Transcript HL1115 Influences on Health at Work

Indoor Air Quality
Sean Mahar, PhD, CIH, CSP, PE
Problems
Sick Building Syndrome
Asthma
Allergies
Building Related Illnesses
Sick Building Syndrome
In "sick building syndrome" (SBS) building
occupants experience acute health and
comfort effects that appear to be linked to
time spent in a building, but no specific
illness or cause can be identified.
In "building related illness" (BRI) symptoms
of diagnosable illness are identified and
can be attributed directly to airborne
building contaminants
Sick Building Syndrome
•
Occupants complain of symptoms
associated with acute discomfort, e.g.,
headache; eye, nose, or throat irritation;
dry cough; dry or itchy skin; dizziness and
nausea; difficulty in concentrating; fatigue;
and sensitivity to odors.
•
The cause of the symptoms is not known.
•
Most report relief soon after leaving the
building.
Asthma
Characterized by episodes of airflow
obstruction in the bronchial tubes.
Symptoms caused by this obstruction include
coughing, chest tightness, wheezing and
shortness of breath.
Although problems are often separated by
symptom-free periods, asthma is a
chronic illness.
Common Asthmagens
•
•
•
•
•
•
•
Isocyanates
Solder fume
Metals
Latex
Vegetable dusts
Animal proteins
Enzymes
Allergic Reactions
Include:
• Allergic Alveolitis
• Rhinitis
Allergic Alveolitis
Also known as:
Hypersensitivity Pneumonitis (HP) or
Extrinsic Allergic alveolitis (EAA)
Other names include:
• farmers lung
• bagassosis
• pigeon fanciers lung
Allergic Alveolitis
Acute symptoms include fever, chills,
dyspnea, leukocytosis 4-6 hours after
exposure and may recur on re-exposure.
Chronic disease shows progressive
dyspnea, fatigue, low-grade fever, weight
loss, chronic nonproductive cough, and
bibasilar crackles.
Allergic Alveolitis
a restrictive type impairment
type III and IV hypersensitivity reaction
Farmers Lung
source: moldy crops
organisms:
Thermoactinomyces
sacchari
Thermoactinomyces
vulgaris
Micropolyspora faeni
Bagassosis
source: moldy sugar
cane
organisms:
Thermoactinomyces
vulgaris
Micropolyspora faeni
Aspergillus species
Pigeon Fancier’s Lung
source: pigeon dust
and bloom
substance:
proteins
Rhinitis
A reaction that occurs in the eyes, nose
and throat when airborne irritants or
allergens trigger the release of
histamine.
Histamine causes inflammation and fluid
production in the fragile linings of
nasal passages, sinuses, and eyelids.
Rhinitis
•
•
•
•
sneezing
congestion
runny nose
itchy nose,
throat, eyes,
and ears
Rhinitis
Allergic rhinitis
• pollen
• dust mites
• mold
• animal dander
Rhinitis
Nonallergic rhinitis
• fumes
• odors
• temperature
• smoke
• other irritants
Building Related Illnesses
Include:
• Legionairres Disease
(Legionllosis)
• Pontiac Fever
• Humidifier Fever
Legionella pneumophila
Discovered in 1976 when an outbreak of
pneumonia at an American Legion
convention in Philadelphia led to 29
deaths.
Causative agent for both Legionellosis
and Pontiac Fever
Legionella pneumophila
motile, Gram-negative,
anaerobic rod
reproduce to high numbers
in warm, stagnant water
(90°-105° F)
Legionellosis
Symptoms include fever, chills, and a
cough, which may be dry or may
produce sputum.
Can also include muscle aches,
headache, tiredness, loss of appetite,
and, occasionally, diarrhea.
Laboratory tests may show kidney
function abnormalities.
Legionellosis
Chest X-rays often show pneumonia.
Difficult to distinguish from other types of
pneumonia by symptoms alone.
Time between exposure to the bacterium
and the onset of illness is 2 to 10
days.
