environmental levels. The EPA estimates that approximately 3,000 American nonsmokers die each year from lung cancer caused by second-hand smoke. Second-hand smoke is a risk factor for the development of asthma in children and worsens the condition of up to one million asthmatic children. New York State requires that indoor smoking areas, if any, be separate and ventilated so that second-hand smoke does not reenter the ventilation system.

Outdoor Sources

Ground-level ozone (smog), carbon monoxide, and particles such as soot, dust or smoke that are found in the environment are regulated by the Clean Air Act of the Environmental Protection Agency (EPA). Toxic Substances Release Inventories as they relate to nearby factories are available to the community upon request. Examples of polluted outdoor air include pollen, dust, fungal spores; industrial emissions; and vehicle emissions. Nearby sources to be investigated include loading docks, odors from dumpsters, and unsanitary debris or building exhausts near outdoor air intakes. Underground sources include radon, pesticides, sewage odors, contaminants from previous uses of the site (such as landfills), and leakage from underground storage tanks.

Building Equipment

Heating, Ventilating, Air-Conditioning Equipment (HVAC) should be checked for the following:

  • Microbial growth in air conditioner drip pans, ductwork, coils, and humidifiers, improperly maintained cooling towers;
  • System air flow rates;
  • Maintenance of HVAC system
  • Treated boiler water leaks
  • Improper venting of combustion products; and
  • Dust or debris in ductwork

Non-HVAC equipment should also be checked for PCBs in electrical equipment, emissions from office equipment (volatile organic compounds, ozone) and emissions from shops, labs, and cleaning processes.


Check for:

  • Water-damaged materials;
  • Condensation on walls or windows;
  • Roof, plumbing, refrigerant leaks
  • Dry traps that allow the passage of sewer gas;
  • Materials containing volatile organic compounds, inorganic compounds, or damaged asbestos; and
  • Materials that produce particles (dust)


Look for:

  • Emissions from new furnishings and floorings, carpeting and particle board;
  • Microbial growth on or in soiled or water-damaged furnishings.

Other Indoor Components:

  • Science laboratories fumes and vapors
  • Vocational arts areas/blueprint machines
  • Copy/print areas/spirit duplicators
  • Food prep areas
  • Cleaning materials and processes
  • Emissions from trash
  • Pesticides
  • Odors and volatile organic compounds from paint, chalk, adhesives
  • Motors and other mechanical systems
  • Occupants with communicable diseases
  • Dry-erase markers and similar pens
  • Insects and other pests
  • Personal care products
  • Emissions from stored supplies; e.g., carbonless copy paper


In a typical office ventilation system, the blower moves the air, the ducts deliver it to the room, and the vents supply or remove it. Outside air is introduced in varying amounts to mix with old air. To eliminate indoor air pollution, there must be a good source of fresh air and sufficient air movement. Unfortunately, ventilation in both new and old buildings is frequently inadequate. Many older buildings do not have a mechanical ventilation system. While some fresh air may enter through doors, windows, and cracks (a process called infiltration), it is often not enough. And during winter months or when energy conservation measures are implemented, fresh air may be cut off entirely.

Sealed Buildings

New buildings with sealed windows present their own air quality problems, relying solely on mechanical ventilation systems to bring outdoor air into the building and move it to all areas. When the system fails because of contamination, blockage, or other problems, air quality may suffer dramatically. To save energy, some buildings use ventilation systems which recirculate air that has already been heated or cooled. The air is passed through a filter and sent back through the building. The percentage of fresh air can be as low as 5 to 10%, and germs and chemical contaminants multiply in the recirculated air, significantly raising the risk of both irritation and infection. To remove fumes and dust from a specific operation, a local exhaust system is used. Examples: A dust control system in a wood shop; a ventilation hood in the chemistry lab. But these systems can create other problems if they are not the right size, are not hooked up properly, don't have enough air movement, or are not well maintained.



