Understanding Indoor Air Pollution

Indoor Air Pollution: A Serious Threat

• Indoor air pollution can pose a greater threat to human health than outdoor air pollution.
• This is primarily due to the amount of time spent indoors and the presence of many indoor pollution sources.
• Indoor Air Quality (IAQ) relates to how well indoor air satisfies the basic requirements for human occupancy.
• These requirements are:
  • Thermal acceptability
  • Maintenance of normal concentrations of respiratory gases
  • Dilution and removal of contaminants to levels below health or odor discomfort thresholds
• Absence of these requirements can lead to bad indoor air quality and pose a threat to health.

Some Indoor Air Pollutants, Their Sources, and Health Effects

• Tobacco Smoke:
  • Source: Cigarettes.
  • Possible threats: Lung cancer, respiratory problems, heart diseases.
• Asbestos:
  • Source: Pipe insulation, vinyl ceiling and floor tiles.
  • Possible threats: Lung diseases and lung cancer.
• Nitrogen Oxides:
  • Source: Unvented gas stoves, kerosene heaters, and wood stoves.
  • Possible threats: Lung irritation and headaches.
• Carbon Monoxide:
  • Source: Unvented stoves, kerosene heaters, and wood stoves.
  • Possible threats: Headache, irregular heartbeats, and death.
• Chloroform:
  • Source: chlorine-treated water in showerheads.
  • Possible threat: cancer.
• Formaldehyde:
  • Source: Furniture stuffing
  • Possible threats: Eye, throat, skin and lung irritation, nausea, and dizziness.
• Styrene:
  • Source: Carpets and plastic products.
  • Possible threat: Kidney and liver damage.
• Radon:
  • Source: Radioactive soil and rocks surrounding the building.
  • Possible threat: Lung cancer.
• Methylene Chloride:
  • Source: Paint and Thinner.
  • Possible threat: Nerve disorders and diabetes.
• Particulates:
  • Source: pets, dust, and cooking smoke particles.
  • Possible threats: Lung irritation, asthma, runny nose, and lung irritation.
• The United States Environmental Protection Agency ( US EPA) has determined that the most dangerous air pollutants are:
  • Tobacco smoke
  • Formaldehyde
  • Radioactive radon
  • Very small fine and ultrafine particle

Indoor Air Pollutants & Health

• IAQ may negatively affect people in three general areas: comfort, acute health effects, and chronic health effects.
• Health effects from indoor air pollutants can be experienced immediately or years after exposure.
• Immediate effects:
  • Usually appear after a single exposure and can cause irritations, headaches, dizziness, and fatigue.
  • These are usually short term and treatable.
• Later effects:
  • Can result in respiratory diseases, heart diseases, and cancer from repeated exposure.
  • These can be un treatable and fatal.
• Major health effects related to indoor air pollution include:
  • Acute lower respiratory infections (ALRI)
    • There is consistent evidence that exposure to smoke increases the risk of acute lower respiratory infections (ALRI) in childhood, particularly pneumonia.
  • Chronic obstructive pulmonary disease (COPD)
    • Indoor air pollution is considered a risk factor for chronic bronchitis (CB) and chronic obstructive pulmonary disease (COPD), which is a progressive and incompletely reversible airflow obstruction.
  • Lung cancer
    • Smoke from coal contains substantial amounts of carcinogens (chemical substances known to increase the risk of cancer).
    • There is evidence that women exposed to smoke from coal fires in the home have an elevated risk of lung cancer.
• Other health outcomes include low birth weight, prenatal mortality, asthma, otitis media, nasopharyngeal cancer, laryngeal cancer, cataract (blindness), and cardiovascular disease.
• According to a 2018 WHO report, around 3 billion people still use solid fuels (wood, crop wastes, charcoal, and coal) and kerosene in open fires and inefficient stoves, which contribute to household air pollution.
• Around 3.8 million people die prematurely each year due to illnesses caused by household air pollution from the inefficient use of solid fuels and kerosene for cooking.
  • 27% of these deaths are due to pneumonia, 18% from stroke, 27% from heart disease, 20% from chronic obstructive pulmonary disease (COPD), and 8% from lung cancer.

