Pub Health 4310 Health Hazards in Industry

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Pub Health 4310Health Hazards in Industry

• David Wallace
• Lecture 8
• Indoor Air Quality and MCS

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Indoor Air Quality and MCS

• Objectives
• Students should be familiar with
• Health effects associated with indoor air quality
• Issues of Multiple Chemical Sensitivity (MCS)
• Environmental factors of indoor air
• Ventilation system problems
• Pollutants encountered in buildings -
  recognition, evaluation and control

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Indoor Air Quality and MCS

• Introduction (based on the White Book, chapter
  20)
• The indoor environment is not always safe
• Buildings can be a source of contaminants
• Contaminants can accumulate
• IAQ problems stem from energy conservation
  efforts in 1960s and 1970s
• Exposure standards dont usually apply
• Comfort and health can be affected by contaminant
  levels below published exposure standards
• Definition of acceptable indoor air quality
• No known harmful contaminants, acceptable to 80
  of people (ASHRAE)
• Comfort" issues, not health, drive IAQ

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Indoor Air Quality and MCS

• Health Effects related to Indoor Air Quality
• Overview
• Indoor contaminants usually impact respiratory
  tract, mucous membranes
• Commonly used terms can confusing and presumptive
• Tight Building Syndrome
• Recommended terms are more accurate
• Building Related Disease, BRD
• Objective clinical findings of infection,
  allergic or toxin-induced disease
• Sick Building Syndrome, SBS
• Comfort and health-related symptoms, without
  objective clinical signs

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Indoor Air Quality and MCS

• Health Effects related to Indoor Air Quality
• Sources of agents
• Occupants
• Contagious disease, allergens
• Building components
• VOC (volatile organic compounds), particles,
  fibers
• Contamination
• Microbiological agents, allergens, pesticides
• Outdoor air

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Indoor Air Quality and MCS

• Building Related Disease (BRD)
• Hypersensitivity Diseases
• IgE-mediated (asthma, allergic rhinitis, hay
  fever)
• Hypersensitivity pneumonitis
• All require sensitization of the immune system
• Infections
• Contagious diseases (influenza, common cold,
  tuberculosis)
• Spread through indoor air, crowded environments
• Legionnaires diseases
• Spread from environmental reservoir

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Indoor Air Quality and MCS

• Building Related Disease (BRD)
• Toxicoses
• Toxins
• Dose-response effects
• Sources
• Products of combustion
• CO, NO2
• Materials used in the environment
• VOCs

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Indoor Air Quality and MCS

• Nonspecific Building Related Symptoms (BRS)
• Sick Building Syndrome, SBS
• Subjective symptoms
• Mucous membrane irritation, sinus congestion, eye
  irritation, cough, headaches, fatigue, dry skin,
  dizziness, nausea
• Attack rate gt 20
• Attributed to VOCs, low RH, endotoxin, house
  dust, inadequate fresh air

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Indoor Air Quality and MCS

• Nonspecific Building Related Symptoms (BRS)
• Psychosomatic Illness
• Caused by suggestion or stress
• Symptoms can mimic SBS
• Space-time occurrence not associated with
  ventilation system
• Person-to-person transmission
• Mass psychogenic illness, MPI, has been
  implicated in high profile cases
• Often with environmental trigger or
• Also termed mass hysteria

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• LONDON, March 23, 2006 - Sick building syndrome
  might be more aptly named "lousy job syndrome," a
  study here suggested.
• Syndrome symptoms correlated only weakly with the
  environmental properties of office buildings, but
  the symptoms correlated strongly with having a
  demanding job and lacking social support at work,
  said Mai Stafford, M.D., of the University
  College London Medical School here.
• symptoms were significantly associated with two
  psychosocial conditions having a demanding job
  and lacking supportive colleagues. Workers who
  reported having the most demanding jobs scored an
  average of nearly half a point higher on the
  symptom scale than those reporting the least
  demanding jobs (Plt.05).
• In addition, those reporting the lowest level of
  support at work also scored nearly half a point
  higher, compared with those reporting the highest
  level of support (Plt.05).
• Occupational and Environmental Medicine. 2006
  63(4)283-289.

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Indoor Air Quality and MCS

• Nonspecific Building Related Symptoms (BRS)
• Multiple Chemical Sensitivity (MCS)
• Exposure to toxic chemicals causes immune system
  to become sensitive to other chemicals/foods
• "Environmental illness," "total allergy
  syndrome," "20th century disease," "chemical
  AIDS.
• Clinical Ecologists diagnose and treat MCS
  patients
• Controversial
• Lack of scientific and clinical evidence
• Psychological or psychosocial factors
• Idiopathic Environmental Intolerance (IEI)
• A more appropriate term used by WHO, etc.

