In recent years, comparative risk studies have consistently ranked indoor air pollution (IAQ) among the top five environmental risks to public health. Good IAQ is an important component of a healthy indoor environment, and can help schools reach their primary goal of educating children. Failure to prevent or respond promptly to IAQ problems can increase long- and short-term health effects for students and staff, such as:

· Coughing;

· Eye irritation;

· Headaches;

· Allergic reactions;

· Aggravate asthma and/or other respiratory illnesses.

Nearly 1 in 13 children of school-age has asthma, which is the leading cause of school absenteeism due to chronic illness. There is substantial evidence that indoor environmental exposure to allergens (such as dust mites, pests, and molds) plays a role in triggering asthma symptoms. These allergens are common in schools. There is also evidence that exposure to diesel exhaust from school buses and other vehicles exacerbates asthma and allergies. These problems can:

· Impact student attendance, comfort, and performance;

· Reduce teacher and staff performance;

· Accelerate the deterioration and reduce the efficiency of the school’s physical plant and equipment;

· Increase potential for school closings or relocation of occupants;

· Strain relationships among school administration, parents and staff;

· Create negative publicity;

· Impact community trust; and

· Create liability problems.

Due to varying sensitivities among school occupants, IAQ problems may affect a group of people or just one individual and may affect each person in different ways. Individuals that may be particularly susceptible to effects of indoor air contaminants include, but are not limited to, people with:

· Asthma, allergies, or chemical sensitivities;

· Respiratory diseases;

· Suppressed immune systems (due to radiation, chemotherapy, or disease).

Certain groups of people may be particularly vulnerable to exposures of certain pollutants or pollutant mixtures. For example, people with heart disease may be more adversely affected by exposure to carbon monoxide than healthy individuals. People exposed to significant levels of nitrogen dioxide are also at higher risk for respiratory infections.

In addition, the developing bodies of children might be more susceptible to environmental exposures than those of adults. Children breathe more air, eat more food and drink more liquid in proportion to their body weight than adults. Therefore, air quality in schools is of particular concern. Proper maintenance of indoor air is more than a "quality" issue; it encompasses safety and stewardship of your investment in students, staff and facilities.

The major indoor air pollutants include particulate matter (PM), microbiological agents (e.g. bacteria, fungi), carbon dioxide (CO2), volatile organic compounds (VOCs) and other emerging pollutants namely semi-volatile organic compound (SVOC) groups, such as phthalates, flame retardants (brominated and organophosphorus), polycyclic aromatic hydrocarbons (PAHs), pesticides and per- and polyfluorinated substances (PFAS).

“An endocrine disruptor is an exogenous substance or mixture that alters function(s) of the endocrine system and consequently causes adverse health effects in an intact organism, or its progeny, or (sub)populations.” The International Programme on Chemical Safety (IPCP) in 2012.

We are exposed to a large number of different combinations of pollutants, namely chemical agents, via air, water, food, consumer products, materials and goods. In addition, pharmaceuticals, drugs, tobacco and occupational exposures add to the number and potential combinations of chemical mixtures. A large body of evidence has accumulated showing that exposure to endocrine disrupting chemicals (EDCs) may have be associated with the most common chronic diseases and disorders of the western world, such as metabolic syndrome and diabetes type II, neurodevelopment disorders, and decreased fertility. These diseases and disorders are among the most cost-intensive we see in society today. Hence, there is an urgent need for better risk management. However, the current health risk assessment paradigm is largely based on considering the exposure to single pollutants. Nevertheless, the combined exposure to multiple pollutants (microbiological agents, chemical or physical parameters) raises serious concerns about the impacts on health and environment. The scientific evidence is increasing about co-exposure effects, pointing out that a neglect of combined effects can lead to underestimation of risk.