Poor indoor air quality within schools has long been identified as one of the leading causes of student and teacher illnesses. Ever since the 1920s, public schools have been aware of the importance of ventilation and humidity control. In 1923, the New York State Commission on Ventilation found that pupils in fan-ventilated rooms suffered 70 percent more upper respiratory illnesses compared to students in window-ventilated classrooms. With crowding an ongoing issue in public schools, temporary humidity control and adequate ventilation are vital to keeping infectious diseases and allergens at bay.
Humidity-Related Health Concerns
The ideal relative humidity range is between 40 and 70 percent, according to the January 2014 studies in the International Journal of Engineering Science Invention. Within the last century, scientists discovered that both low and high relative humidity levels lead to a handful of health concerns.
Effects of Low Relative Humidity Levels
- Discomfort: Low humidity levels may dry mucous membranes, eyes and throats. In healthy students, the dry conditions may cause discomfort, which may distract them from classroom activities. In those who have a cold, rhinitis or bronchial constrictions, low humidity levels may exacerbate symptoms.
- Spread of illnesses: Overly dry conditions may increase the incidences of some illnesses, particularly in children. Some bacteria, viruses, and pathogens thrive in environments with relative low humidity levels, especially when proper ventilation and temporary humidity control solutions lack. Examples include:
- Rhinovirus
- Human rotavirus
- Influenza
- Measles
- Herpesvirus
- Varicellae
- Rubella
- Mycoplasma pneumonia
- Streptococcus
Effects of High Relative Humidity Levels
- Mold growth: The main cause of mold growth is excess moisture. Most molds grow when relative humidity levels are 60 percent or higher. Certain molds are not toxic themselves, but may produce mycotoxins. Exposure to some types of molds may reduce mental clarity, cause illnesses or allergic reactions, or trigger asthma symptoms.
- Allergens: A lack of ventilation and temporary humidity control exposes students and teachers to allergens like mold, pollen and dust.
- Asthma: Asthma is a lung disease that causes airway inflammation and bronchospasms. In children, this illness is the leading cause of absenteeism in school. While moderate levels of humidity are beneficial to those with asthma, high humidity levels may trigger asthma symptoms if a student is sensitive to mold or dust. High humidity levels and molds may also lead to new-onset asthma. Asthma is one of the leading causes of student absenteeism, significantly reducing time in classroom for many students each year.
- Spread of illnesses: Like extremely low humidity levels, environments with high humidity levels promote the growth and spread of pathogens, including:
- Staphylococcus albus (staph infection)
- Serratia marcescens
- Adenoviruses
- Coxsackie viruses
- Fifth disease
- Salmonella typhi
- Cholera
The humidity inside a school is one of the most vital factors when determining the quality of indoor air. Polygon offers temporary humidity control solutions throughout the school year, as well as those for campus construction projects. Our solutions complement and reduce the strain on HVAC systems while promoting the health and performance of students and faculty. Contact Polygon to learn more about its energy- and cost-efficient solutions.
[Sources: Ventilation | Report of the New York State Commission on Ventilation; Effects of Indoor Humidity on Human Health]
[Photo from Lucella Ribiero via CC License 2.0]
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