INDOOR AIR QUALITY ASSESSMENT
Gerena Magnet School
200 Birnie Street
Massachusetts Department of Public Health
Center for Environmental Health Bureau of Environmental Health Assessment
At the request of Judy Dean, Western Massachusetts American Lung Association, the Massachusetts Department of Public Health (MDPH), Center for Environmental Health’s (CEH) Bureau of Environmental Health Assessment (BEHA) provided assistance and consultation regarding indoor air quality at the Gerena Magnet School (GMS), 200 Birnie Street, Springfield, Massachusetts. Nursing staff at this school raised concerns about indoor air quality, especially in the special needs classroom area.
On February 13, 2004, a visit to conduct an indoor air quality assessment was made to this school by Michael Feeney, Director of Emergency Response/Indoor Air Quality (ER/IAQ), BEHA. Mary Zamorski, Nursing Supervisor, Springfield School Department and Ms. Dean accompanied Mr. Feeney during this evaluation.
The GMS is a two-story complex reportedly constructed in 1975. The complex consists of a main building, which spans the length of the Interstate Highway 91 (I-91) overpass, and an underground structure referred to as the GMS Annex (Map 1). The main GMS building is the subject of this report, whereas the GMS Annex is the subject of a separate report.
The GMS main building consists of general classrooms, art rooms, science classrooms, library, auditorium and main office area. Classrooms are arranged in a “pod” system, with four-foot dividers, shelves and/or walls serving as partitions in large open room. The center of the building contains a large, multiple story, enclosed atrium (Picture 1). The atrium provides access to the GMS Annex, as well as the cafeteria and additional classrooms situated in the underground level. Classroom areas along exterior walls have
openable windows. No openable windows exist in the underground areas of the GMS main building.
Air tests for carbon dioxide, carbon monoxide, temperature and relative humidity were taken with the TSI, Q-TRAK? IAQ Monitor, Model 8551. Air tests for airborne
particle matter with a diameter less than 2.5 micrometers were taken with the TSI, DUSTTRAK? Aerosol Monitor Model 8520. Screening for total volatile organic compounds (TVOCs) was conducted using a Thermo Environmental Instruments Inc., Model 580 Series Photo Ionization Detector (PID).
The GMS has approximately 800 students in pre-kindergarten through fifth grade and a staff of approximately 60. Tests were taken at the school during normal operations. Test results appear in Table 1.
It can be seen from Table 1 that carbon dioxide levels were elevated above 800 ppm (parts per million) in five of twenty-three areas surveyed, indicating a ventilation problem in some areas of the school. It should be noted however, that a number of areas with carbon dioxide levels below 800 ppm had either open windows or were sparsely populated. These factors can greatly contribute to the reduction of carbon dioxide levels.
Mechanical ventilation is provided by a heating, ventilating and air conditioning (HVAC) system. Fresh air to classroom pods is provided by rooftop-mounted AHUs (Picture 2). Supply ducts connect the AHUs to the ceiling mounted air diffusers, which are located in light fixtures of each room (Picture 3). Air diffusers are equipped with fixed louvers that direct the air supply along the ceiling and down walls. In this manner, airflow is created. Exhaust ventilation throughout the building is provided by ceiling and/or wall-mounted exhaust vents.
Unit ventilator systems (univents) supply fresh air to small classroom areas, or minipods (Picture 4) (Table 1). Univents draw air from outdoors through a fresh air intake located on the exterior walls of the building and return air through an air intake located at the base of each unit (Figure 1). Fresh and return air are mixed, filtered, heated and
provided to classrooms through an air diffuser located in the top of the unit. Univents have three controls: low, high and off. Univents were turned off in classrooms throughout the school. In order for univents to provide fresh air as designed, these units must remain “on” and allowed to operate while rooms are occupied. Furthermore, intakes must remain free of obstructions.
In order to have proper ventilation with a mechanical supply and exhaust system, these systems must be balanced to provide an adequate amount of fresh air to the interior of a room while removing stale air from the room. It is recommended that existing ventilation systems be re-balanced every five years to ensure adequate air systems function (SMACNA, 1994). According to school department officials, the date of the last balancing of these systems was not available at the time of the assessment.