  • Increase air supply. Clean and maintain the ventilation system and open and unblock all sources of fresh air.
  • Eliminate sources of contamination, like carpeting. Substitute less dangerous chemicals, such as water-based paints for more toxic oil paints.
  • Clean and dry damp areas where fungi can grow.
  • Isolate and provide local exhaust for machines that release toxic fumes.
  • Make sure hazardous work is done only on the weekends or vacations, and inform the union before it begins.
  • Ensure that people who work with hazardous chemicals are protected with adequate ventilation or protective equipment, such as respirators.
  • Provide information about all chemicals in use as required by the New York State Right to Know law and PESH. Compare Material Safety Data Sheets (MSDSs) to choose less hazardous products.
  • Maintain temperature within the comfort zone of 65 to 75 degrees Fahrenheit, and humidity within barometric pressure of 20-40%.
  • Ensure that all local exhaust systems pull polluted vapors away from people's breathing area, and that local systems do not compete with the primary ventilation system, otherwise, pollutants re-enter ventilation intakes.
  • Bring in a ventilation engineer or Certified Industrial Hygienist (CIH) to verify that air movement is sufficient and to recommend remedies for any problem areas. The investigation can determine if you meet the American Society of Heating, Refrigerating and Air Conditioning Engineers (ASHRAE) indoor air quality standards, These recommend 20 cubic feet per minute (cfm) of fresh air per person in offices and 15 cfm in classrooms. Carry out any changes and improvements recommended by the ventilation engineer. ( See Table 1)
  • Institute Integrated Pest Management.


  • Conduct a health survey of the members, looking for problems typical of indoor air pollution and check to see if symptoms are linked to the workplace. Your NYSUT Labor Relations Specialist can give you sample surveys.
  • Investigate your building's ventilation system. Find out what type of system, if any, is used. To check the effectiveness of a ventilation system, hold tissue paper near the vents to see if they work. There should be both a supply and exhaust vent in each room. Also check for problems with local exhaust systems.
  • Develop recommendations to improve air quality.
  • Write contact language that will protect your rights to clean air. Your NYSUT Labor Relations Specialist can suggest sample language, using the ASHRAE standards as a guide.
  • If you have a well-documented problem and you are not making any progress with the school district, consider calling your county Health Department. If you feel the situation is very serious, you may also want to file a request for a Health Hazard evaluation conducted by the National Institute for Occupational Safety and Health (NIOSH). According to law, employers must provide safe, healthy workplaces that are free of hazards, including indoor air pollution. (Always work with your union representative when filing a complaint. But don't stop working! Complaints to a governmental agency or NIOSH are no substitute for consistent union action.)
  • Follow legislative activity – and get involved. While there is no comprehensive federal or New York State regulation on indoor air pollution, legislation has been proposed and several other states have enacted indoor air pollution laws.

Develop a safety and health committee to work to correct indoor air problems. The committee can conduct a health survey, investigate the ventilation systems, determine priorities, and push management to correct problems.


American Society of Heating, Refrigerating and Air-conditioning Engineers Ventilation Standards

Table 1: Selected ASHRAE Ventilation Recommendations

Type of Area Occupancy (people per 1000 sq feet) CFM/person

Instructional Areas

Classrooms 050 15
Laboratories 030 20
Music rooms 050 15
Training shops 030 20
Staff Areas
Conference rooms 050 20
Offices 070 20
Smoking lounges 007 60
Bus garage: 1.5 cubic feet per minute (CFM) per square foot of floor area. Distribution among people must consider worker location and concentration of running engines; stands where engines are run must incorporate systems for positive engine exhaust withdrawal. Contaminant sensors may be used to control ventilation.

Assembly Rooms

Auditoriums 150 15
Libraries 020 20
Spectator areas 150 15
Playing floor 030 20
Food and Beverage Service
Cafeteria 100 20
Kitchen 020 15

Additional airflow may be needed to provide make-up air for hood exhaust(s). The sum of the outdoor air and transfer air of acceptable quantity from adjacent spaces shall be sufficient to provide an exhaust rate of not less than 1.5 CFM/square foot.


Nurse's offices (patient areas) 010 25
Corridors: 0.1 CFM/square foot
Locker rooms: 0.5 CFM/square foot
Restroom: 50 CFM/urinal or water closet

Source: ASHRAE Standard 62-1989, Ventilation for Acceptable Air Quality .

From: "IAQ Backgrounder", Tools for Schools, Environmental Protection Agency .