NC Employees Workplace Program Requirements for. Safety and Health. Indoor Air Quality

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1 Purpose Purpose Indoor Air Quality The purpose of these requirements is to provide guidance to those responsible for preventing and solving problems of air quality in office buildings. Since problems vary widely in State agencies and universities, it follows that these requirements should be applied with flexibility according to the specific situation. No regulation of indoor air quality (IAQ) is in effect at this time. Scope Scope The scope of these requirements is limited to offices occupied by State employees. Building-related Illness, Sick Building Syndrome, and Multiple Chemical Sensitivity Syndrome. A building-related illness is a clinical illness for which a causative agent can be identified; e.g., Legionnaires disease, humidifier fever, hypersensitivity pneumonia, and building-related asthma. In contrast to building-related illnesses, no specific causative agent has been identified for the symptoms occurring in patients with the sick building syndrome (SBS). No one yet knows just how SBS is caused or what materials should be blamed except in those circumstances where a compound such as formaldehyde is found to be the cause of eye irritation or carbon monoxide the cause of headaches. Usually the syndrome shows an absence of clinical signs and diagnosis is based on self reported data. The myriad of symptoms reported in patients with the sick building syndrome include chest tightness, fatigue, headache, malaise, cough, as well as eye and mucus membrane irritation a rather vague group of non-specific problems. Stress and perception of air quality are important variables. Studies do show, however, that SBS is real and not imaginary. Its causes are likely multiple; synergism of one chemical with another or with a bioaerosol may be a significant source, perhaps confounded with allergy. Symptoms are relieved when the employee leaves the building. Multiple chemical syndrome (MCS) patients present a constellation of symptoms; e.g., depression, fatigue, irritability, difficulty in breathing, headaches, gastrointestinal distress, food intolerance. There are at this time no well-controlled studies establishing a clear mechanism or cause for the MCS syndrome. The American Medical Association in 1991 concluded that MCS should not be considered a recognized clinical syndrome. MCS has been listed as a disability by the U.S. Congress under the Americans with Disabilities Act and since then the number of cases has grown exponentially. Complaints about IAQ depend on gender and job. Women in clerical jobs have the highest rate. Regulations and Guidelines for Indoor Air Quality No regulation of indoor air quality (IAQ) is in effect at this time. OSHA is attempting to codify a solution to indoor air quality problems. The statutory general duty clause contemplates serious IAQ issues. SBS symptoms have been reported even though exposures to gases, vapors, and dusts have been minuscule when compared to exposures

2 of factory workers to similar substances. Regardless of the reason, standards for the air environment stricter for offices than for factories are being sought. The indoor air quality standard of the American Society of Heating, Refrigerating and Air- Conditioning Engineers called Ventilation for Acceptable Indoor Air Quality is the guideline widely used in evaluating indoor air quality. For contaminants where standards have not been established, ASHRAE specifies that it has been customary to assume as a first guide that a concentration of 0.1 the permissible exposure limit value would not produce complaints in a nonindustrial population. Chemicals Present in Indoor Air There is no such thing as pure air. Air always has had, and will always have, some contaminants from both natural and man-made sources. There is, however, limited scientific knowledge of the relationship between air pollution and health effects. Chemicals present in building offices can arise either from indoors or from outdoors and are emitted from continuous, instantaneous, or local sources. They are related to occupancy and occupant activity, to the building, or to the outside air, or to all three. Chemicals most likely to arise indoors include airborne dust, nicotine (used as a tobacco smoke indicator), volatile organic compounds, formaldehyde, carbon monoxide, carbon dioxide (used as an indicator of the effectiveness of ventilation), ozone, and radon. Among the outdoor pollutants are nitrogen, sulfur, and carbon oxides which are introduced by the ventilation system and by infiltration. Dust concentrations are related mainly to occupant activity which contributes to the generation of airborne suspensions of these particulates. Thus, higher values are obtained in offices where occupant density and circulation are high. Dust also enters by infiltration or, if HVAC system filters are inefficient, by mechanical ventilation. The composition is typically paper, cotton, wool, and other synthetic fibers and mineral dusts. There is no theoretical reason why concentrations of dust usually found in indoor air should be related to effects on an occupant s health. Cigarette smoke can be a significant particulate emissions source and can when it is present produce adverse health effects. Environmental tobacco smoke may also be an important emission source of volatile organic compounds (VOCs)in the indoor air. Other sources of volatile compounds are numerous and not easy to quantify individually. They include products used for construction, renovation, or maintenance; products used or generated by occupants; pesticides; products emitted by other activities in the building; and products generated outside the building. With the exception of benzene (which is capable of causing leukemia in man), none of the VOCs associated with IAQ have any health effect on man in the concentrations usually encountered or, in fact, in concentrations orders of magnitude greater than those found. ASHRAE recommends an 8-hour TWA of 1 ppm for VOCs in indoor air. Most sulfur dioxide inside buildings appears to come from polluted air outdoors; if the EPA ambient air quality standard is met outdoors, there is little chance of it being exceeded indoors. Sulfur dioxide is rapidly sorbed onto surfaces within buildings and therefore its concentration indoors is almost always less than outdoors. Formaldehyde is emitted by construction and furniture materials, especially plywood, and in cigarette smoke. ASHRAE recommends an 8-hour TWA of 0.4 ppm in indoor air.