The Massachusetts Building Code requires that each room have a minimum ventilation rate of 15 cubic feet per minute (cfm) per occupant of fresh outside air or openable windows (SBBRS, 1997; BOCA, 1993). The ventilation must be on at all times a room is occupied. Providing adequate fresh air ventilation with open windows and maintaining the temperature in the comfort range during the cold weather season is impractical. Mechanical ventilation is usually required to provide adequate fresh air ventilation.
Carbon dioxide is not a problem in and of itself. It is used as an indicator of the adequacy of the fresh air ventilation. As carbon dioxide levels rise, it indicates that the ventilation system is malfunctioning or the design occupancy of the room is being exceeded. When this happens a buildup of common indoor air pollutants can occur, leading to discomfort or health complaints. The Occupational Safety and Health Administration (OSHA) standard for carbon dioxide is 5,000 parts per million parts of air (ppm). Workers may be exposed to this level for 40 hours/week based on a time-weighted average (OSHA, 1997).
The Department of Public Health uses a guideline of 800 ppm for publicly occupied buildings. A guideline of 600 ppm or less is preferred in schools due to the fact that the majority of occupants are young and considered to be a more sensitive population in the evaluation of environmental health status. Inadequate ventilation and/or elevated temperatures are major causes of complaints such as respiratory, eye, nose and throat irritation, lethargy and headaches. For more information concerning carbon dioxide, please consult Appendix A.
oo F to 74 F, which were within the BEHA Temperature readings ranged from 70
recommended comfort range. The BEHA recommends that indoor air temperatures be
o omaintained in a range of 70 F to 78 F in order to provide for the comfort of building
occupants. In many cases concerning indoor air quality, fluctuations of temperature in occupied spaces are typically experienced, even in a building with an adequate fresh air supply.
The relative humidity in the building ranged from 16 to 19 percent, which was below the BEHA recommended comfort range. The BEHA recommends a comfort range of 40 to 60 percent for indoor air relative humidity. Relative humidity levels in the building would be expected to drop during the winter months due to heating. The sensation of dryness and irritation is common in a low relative humidity environment. Low relative humidity is a very common problem during the heating season in the northeast part of the United States.
A letter detailing possible mold contamination identified in classrooms in the GMS and Annex was issued by BEHA prior to this report (Appendix B) (MDPH, 2004). Of note is water penetration in below grade areas, directly beneath the footprint of the school. The rear wall of the atrium showed signs of efflorescence and peeling paint (Picture 5), which indicate water penetration. Efflorescence is a characteristic sign of water damage to brick and mortar, but it is not mold growth. Brick, cement and mortar are not generally good mold growth media. As moisture penetrates and works its way through mortar and brick, water-soluble compounds in brick and mortar dissolve, creating a solution. As the solution
moves to the surface of brick or mortar, the water evaporates, leaving behind white, powdery mineral deposits.
In contrast to brick and cement, ceiling tiles can be a mold growth medium, particularly if moistened repeatedly without drying. Of note were missing ceiling tiles due to water damage in the pod area below the media center. Ceiling tiles along the exterior (foundation) wall were missing in this room. The US Environmental Protection Agency (US EPA) and the American Conference of Governmental Industrial Hygienists (ACGIH) recommends that porous materials be dried with fans and heating within 24 to 48 hours of becoming wet (ACGIH, 1989; US EPA, 2001). If porous materials are not dried within this time frame, mold growth may occur. Cleaning cannot adequately remove mold growth from water damaged porous materials. The application of a mildewcide to moldy porous materials (e.g., ceiling tiles) is not recommended.
The grounds around the GMS building exterior may also provide a source of moisture. Railroad tracks parallel the rear of the school. A chain link fence separates the tracks and the building (Picture 6). Trees, weeds, and standing water were seen in the gap between the building and the tracks. The growth of roots against exterior walls can bring moisture in contact with the walls, which can eventually lead to cracks and/or fissures in the foundation below ground level. Over time, this process can undermine the integrity of the building envelope and provide a means of water entry into the building through foundation concrete and masonry via capillary action (Lstiburek & Brennan, 2001).
A bird was noted to be roosting on the exterior window framework of the atrium, and bird waste was seen on the side of atrium window on interior support beams (Picture 7). Bird wastes in a building raise concerns because of diseases that may be caused by
exposure to bird wastes. Certain molds associated with bird waste are of concern, especially for immune-compromised individuals. Other diseases of the respiratory tract may also result from chronic exposure to bird waste. Exposure to bird wastes is thought to be associated with the development of hypersensitivity pneumonitis in some individuals. Psittacosis (bird fancier's disease) is another condition closely associated with exposure to bird wastes in either the occupational or bird raising setting. While immune-compromised individuals have an increased risk of health impacts following exposure to the materials in bird wastes, these impacts may also occur in healthy individuals exposed to these materials. Considering the health affects of bird wastes, the need for clean up of bird waste and appropriate disinfection is imperative.
