In recent years, increasing attention has been paid to indoor air quality in schools. About 57 million students, teachers and staff attend US elementary and high schools. Types of school buildings used in the USA are quite variable and range from new buildings, which often have poor ventilation, to buildings more than one hundred years old, which may have problems with dust, lead paint, and mold and moisture damage.
A major impetus for school indoor air quality concerns is the high prevalence of asthma in children and adolescents. In 2005, about 10% of US elementary and high school students had asthma. Among some schools with children of predominantly African or Puerto Rican descent, asthma rates as high as 30% have been reported. In 2004, there were 750,000 childhood emergency room visits for asthma in the US. Asthma is the biggest medical cause of school absences and accounted for 12.8 million days of missed school annually for children under age 18 years in 2004. (Data for this paragraph from Akinbami L; Centers for Disease Control, National Center for Health Statistics. The state of childhood asthma, US, 1980–2005. Adv Data. 2006; 381:1–24.)
Mold and moisture problems are a major problem in many schools. In the past decade, several Illinois schools have had to be closed due to mold problems. A study of 60 schools in southeastern Texas reported that 86% of all dust samples had high mold levels (over 10,000 spores per gram) (January 2002- Journal of School Health). In the past decade, several US schools have been heavily infested with Stachybotrys, a mold that produces large quantities of mycotoxins which can damage the immune and neurological systems. Other common molds linked to school mold problems and childhood asthma include Cladosporium, Aspergillus (especially Aspergillus versicolor) and Penicillium.
A number of studies have reported that asthma and wheezing rates are significantly higher in schools with mold and water problems than schools with no mold and water problems (Acta Paedetrica December 1999). A Finnish study reported that childhood rates of asthma, bronchitis and the common cold were significantly higher in a water damaged school as compared to a dry school. One year later, following extensive remediation and clean-up at the school, rates of respiratory problems fell to the level experienced at the dry school. (Archives of Environmental Health, Nov/Dec 2000).
Mold growth in schools is best controlled by preventing, or rapidly fixing, water damage. All flooding and water leaks should be cleaned and fixed within 24 hours or serious mold and bacteria growth can occur. Mold covered non porous surfaces like floors, walls and ceilings can be cleaned with dilute bleach or quaternary ammonium compounds. Water damaged porous materials, like carpets and furniture, may have to be discarded after they became wet. Air conditioners or dehumidifiers should be used in wet weather to reduce school humidity and thus reduce growth of mold and bacteria.
Schools frequently contain significant amounts of allergens from dust mites, cats, cockroaches and mice/rats. Significant levels of these allergens are associated with increased asthma rates. Schools often have significant levels of cat allergens, even when no cats are present in the school. The cat allergens travel to the school from students and teachers who live with home cats. High levels of pigeon allergens were collected inside a pigeon infested Chicago High School (Luke Curtis- Allergy- July 2002). A study of 80 Texas schools reported that dust allergen levels exceeded asthma threshold limits in 20% of samples for dust mite allergens and 10% of samples for cockroach allergens (January 2002- Journal of School Health). Keeping schools clean, dry and free from food crumbs are vital for controlling levels of allergens from animals. Use of spikes, scarecrows, netting and non-toxic repellants, like methyl anthranilate, may be needed to control pigeons in schools.
Poor ventilation is a common concern in schools, especially in newer buildings which may not have windows which open. Inadequate amounts of outdoor air flow into buildings can increase airborne levels of carbon dioxide, volatile organic compounds and other pollutants. Many studies have reported the low levels of outdoor air ventilation to be associated with asthma, skin irritation, headaches and chronic fatigue. A study of 400 Danish children reported that low levels of outdoor air ventilation in homes (less than 0.5 air change per hour) were associated with significantly higher levels of asthma, nasal congestion and skin irritation (Indoor Air- August 2005).
Whenever possible, school windows should be kept open in mild weather to allow for adequate outdoor air flow. Schools with forced air systems should supply at least 2 outdoor air changes per hour.
Many school buildings are regularly sprayed for pesticides. While pesticides can kill cockroaches and other insects, they can trigger asthma and neurological problems in children. Pesticide exposure in schools has been linked to significantly higher rates of childhood asthma (European Respiratory Journal September 2003). A study published in January 2008 Journal of Pediatric Psychology reported that exposure to organophosphate pesticides significantly reduced children's memory, attention, vision, and conceptional abilities.
Cleanliness and water control can do much to control cockroaches and other insect pests. If pesticides are needed to control insects, the use of less toxic controls, such as boric acid or pesticide traps, should be used instead of spraying the entire school.
Vapors from “volatile organic chemicals” such as paints, solvents, cleaners and perfumes/fragrances found in schools can also worsen asthma and other child health problems. Adequate outdoor ventilation can be helpful to dilute many of these volatile organic compounds. Whenever possible, painting, cleaning and use of solvents should be performed during weekends and vacations when children are not present in school. Students and teachers should avoid wearing large amounts of perfume and artificial fragrance which can worsen asthma in children.
Malfunctioning heating systems can produce large amounts of carbon monoxide which is odorless and can cause headaches, fatigue, and flu like symptoms. High concentrations of carbon monoxide can cause death. While heating malfunctions are rare in schools, school carbon monoxide levels should be monitored during the heating season to made certain that the heating equipment is working properly.
Lead based paint in schools was a major problem in schools built before the 1970’s when use of lead based paint was banned. Small quantities of lead can have many toxic effects to the nervous system- especially in growing children. Low level exposures to lead in the blood (as low as 5 or 10 micrograms per deciliter of blood- or 50 parts per billion) can significantly lower IQ levels and significantly increase the risk of violent behavior, depression and suicide. A study published in the October 2008 Environmental Health reported that 1.6% of US children have high blood lead levels exceeding the limit of 10 micrograms per deciliter of blood.
Regular lead testing of the schools built before the 1970’s should be performed to determine if any lead based paint returns. Children living in or attending school in older buildings should have at least one blood lead test to determine if they are contaminated with lead. If lead levels exceed 5 micrograms per deciliter of blood- steps should be taken to reduce lead levels in children. Various steps can be taken to remove old lead paint and/or reduce the amounts of paint dust and chips produced in an older home. A nutritious diet with adequate magnesium, calcium and iron can also reduce the amount of lead absorbed by children.
What can family members do to improve school indoor air quality? Parents frequently express concerns about school indoor quality during teacher- parent conferences and during group meetings, like the PTA. Many schools have indoor air quality committees comprised of teachers, school administrators and parents. Many family members discuss their school indoor air quality concerns with public and school officials and in newspaper letters-to-the-editor.
Families with asthmatic children should also communicate with teachers, school nurses and educational administrators about the need for an asthma control plan. Asthmatic children on medication should be taught the proper techniques for administering inhaled asthma drugs. In the past, some schools required asthmatic children to have asthma inhalers administered by school nurses. This requirement for school nurse administered asthma inhalers often caused harmful delays in getting asthma treatment. Most schools will now allow asthmatic children and teenagers to self-administer asthma inhalers, if the student has been trained in proper inhaler techniques. Today, childhood use of asthma inhalers is so common that just about every elementary student knows what an asthma inhaler looks like. Sometimes asthmatic school children are provided with portable air filters to reduce their exposure to indoor pollution.
Readers wishing to obtain electronic copies of research papers related to this article are welcome to contact me at LukeTCurtis@aol.com.