“80% of success is showing up” – Woody Allen
There are many variants on the theme quoted above, but they all allude to the same thing: a person can’t progress if they are not there. Every year, millions of days of school attendance are lost for a host of reasons. In a study in North Carolina in 2011, parents reported that about 60% of absences were for illnesses and injury. Of that 60%, over a third (22%,), were for respiratory illnesses such as asthma and allergies. Fever was a distant second at 9%, followed by GI/GU (6%) and others less than 3% each.1
These statistics are not atypical. According to the National Health Statistics Report2, in 2008, school students lost 10 million school days due to asthma alone. One of the leading causes of asthma attacks is poor indoor air quality within schools. With all the people, paper, equipment, etc., which come and go within the walls of a school, many things that can trigger asthma attacks are continually being introduced into the air. Dealing with this is a primary, though possibly underappreciated, function of the HVAC system.
The primary role of the HVAC system is keeping the building warm in the winter and cool in the summer in order to provide optimum comfort for the buildings’ occupants. A few decades ago, it was common practice to open the windows in the spring, summer and fall rather than have air conditioning. Fine for cooling off the building, but not ideal for folks with hay fever or asthma. Nor is this desirable in modern urban settings near roads full of cars, trucks, school busses and industries. By providing air conditioning, modern schools can have much more control of the indoor air quality, not only the temperature and humidity, but also the cleanliness.
Three of the most effective strategies for improving the air quality are ventilation, filtration, and disinfection. To remove carbon dioxide from being inhaled, some air from the outdoors is brought in and some indoor air exhausted. But that outdoor air has pollen, dust and pollution and needs to be cleaned. Within the building are other sources of contamination as well. To remove these, filters are used that allow the small molecules of air to pass through while preventing the larger pieces of pollen, dust, etc. from passing. Also, there are viruses and other microscopic organisms in the air, which people bring in schools each day. To remove or deactivate such organisms, ultra-violet lights or HEPA filters can be used.
Naturally, all these strategies add complexity to the system, use energy to operate, and need to be maintained to function effectively. But compared to the cost of absenteeism to the student, to the schools and ultimately to society at large, installing, operating and maintaining an effective air quality system is a very good investment.
 Kerr, Price, Kotch, Willis, Fisher and Silva, “Does Contact by a Family Nurse Practitioner Decrease Early School Absence?” The Journal of School Nursing, 2011
 Akinbami, Moorman, Liu, “Asthma Prevalence, Health Care Use, and Mortality; United States, 2005-2009” National Health Statistics Reports, January 12, 2011.