The methods to be employed in clean up of a bird waste problem depend on the amount of waste and the types of materials contaminated. The MDPH has been involved in several indoor air investigations where bird waste has accumulated within ventilation ductwork (MDPH, 1999). Accumulation of bird wastes has required clean up of such buildings by a professional cleaning contractor. In less severe cases, the cleaning of the contaminated material with a solution of sodium hypochlorite has been an effective disinfectant (CDC, 1998). Disinfection of non-porous materials can be readily accomplished with this material. Porous materials contaminated with bird waste should be examined by a professional restoration contractor to determine if the material is salvageable. Where a porous material has been colonized with mold, it is recommended that the material be discarded (ACGIH, 1989).
The protection of both the cleaner and other occupants present in the building must be considered as part of the overall remedial plan. Where cleaning solutions are to be used,
the “cleaner” is required to be trained in the use of personal protective methods and equipment (to prevent either the spread of disease from the bird wastes and/or exposure to cleaning chemicals). In addition, the method used to clean up bird waste may result in the aerosolization of particulates that can spread to occupied areas via openings (doors, etc.) or by the ventilation system. Methods to prevent the spread of bird waste particulates to occupied areas or ventilation ducts must be employed. In these instances, the result can be similar to the spread of renovation-generated dusts and odors in occupied areas. To prevent this, the cleaner should employ the methods listed in the SMACNA Guidelines for Containment of Renovation in Occupied Buildings (SMACNA, 1995).
Lastly, several areas had plants. A number of these plants did not have drip pans. Plant soil and drip pans can serve as a source of mold growth. Plants should be properly maintained and equipped with drip pans. Plants should also be located away from the air stream of mechanical ventilation to prevent aerosolization of dirt, pollen or mold.
Indoor air quality can be adversely impacted by the presence of respiratory irritants, such as products of combustion. The process of combustion produces a number of pollutants. Common combustion products include carbon monoxide, carbon dioxide, water vapor and smoke (fine airborne particle material). Of these materials, exposure to carbon monoxide and particulate matter with a diameter of 2.5 micrometers (μm) or less (PM2.5) can produce immediate, acute health effects upon exposure. To determine whether combustion products were present in the school environment, BEHA staff obtained measurements for carbon monoxide and PM2.5.
Carbon monoxide is a by-product of incomplete combustion of organic matter (e.g., gasoline, wood and tobacco). Exposure to carbon monoxide can produce immediate and acute health affects. Several air quality standards have been established to address carbon monoxide and prevent symptoms from exposure to these substances. The MDPH established a corrective action level concerning carbon monoxide in ice skating rinks that use fossil-fueled ice resurfacing equipment. If an operator of an indoor ice rink measures a carbon monoxide level over 30 ppm, taken 20 minutes after resurfacing within a rink, that operator must take actions to reduce carbon monoxide levels (MDPH, 1997).
ASHRAE has adopted the National Ambient Air Quality Standards (NAAQS) as one set of criteria for assessing indoor air quality and monitoring of fresh air introduced by HVAC systems (ASHRAE, 1989). The NAAQS are standards established by the US EPA to protect the public health from six criteria pollutants, including carbon monoxide and particulate matter (US EPA, 2000a). As recommended by ASHRAE, pollutant levels of fresh air introduced to a building should not exceed the NAAQS levels (ASHRAE, 1989). The NAAQS were adopted by reference in the Building Officials & Code Administrators (BOCA) National Mechanical Code of 1993 (BOCA, 1993), which is now an HVAC standard included in the Massachusetts State Building Code (SBBRS, 1997). According to the NAAQS, carbon monoxide levels in outdoor air should not exceed 9 ppm in an eight-hour average (US EPA, 2000a).
Carbon monoxide should not be present in a typical, indoor environment. If it is
present, indoor carbon monoxide levels should be less than or equal to outdoor levels. Outdoor carbon monoxide concentrations were measured between 0 to 1 ppm (Table 1). Carbon monoxide levels measured in the school reflect levels measured outdoors.