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Indoor Air Quality and MCS

• Nonspecific Building Related Symptoms (BRS)
• Multiple Chemical Sensitivity (cont.)
• American College of Occupational and
  Environmental Medicine (ACOEM) statement
• http//www.acoem.org/position/statements.asp
• ACOEM concurs with many prominent medical
  organizations that evidence does not yet exist to
  define MCS as a distinct entity.
• Because of uncertainties about both the etiology
  and pathophysiology of this condition, ACOEM
  believes that the term idiopathic environmental
  intolerance (IEI) more accurately reflects
  current state of knowledge.
• ACOEM continues to support the position that the
  relationship of MCS to environmental contaminants
  remains unproven.
• No scientific basis currently exists for
  investigating, regulating or managing the
  environment with the goal of minimizing the
  incidence or severity of MCS

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Indoor Air Quality and MCS

• The Building Environment
• Kinds of Buildings
• IAQ focus on non-industrial workplaces
• Relative Humidity (RH)
• Low RH blamed for some SBS symptoms
• Problems
• Most people are comfortable in lt25 RH
• High RH can cause IAQ problems
• Microorganism growth
• Dust mites (gt 60 RH)
• Condensation
• Thermal Comfort
• Affected by personal activity, clothing, air
  movement

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Indoor Air Quality and MCS

• The Building Environment
• Odors and Indoor Air Quality
• Odor is an important IAQ factor
• Perception of almost any odor in a supposedly
  clean environment will elicit a negative response
  in some people
• Especially a problem for unexpected odors
• Odor threshold concept
• Some chemical the odor threshold is near or above
  the hazard level
• Formaldehyde, acrolein, acetic acid, etc.
• Odor is a clear indication of hazard
• Other chemicals have odor threshold below the
  hazard level.
• Symptoms tend to by psychologically induced

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Indoor Air Quality and MCS

• Ventilation
• SBS occurs most often in mechanically ventilated,
  air conditioned buildings
• Inadequate outdoor air supply
• Effluents build up to levels where occupants
  perceive discomfort
• Psychological factors?
• Windows that dont open, contributing to lack of
  fresh air perception
• Occupants perceive physical discomfort to mean
  something is wrong

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Indoor Air Quality and MCS

• A 1987 NIOSH study found most IAQ problems were
  due to inadequate ventilation

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Indoor Air Quality and MCS

• Ventilation
• Heating, Ventilating, and Air Conditioning (HVAC)
  Systems
• HVAC function
• Provide adequate quality and quantity of outdoor
  air
• Filter, mix and distribute air to the occupied
  space
• Temperature and humidity control
• HVAC systems may be source of contamination
• CO, VOCs, fibers, particulates, biological
  pollutants
• Well-designed HVAC systems should provide air
  quality acceptable to the majority of occupants
• Design problems
• Insufficient outdoor air
• Inefficient filtration
• Inadequate cooling or dehumidification
• Etc.

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Indoor Air Quality and MCS

• Ventilation
• ASHRAE Ventilation Standards
• Standard 62-1989 specifies 15 ft2/min outside air
  per person (minimum)
• Previous standards allowed much less outside air
• Indoor/Outdoor Relationships
• Outdoor air is an important source of
  contamination
• Combustion products, ozone, fungus and bacteria
• Filtration
• Most HVAC systems pass the air through filters
• Most filters have minimal efficiency
• High efficiency filters are available
• Air filters can be a source of pollution
• Handling dirty filters can release particulates
• Wet filters can grow microorganisms

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Indoor Air Quality and MCS

• Ventilation
• Problems Maintaining Standard Ventilation
• Outdoor air quality may change
• Construction shortcuts
• Deliberate reductions in fresh air (early 1980s)
• Building renovation
• Increasing ventilation rates can decrease comfort
  
• Ventilation System Contamination
• Microbial contamination can cause BRD
• Always associated with water
• Cooling coil condensation
• Humidification
• Humidifiers can aerosolize contaminated water

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Indoor Air Quality and MCS

• Ventilation
• Fiber Glass in Ventilation Systems
• Fiber glass is used as sound insulation and to
  prevent condensation
• May become infested with bacteriological growth
• Unsealed fibrous materials should not be used
  where condensation or wetting is possible
• Assessing Ventilation Problems
• CO2 can be used to assess ventilation rates
• Outdoor air CO2 lt 400 ppm
• Indoor air CO2 gt 800 ppm is associated with IAQ
  complaints
• lt600 ppm good, gt 1000 ppm bad
• Indication of inadequate ventilation, not
  toxicity