3 The main source of nitrogen dioxide and carbon monoxide in buildings is motor vehicle exhaust near an air intake or within the building. ASHRAE recommends an 8-hour TWA of 9 ppm for carbon dioxide in indoor air. The main source of ozone in buildings is usually ozone in the outside air. However, office buildings usually have a few photocopiers and these machines may generate sufficient ozone to be troublesome, particularly in older machines. When these machines are equipped with local ventilation, no ozone is detected. Otherwise values up to 135 ppb at the exhaust outlet and 45 ppb in the user s respiratory zone may be found. Electrostatic precipitators used for dust control and germicide and deodorizer devices may be other internal sources. The Food and Drug Administration prohibits devices such as germicides and deodorizers that result in more than 50 ppb of ozone indoors. Ozone is reactive with many things, including most surfaces and even other materials in the air. For that reason its concentration decreases rapidly in almost all environments unless there is a local source nearby. The odor threshold for ozone is 20 to 50 ppb, well below the 120 ppb peak represented by the ASHRAE limit That odor often draws objections when it is present. Control of odor annoyance from ozone may prove to be more important in tight buildings than control to avoid health effects. In office buildings, the main source of carbon dioxide is human respiration, and resulting concentrations depend on the number of occupants and the volume of outdoor air introduced by the ventilation system. Therefore, the carbon dioxide concentration is a crude indicator of whether or not sufficient fresh air is being supplied to dilute contaminants and odors. Concentrations usually peak at the end of the morning and at the end of the working day, following occupancy patterns. OSHA proposes to limit continuous carbon dioxide concentrations to 800 ppm and ASHRAE recommends a continuous limit of 1000 ppm. Carbon dioxide is not considered a health risk at these levels but is a surrogate for human comfort (odor). Radon enters buildings mainly by infiltration through foundation cracks and is a function of the geologic nature of the site. Bioaerosols Present in Indoor Air There are six types of bioaerosols: (1) bacteria, (2) fungi such as mold, mildew, etc., (3) viruses, rickettsia, chlamydia, and mycoplasma, (4) amoeba, (5) insects (proteins in the droppings and carcasses of dust mites and the German cockroach are reportedly a major trigger and cause of asthma), and (6) pollens. With few exceptions, microorganisms grow only between 40 and 110 F and they require moisture for growth. In conditions of high relative humidity, generally greater than 80%, some fungi may obtain moisture requirements from the air. OSHA is proposing that the relative humidity be kept below 60% in office buildings. Accumulations of dirt, dust, and dead biological matter may serve as nutrients for microbial growth. There are different opinions about whether or not plants are a source of microbial contamination. Any porous material that becomes wet can promote fungal growth; e.g., cellulose ceiling tiles and wall boards. Fungi are common contaminants of indoor air and dust in homes as well as in workplaces. They generally are brought in with the outdoor air.

4 Air Monitoring Air Monitoring NC Employees Workplace Program Requirements for While most chemical contaminants are measurable, they are, for the most part, not detectable to occupants. However, except in the very few cases where the contaminant is a single source, sampling will not usually prove to be helpful. Generally after a battery of expensive tests, the industrial hygienist recommends that the outdoor ventilation rate be increased until most of the occupants are satisfied. Sampling for carbon dioxide can, however, be useful since most complaints are about insufficient ventilation and this in turn relates to complaints about temperature and stale air. High levels of carbon dioxide (>800 ppm) tend to indicate that not enough fresh air is being supplied to the occupied spaces. OSHA has suggested that carbon dioxide be used as an IAQ index because it is normally present in measurable levels (outside air normally contains about 350 ppm), can be readily measured, and is directly related to the occupancy of the area. If the outside air ventilation rate is insufficient to dilute and remove carbon dioxide then it can be assumed that other contaminant concentrations will also be elevated. This is the present status of bioaerosol monitoring: 1. There are no established guidelines. No governmental or industry guidelines as to acceptable levels in normal and problem buildings exist. 2. Proactive monitoring is discouraged by the Centers for Communicable Disease Control and Prevention because of problems in interpreting data. 3. Generally, environmental microbiological sampling is not conducted until there is epidemiological evidence pointing to an outbreak and even then it is sometimes discouraged because of the difficulty in interpreting the data. 4. Analytical methods are not uniform among laboratories and there is no accreditation program for laboratories engaged in bioaerosol analysis. I Indoor Air Quality Assessment These are steps in an IAQ assessment: 1. Document employee complaints to target problem areas and assure employees that something is being done to remedy the situation. 2. Visually inspect the problem area. Look for point sources and pollutants in outside air. 3. Develop a description of the building and its history. 4. Examine and balance the HVAC system. Mechanical ventilation systems control the entry of outdoor air in modern office buildings. Open windows are rare these days. It is important to find out if the existing HVAC system has been operated and maintained to at least design specifications. Symptoms often decrease once the mechanical system is maintained and properly balanced. Ventilation rates are based primarily on the need to control odors and carbon dioxide levels i.e., occupant generated contaminants or bioeffluents. Effectiveness depends on the efficiency of the system the air distribution and mixing. 5. Measure temperature and relative humidity. Temperature is the air quality most important to comfort and well-being. A wide range of temperatures can be linked to poor air circulation and improper air balancing. The condition of elevated temperature and unequal air movement is frequently confused with the presence of pollutants in the air. Exposure to temperatures outside the comfort range can produce such adverse health effects as

