Promoting healthy school environments: a step-by-step framework to improve indoor air quality in Tangipahoa Parish, Louisiana.

Author:Massawe, Ephraim
Position:ADVANCEMENT OF THE SCIENCE
 
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Introduction

Most people spend more than 90% of their time inside of their homes and in various microenvironments, including automobiles, offices, grocery stores, malls, hospitals, and classrooms (Burge, Hoyer, Gunderson, & Bobenhausen, 2003; U.S. Environmental Protection Agency [U.S. EPA], 2011a). The amount of the time an average person spends indoors has drastically increased over the years partly because more people have shifted from rural lifestyles to more urban lifestyles. Urban lifestyles involve work, learning, and conducting activities that predominantly take place in indoor environments. For the infirm and school children, the percentage of the time spent indoors is even greater.

The quality of the air in most indoor microenvironments might be as poor, and in some cases, poorer than the outdoor air quality (U.S. EPA, 2009). Estimates from the U.S. Environmental Protection Agency (U.S. EPA) and numerous literature sources put the quality of indoor air at between 2 and 10 times poorer than the outdoor air quality (Axelrad, 2006; California Air Resources Board [CARB], 2005; Payne-Sturges, Burke, Breysse, Diener-West, & Buckley, 2004; Sheldon et al., 1994; U.S. EPA, 2009). In some cases, the levels of indoor air pollutants may reach as high as 100 times higher or more than the outdoor pollutant levels (U.S. EPA, 2011a).

As a consequence of poor indoor air quality (IAQ) in schools, students, teachers, and staff who occupy school buildings can potentially be exposed to various pollutants, which can lead to significant negative health outcomes.

The identification, evaluation, and control of indoor air pollutants can be difficult, particularly because some pollutants or sources of environmental triggers of asthma may not be obvious. Since the impact of the IAQ problem can be significant due to the large number of people who can be affected, it is paramount to provide a systematic approach to address a growing problem in schools, homes, and other indoor environments where children, the elderly, and the infirm spend most of their time. About one in every five Americans spends a large amount of time in a school environment, either indoors or outdoors (U.S. General Accounting Office, 1995).

The purpose of this article is to present background information about schools in Tangipahoa Parish, Louisiana, as work environments as well as justification for a new approach to improve and sustain IAQ in schools in the area that is conducive to productive learning. The proposed approach is a step-by-step methodology or framework modeled and adapted from the U.S. EPA's Tools for School (TfS) kit, an action-based protocol that embraces a team-approach to solving IAQ problems. The U.S. EPA TfS kit, which has been used successfully in various schools across the country, requires fewer resources in terms of funds and human skills, which semirural schools may be able to provide.

Potential Sources of Poor IAQ

Poor IAQ, particularly in work environments such as schools, is one of the many factors that provides an uncomfortable and unhealthy working or learning environment to individuals. Many times poor IAQ is attributed to work practices and processes taking place indoors. Other factors leading to poor IAQ are relative humidity, room temperatures that can be too high or too low, inadequate air movement, and the radiant temperature.

Work Practices and Processes In and Outside the School Environment

Certain consumer products that are frequently used inside school buildings and in the immediate vicinity outside of the school buildings can be a potential source of pollutant emissions and may subsequently cause poor IAQ. Some common sources of pollutants include cleaning products, air fresheners, art supplies, and laboratory chemicals. Airborne pollutants can be found in janitorial closets that serve as storage for cleaning products. Heating and cooling systems, idling school bus fleets, transportation vehicles, and environmental tobacco smoke can also release a significant amount of indoor air pollutants. (American Academy of Pediatrics Committee on Environmental Health, 1993, 1997; U.S. EPA, 1992a).

Additional factors related to work practices and processes that may occur in and around the school environments are construction, demolition, and renovation (New Jersey Work Environment Council, 2002). Because these factors can lead to poor IAQ due to their potential for creating airborne pollutants they are commonly known sources of the environmental triggers of respiratory diseases, including asthma. The most common causes of poor IAQ that have significant health and safety impacts include ozone from office machines; formaldehyde and aldehydes from paints, treated wood, or fabric; polycyclic aromatic hydrocarbons from cooking, wood burning, and other combustion; solvents such as benzene, xylene, and toluene; asbestos from building materials such as plumbing and roofing; and nitrogen dioxide, carbon monoxide, and carbon dioxide from combustible products (CARB, 2005; U.S. EPA, 1992; U.S. EPA, 2009). The impacts of pollutants such as combustibles, biological contaminants, volatile organic compounds (VOCs), formaldehyde, soil gases (radon, sewer gas, VOCs, methane), pesticides, particles, and fibers can be both systemic and local health effects that can lead to multiple hospital visits and financial burdens.

Factors Affecting IAQ

The relative humidity, indoor air temperature, air movement, and radiant temperature may lead to perceived poor IAQ, and these four factors often characterize the degree of comfort to the inhabitants of indoor environments. Relative humidity in particular is associated with the moisture content from plants, perspiration, and evapotranspiration of plants.

Relative humidity, which measures the amount of water vapor in the ambient air, for example, depends on the temperature of air. Other significant sources of relative humidity include wet carpets, woods, floors, and water intrusion from the walls. The higher the temperature, typically, the higher the ability of the air to absorb more water, and vice versa. The air temperature may affect comfort and an indoor environment may seem stuffy. This perception of poor IAQ may cause fatigue in classrooms and as a result leads to poor academic performance.

Air movement is a result of air flow from low pressure to high pressure environments typically caused by a fan, furnaces, natural convection, air leakages, and movement of residents in the indoor air environment. An average American breathes about 3,400 gallons of air each day.

The American Society of Heating, Refrigeration, and Air-Conditioning Engineers' (ASHRAE's) definition of an acceptable IAQ or "safe air" is air with no known airborne contaminants or other conditions whereby more than 80% of the exposed population does not suffer significant dissatisfaction with the quality of the air. Poor IAQ typically occurs when toxic substances and other airborne pollutants are emitted into buildings or when a lack of adequate ventilation exists during winter or summer months. This is very common for buildings constructed in the 1970s following the first energy crisis. At that time during the oil crisis, most building codes across the U.S. emphasized energy efficiency or reduced energy consumption through air tightness, and as result, most buildings in schools have relatively poor ventilation systems.

ASHRAE Standard number 62-1999 recommends a minimum ventilation rate of about 8 L per second, an equivalent of about 15 cubic feet per minute per person for a typical classroom.

Previous research was conducted by the University of Tulsa's IAQ program using carbon dioxide measurements as surrogates of ventilation performance in 5th grade classrooms of 51 schools (Mendell & Heath, 2005; Shaughnessy, 2008). Most schools in that study had inadequate ventilation system rates less than the minimum recommended values. A strong association occurred between the classroom ventilation rates and student performance when the results were compared with the standardized scores and the profile of the 5th graders in those classrooms. A similar study was conducted in about the same number of schools and resulted in similar conclusions, i.e., a better ventilation rate was linked to higher performance scores (Shaughnessy, 2008).

The main recommendation from these observations is to consider basic interventions in the form of IAQ improvement programs and focus on the ventilation systems in particular. These actions can improve test scores by reducing exposures and health risks...

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