Legionellosis
Middle-aged and older persons,
particularly those who smoke
cigarettes or have chronic lung
disease at primary risk.
Immunocompromised people (AIDS,
cancer patients, etc ) also at
increased risk.
Pontiac Fever
Symptoms include fever and muscle
aches and do not have pneumonia.
Recovery in 2 to 5 days without
treatment.
Time between exposure and illness
generally a few hours to 2 days
Anyone is at risk
Primary Components, Dry Air
Nitrogen 78.084 %
Oxygen 20.9476 %
Argon 0.934 %
Carbon Dioxide
0.0314 %
Carbon
Dioxide
Argon
Oxygen
Nitrogen
CRC Handbook of Chemistry and Physics, 1997
Minor Components, Dry Air
Neon 0.001818 %
Xenon
Methane 0.0002 %
Helium 0.000524 %
Krypton 0.000114 %
Hydrogen
Krypton
Hydrogen 0.00005 %
Helium
Xenon 0.0000087 %
Methane
Neon
CRC Handbook of Chemistry and Physics, 1997
Airflow in buildings
• Infiltration
• Exfiltration
Contaminants
Asbestos
Carbon Dioxide (CO2)
Carbon Monoxide
(CO)
Formaldehyde (HCHO)
Lead (Pb)
Mold
Nitrogen Dioxide (NO2)
Odor
Ozone (O3)
Particles
Radon (Rn)
Sulfur Dioxide (SO2)
Volatile Organic
Compounds (VOCs)
Water Vapor
Asbestos
Building materials, insulation
Diseases of IAQ concern:
• Lung cancer
a
WARNING
CONTAINS
ASBESTOS
Breathing
asbestos dust is
dangerous to
health
Follow safety
instructions
• Mesothelioma
UK Legislation CAWR requires assessment and
management in all UK commercial properties
Carbon Dioxide (CO2)
Often used as a surrogate for IAQ measures
• No health effects below 7000 to 20,000 ppm
• As a surrogate it is kept below outdoor conc.
+ 700 ppm
Maintaining CO2 concentrations within 700 ppm
of outdoors should provide acceptable
perceived air quality in terms of human body
odor, it does not necessarily imply adequate
control of these other pollutant sources
Carbon Monoxide (CO)
Leaking vented combustion appliances, unvented
combustion appliances, parking garages
Recommended IAQ level
• 3 ppm above outdoor level (alert)
• 9 ppm (health)
Alert level an indication of abnormal indoor
concentration;
Health level based on effects on persons with
coronary artery disease, average exposure for 8
hours.
Formaldehyde (HCHO)
Pressed-wood products, furniture and
furnishings
Recommended IAQ level
• 120 µg/m3 (0.1 ppm)
Based on irritation of sensitive people, 30minute exposure (WHO).
Lead (Pb)
Paint dust, outdoor air
Recommended IAQ level
• 1.5 µg/m3
Based on adverse effects on
neuropsychological functioning of children,
average exposure for 3 months (WHO: 0.5-1
µg/m3 for 1 year).
Nitrogen Dioxide (NO2)
Leaking vented combustion appliances,
unvented comb. appl. Outdoor air
Recommended IAQ level
• 100 µg/m3
Based on providing protection against adverse
respiratory effects, average exposure for 1
year.
Odor
Occupants, fungal (mold) sources, VOC
sources, outdoor air
Predicted acceptability to 80% or more of
occupants or visitors
CO2 concentration can be used as a surrogate
for occupant odors (odorous bioeffluents).
Ozone (O3)
Electrostatic appliances, Office machines,
Ozone generators, Outdoor air
Recommended IAQ level
• 100 µg/m3 (50 ppb)
Based on potential for adverse acute and
chronic effects, and an additional margin of
protection, 8-hr exposure (WHO); continuous
exposure (FDA)
Mold
Current bogeyman of US IAQ community
Particles
PM10, PM2.5, Dust, Smoke, Deteriorating
materials, Outdoor air 50 µg/m3
Based on protecting against respiratory
morbidity in the general population and
avoiding exacerbation of asthma, average
exposure for 1 year, no carcinogens. Indoor
concentrations are normally lower; guideline
level may lead to unacceptable deposition of
"dust."