Building Related Illness & Sick Building Syndrome

• A 1984 World Health Organization Committee Report indicated that up to 30% of new or remodeled buildings worldwide may have "Indoor Air Quality" (IAQ) problems.
• Indoor air problems result from poor building design and occupant activities inside the building.
• IAQ issues are reflected in the dissatisfaction of building occupants with the indoor environment and associated complaints.
• "Building Related Illness" (BRI):
  • Diagnosable illnesses can be directly linked to airborne building contaminants through symptoms.
• "Sick Building Syndrome" (SBS):
  • Describes situations where building occupants experience health and comfort symptoms linked to time spent in a building, but no specific illness or cause is identified.
  • The complaints can be localized to a room or spread throughout the building.
• Common symptoms include eye, nose, or throat irritation, irritability, headaches, dry skin, nausea, fatigue, dizziness, nasal congestion, difficulty in concentration, and difficulty in breathing.
• Sick Building Syndrome can be considered an early stage of Building Related Illness.
• Indicators of SBS include: Building occupants complain of symptoms associated with acute discomfort (headache, eye, nose, and throat irritation), the cause of the symptom is unknown and most of the complaints report relief soon after leaving the building
• Indicators of BRI include: Building occupants complain of symptoms such as cough, chest tightness, fever, chill, symptoms can be clinically defined and have clearly identified causes complaints may require prolonged recovery time after leaving the building

Sick Building Syndrome: The Investigation

• An investigation of the building is needed when determining if SBS is BRI

• The disciplines that should be involved in investigations

  • Health professionals, who understand the physiology & psychology of humans and study and identify the diseases.
  • Engineers, who understand the mechanical systems and identify deviations from good design, operation, & maintenance.
  • Environmentalists & Industrial Hygienists who identify environmental pollutants & their characteristics

• The goal of a building investigation is to identify and solve indoor air quality complaints to prevent recurrence and avoid further problems.

• An investigator should follow these steps:

  • Collect information
  • Build a hypothesis
  • Test the hypothesis

• Steps the investigator should follow, in order, to collect information, form a hypothesis and test the hypothesis are:

  • Preliminary assessment:
    • Data gathering (mainly by interviews/questionnaires).
    • Getting historical information about the building.
    • Asking questions regarding; for the kinds of symptoms people have been experiencing and over what period of time.
  • Walk through inspection- conducted by trained in-house staff / the diagnostic team walk-through evaluation is needed to:
    • obtain any additional background information not obtained from the preliminary information
    • gain a visual appreciation for the design, engineering & architectural aspects, maintenance... of the building.
    • a critical inspection of HVAC (heat, ventilation & air conditioning) systems to characterize the building.
  • Simple diagnostics
    • More extensive analytical procedures are conducted by the diagnostic team.
    • Possible medical assessment (pleural mesothelioma) may be conducted.
    • On-site environmental monitoring may be used.
    • The most common instruments used are:
      • Psychrometers for measuring temperature and humidity
      • Detector tubes for carbon dioxide
      • Tracer gas for determining air movement.
      • PCM (Phase contrast microscopy) for asbestos
  • Complex Diagnostics
    • Broad in-depth testing, qualitative studies of factors in combination, and medical examination
  • Monitoring and Recurrence Prevention
    • Preventative measures are required to avoid future occurrences

• Some major causes of SBS

  • Inadequate Ventilation:
    • Inadequate ventilation can occur when the mechanical or natural ventilation system fails to effectively distribute air inside the building.
    • In the early to mid-1900s, building ventilation standards called for approximately 15 cubic feet per minute (cfm) of outside air for each building occupant.
    • In 1973, the standard changed to only 5 cfm.
    • These reduced air ventilation rates were inadequate to maintain health and comfort, so it changed back to 15 cfm.
    • ASHRAE recommends that homes receive 0.35 air changes per hour but not less than 15 cubic feet of air per minute (cfm) per person. Sometimes 60 is needed depending on the activity in the place
  • Chemical Contaminants from Indoor Sources:
    • Most indoor air pollution comes from sources inside the building.
    • Adhesives, pesticides, and cleaning agents may emit volatile organic compounds- VOCs. Tobacco smoke emits high levels of VOCs.
    • VOCs cause chronic and acute health effects and some carcinogenic.
  • Chemical Contaminants from Outdoor Sources:
    • The outdoor air that enters a building may be a source of indoor air pollution through openings or poorly located intake vents, such as those polluted by : car exhaust and industries.
  • Biological Contaminants:
    • Examples: bacteria, mold, and viruses. Can breed in stagnant water accumulating in ducts and humidifiers, where water has collected in ceiling tiles.
    • Insects or bird droppings.

• Solutions to the Sick Building Syndrome:

  • Source Control
    • Sources containing asbestos can be sealed or enclosed. Storage of paints and adhesives should be in well ventilated places. New building material should be allowed time to off-gas pollutants before occupancy.
    • Source control is a cost efficient approach which help avoid increasing energy costs as opposed to improving ventilation
  • Increasing Ventilation Rates. :increasing outdoor air
  • Air Cleaning: Air filter
  • Education and communication