Indoor Air Quality Sean Mahar, PhD, CIH, CSP, PE
Problems Sick Building Syndrome AsthmaAllergies 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.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.The cause of the symptoms is not known. Most report relief soon after leaving the building.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.
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 sneezingsneezing congestioncongestion runny noserunny nose itchy nose, throat, eyes, and earsitchy nose, throat, eyes, and ears
Building Related Illnesses Include: Legionairres Disease (Legionllosis)Legionairres Disease (Legionllosis) Pontiac FeverPontiac Fever Humidifier FeverHumidifier 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 % CRC Handbook of Chemistry and Physics, 1997
Minor Components, Dry Air Neon 0.001818 % Methane 0.0002 % Helium 0.000524 % Krypton 0.000114 % Hydrogen 0.00005 % Xenon 0.0000087 % CRC Handbook of Chemistry and Physics, 1997
Airflow in buildings InfiltrationInfiltration ExfiltrationExfiltration
Contaminants Asbestos Carbon Dioxide (CO 2 ) Carbon Monoxide (CO) Formaldehyde (HCHO) Lead (Pb) Mold Nitrogen Dioxide (NO 2 ) Odor Ozone (O 3 ) Particles Radon (Rn) Sulfur Dioxide (SO 2 ) Volatile Organic Compounds (VOCs) Water Vapor
Asbestos Building materials, insulation Diseases of IAQ concern: Lung cancerLung cancer MesotheliomaMesothelioma UK Legislation CAWR requires assessment and management in all UK commercial properties a WARNING CONTAINS ASBESTOS Breathing asbestos dust is dangerous to health Follow safety instructions
Carbon Dioxide (CO 2 ) Often used as a surrogate for IAQ measures No health effects below 7000 to 20,000 ppmNo health effects below 7000 to 20,000 ppm As a surrogate it is kept below outdoor conc. + 700 ppmAs 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)3 ppm above outdoor level (alert) 9 ppm (health)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)120 µg/m3 (0.1 ppm) Based on irritation of sensitive people, 30- minute exposure (WHO).
Lead (Pb) Paint dust, outdoor air Recommended IAQ level 1.5 µg/m31.5 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 (NO 2 ) Leaking vented combustion appliances, unvented comb. appl. Outdoor air Recommended IAQ level 100 µg/m3100 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 CO 2 concentration can be used as a surrogate for occupant odors (odorous bioeffluents).
Ozone (O 3 ) Electrostatic appliances, Office machines, Ozone generators, Outdoor air Recommended IAQ level 100 µg/m3 (50 ppb)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)
Particles PM 10, PM 2.5, 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/liter4 pCi/liter Based on lung cancer, average exposure for 1 year. RnRnRnRn
Sulfur Dioxide (SO 2 ) Unvented space heaters (kerosene), outdoor air Recommended IAQ level 80 µg/m380 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/m 3 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)300-3000 µg/m3 (complaints possible) >3000 µg/m3 (complaints likely)>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 periodsHumidity 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.)(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 airDetermine fresh air Measure temperatureMeasure temperature Measure likely contaminantsMeasure likely contaminants –CO 2 as surrogate Question occupantsQuestion occupants
Summer Temp SourceTemptype Optimum, C Acceptable range, C CIBSE Guide A Dry resultant 2020-22 ANSI/ASHRAE 55-1992 Operative24.523-26
Winter Temp SourceTemptype Optimum, C Acceptable range, C CIBSE Guide A Dry resultant 2019-20 ANSI/ASHRAE 55-1992 Operative2220-23.5
MM40 Work EnvironmentWork Environment –Draught, temp odour, noise, etc. Work ConditionsWork Conditions –Interest, co-workers, etc. Past/Present Diseases SymptomsPast/Present Diseases Symptoms –Asthma, hay fever, etc. Work Environment SymptomsWork Environment Symptoms –Fatigue, headache, dry skin, etc.
Assessing Odors Odor assessmentOdor assessment Odor unitsOdor units Difficulties in assessing nuisance, in particular aspects such as aestheticsDifficulties 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/ m 3 ) 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/m 3, 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/m 3.
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.