5 headache, giddiness, and fatigue. People cannot detect relative humidity unless subject to extreme levels. In fact, studies show that over a range of about 15% to 50%, men are hopeless at judging relative humidity. There is a significant correlation for women and it is negative so the higher the humidity, the dryer women report it is. 6. Sample the air if no other explanation of the complaints has been discovered although there is virtually no relationship between any symptoms and any contaminants. The survey report will most often contain inconclusive results since the things commonly measured are comfort limits and do not satisfy the occupants because a specific problem or source was not discovered. IAQ complaint usually have some basis, although they are often difficult to assess with specificity. Prohibiting smoking immediately eliminates one of the prime sources of air pollution. The World Health Organization cites the cigarette as the #1 source of indoor air pollution. Lack of windows, noise, inadequate light, ergonomic factors, and intensive use of VDTs will cause discomfort in occupants that may be inaccurately attributed to air quality. What employees are typically reporting are comfort ventilation issues, not toxic exposure issues. Poor management and boring work lower the threshold for complaint. Psychological overlay is common. Where special problem exist, such as in isolation rooms for tuberculosis patients, air purification and filtering systems are needed. Indoor Air Quality Management and Remediation IAQ management and control needs to be part of the building s overall maintenance program. Written operations that describe daily operation and management of building systems and maintenance are useful to manage IAQ. They include information on: 1. The minimum outside air ventilation rate. The HVAC system should provide at least 5 cfm/person so that the carbon dioxide concentration does not exceed 800 ppm. 2. Maximum relative humidity. Humidity should not exceed 60%. 3. Temperature range. Temperature should be between 68 F and 78 F. 4. Things to check for visually such as plugged drains on cooling coil condensate drip pans (resulting in microbial contamination), failed exhaust fans in underground parking garages, failed exhaust fans on local exhausts where air contaminants are emitted, microbial fouling of cooling tower water from lack of water treatment with biocide, failure of the automatic temperature control system resulting in lack of outside ventilation air, dust and particulate matter visible in the air, dirty bathrooms, smell of sewer gas, mold, vehicular fumes, evidence of insect infestation, general housekeeping, water leaks, ventilation problems evident when odors linger, leaky faucets, wet carpets, cleanliness of mechanical equipment rooms and any non-ducted air plenums or chases. 5. Procedures to be used during renovation to maintain IAQ. Control of pollutants at the source e.g., a no smoking policy is the most effective strategy for maintaining clean indoor air. General ventilation is second. Other improvements may be needed to maintain IAQ such as: 1. Relocating air intakes and other pathways of building entry to restrict the entry of outdoor air contaminants. 2. Installing local source capture exhaust ventilation or substitution within workspaces where air contaminants are being emitted. 3. Increasing ventilation effectiveness, reducing unwanted infiltration, and monitoring outside air quantity to meet ventilation requirements.

6 4. Rearranging the area, redesigning the distribution system, or boosting the HVAC supply to an area where the air is stagnant. 5. Airing-out vapor contaminants immediately following installation of new materials and selecting low irritation materials to begin with. 6. Addressing bioaerosol amplification factors. 7. Installing effective, efficient, and maintainable ventilation systems preferably with floorlevel exhausts that can improve mixing and help move the concentration gradient of contaminants downward, away from breathing zones. 8. Providing for other factors such as lighting, ergonomics. and good employee relations. Where there are a number of different lessees located in separate leased spaces within the same building, the lessees share responsibility for managing IAQ. It is up to the lessee to provide the building owner with a description of the work activity planned including the number of employees or visitors expected, the hours of work, and situations where air contaminants may be released e.g., new furniture or painting. The owner can operate the HVAC system to provide the required air ventilation rate and desired relative humidity. Resources U. S. EPA - An Office Building Occupant's Guide to Indoor Air Quality Centers for Disease Control