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Indoor Air Quality and MCS

• Pollutant Categories
• Biological Agents
• Organisms
• Viruses cannot grow freely in the environment
• Bacteria
• Fungi
• Protozoa
• Arthropods
• Cockroaches
• Dust mites
• Birds and mammals
• Dander
• Plants
• Pollen

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Indoor Air Quality and MCS

• Pollutant Categories
• Biological Agents (cont.)
• Agents of Infection
• Health effects
• Contagious diseases
• Virulent environmental source infections
• Opportunistic infections
• Difficult to monitor for contagious or virulent
  infectious agents
• High-volume air sampling
• Cell or tissue culture with PCR analysis
• Not usually appropriate unless there is a
  compelling reason
• Levels of exposure are not as important as host
  risk factors
• Few standards
• Control by isolating infected or uninfected
  people, or removing reservoir

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Indoor Air Quality and MCS

• Pollutant Categories
• Biological Agents (cont.)
• Allergens
• Any protein, carbohydrate or glycoprotien gt
  10,000 daltons can act as an allergen
• Most are glycoprotiens
• Arthropods, mammals, birds, fungi, actinomycetes
• Pollen, latex
• Immune system responses
• Initial and subsequent exposure
• Hypersensitivity pneumonitis, allergic rhinitis,
  allergic asthma
• Monitored by bulk or air samples
• Immunoassay
• Culture
• Chemical analysis
• No exposure standards

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Indoor Air Quality and MCS

• Pollutant Categories
• Biological Agents (cont.)
• Biological Toxins
• Endotoxins
• From the cell walls of gram-negative bacteria
• Can cause shortness of breath, cough, fever,
  nausea
• Humidifier fever
• Monitoring by bulk or air samples
• No exposure standards
• Mycotoxins
• Air or bulk sampling for fungi
• No exposure standards
• Emphasis on mold contamination is probably
  misplaced
• Little evidence of harm

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Indoor Air Quality and MCS

• Pollutant Categories
• Non-biological Agents
• CO2
• Product of metabolism, combustion
• Asphyxiant at high levels (gt30,000 ppm)
• Indication of inadequate outdoor air ventilation
  (gt 800 ppm)
• CO
• Product of combustion
• Chemical asphyxiant
• Nitrogen and Sulfur Oxides (NO2, SO2)
• Vehicle and industrial emissions, cooking,
  combustion
• High NO2 (gt 200 pm) causes pulmonary edema
• Chronic NO2 can cause decreases lung function,
  etc.
• SO2 is an irritant, causes bronchoconstrictions
  in asthmatics

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Indoor Air Quality and MCS

• Pollutant Categories
• Non-biological Agents (cont.)
• Environmental Tobacco Smoke (ETS)
• Lung cancer risk, increased heart rate and blood
  pressure, birth defects, etc.
• Irritation, headache, rhinitis, coughing
• Other Non-biological Particles
• Airborne particulates
• Fibers
• Asbestos causes lung cancer, mesothelioma and
  asbestosis
• Fiber glass causes rash, itching, respiratory and
  eye irritation
• Ozone
• Combustion products, electrical devices
• Airway irritation, shortness of breath, headache,
  fatigue, etc.

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Indoor Air Quality and MCS

• Pollutant Categories
• Non-biological Agents (cont.)
• Formaldehyde
• Adhesives, building products, off gassing
• CSPC regulations have greatly reduced
  formaldehyde in building products
• Headache, eye and respiratory irritation,
  allergic response
• VOCs
• Bio-effluents, paints, cleaning products,
  personal care products, etc.
• Some VOCs are toxic
• VOC exposure is associated with SBS
• Radon
• Product of radioactive decay
• Radon decay products attach to particulates
• Lung cancer

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Indoor Air Quality and MCS

• Conclusions
• State of the Art
• Intensive ongoing research
• Controversial Topics
• Often no definitive data
• Undefined symptom complexes (MCS, etc.)
• Practical Guidance for Indoor Air Quality
  Investigations
• AIHA Practitioners Approach to Indoor Air Quality
  Investigations
• ACGIH Guidelines for the Assessment and Control
  of Bioaerosols
• AIHA Field Guide for Bioaerosols
• EPA Building Air Quality A Guide for Building
  Owners and Facility Managers