Radon (Rn)
Soil gas
Recommended IAQ level
• 4 pCi/liter
Based on lung cancer, average
exposure for 1 year.
R
n
Sulfur Dioxide (SO2)
Unvented space heaters (kerosene), outdoor air
Recommended IAQ level
• 80 µg/m3
Based on protecting against respiratory
morbidity in the general population and
avoiding exacerbation of asthma, average
exposure for 1 year (WHO: 50 µg/m3 if with
PM)
Volatile Organic Compounds
(VOCs)
organic (carbon-based) compounds that
evaporates at ambient temperatures
New building materials and furnishings,
consumable products, maintenance
materials, paint, mold, outdoor air
Recommended IAQ level
• 300-3000 µg/m3 (complaints possible)
• >3000 µg/m3 (complaints likely)
Volatile Organic Compounds
(VOCs)
Odor and irritation responses to organic
compounds are highly variable. The three
guidelines for this class of compounds
represent ranges where odor and irritation
complaints are seldom observed (comfort
range); where complaints can become
significant in buildings (comfort - discomfort
range); and where significant complaints are
likely (discomfort range). Average indoor
concentrations in most buildings are well
below 1000 µg/m3.
Water Vapor
• Humidity shouldn't exceed 60% during
occupied periods, and no greater than 70%
during unoccupied periods
• (to minimize the potential for microbial growth
in indoor spaces. Moisture is the primary
factor that limits the growth of fungi on
construction and finishing materials.)
Diagnosis
• Determine fresh air
• Measure temperature
• Measure likely contaminants
– CO2 as surrogate
• Question occupants
Summer Temp
Source
Temp
CIBSE
type
Dry
resultant
Guide A
ANSI/ASHRAE Operative
55-1992
Optimum, Acceptable
C
range, C
20
20-22
24.5
23-26
Winter Temp
Source
Temp
CIBSE
type
Dry
resultant
Guide A
ANSI/ASHRAE Operative
55-1992
Optimum, Acceptable
C
range, C
20
19-20
22
20-23.5
Humidity
Source
Relative humidity range, %
CIBSE
40-70
Guide A
ANSI/ASHRAE
55
30-60
Fresh Air
Source
Outdoor Air, l/s/occupant
CIBSE
8
Guide B
ANSI/ASHRAE
62-1989
10
Question Occupants
• NIOSH I-BEAM
• Stockholm Indoor Environment
Questionnaire
• MM40
MM40
• Work Environment
– Draught, temp odour, noise, etc.
• Work Conditions
– Interest, co-workers, etc.
• Past/Present Diseases Symptoms
– Asthma, hay fever, etc.
• Work Environment Symptoms
– Fatigue, headache, dry skin, etc.
Assessing Odors
• Odor assessment
• Odor units
• Difficulties in assessing nuisance, in
particular aspects such as aesthetics
Assessing Odors
Odor concentration
The number of odor units per unit of
volume. The numeric value of the odor
concentration, expressed in odor units (E/
m3) equals the number of times that the
air should be treated with odorless air to
reach the odor threshold.
Assessing Odors
Odor threshold
The concentration of a gaseous
substance, expressed in µg/m3, which will
be discerned from odorless air by at least
half of an odor panel. The odor threshold
per definition has an odor concentration
of 1 odor unit/m3.
Assessing Odors
Odor standard
A standard for odor, expressed as a
maximum concentration, which may not
be crossed.
Assessing Odors
Serious odor nuisance
A degree of odor nuisance which exceeds
the maximum admittable level for human
health. Both health effects and personally
experienced effects play a part here. In
practice a level of odor nuisance is
determined by questionnaires in which
people can describe the degree of odor
nuisance they have experienced.
Assessing Odors
Zero-effect level
This is the highest possible odor
concentration in which people do not
experience odor nuisance yet.
Questions?