6 Ways to Improve Air Quality in Classrooms

Air pollution has always been a universal concern, but one that is often swept under the rug by many schools. Children’s health is at risk due to bad air quality, especially those who live in rural regions. One example is the Southeast Asian haze, mainly caused by the burning of forests in South East Asia to clear land for agriculture. Another one is Mumbai, which was deemed the most traffic-congested city in the world. On the other hand, schools are often unaware that building materials in classrooms potentially release harmful indoor pollutants. Day-to-day products such as air fresheners, glue, and paint contain numerous air pollutants such as formaldehyde, arsenic, and benzene that can linger for many years and may cause chronic health effects in students.

Before making any changes or improvements, it is important to test the quality of your air using air quality monitors and pinpoint any sources of indoor air pollution. Identifying these sources is relatively simple. If you live in an area with excessive traffic, the source is mostly from outside. If your indoor test detects high levels of VOCs or Formaldehyde, this probably indicates a source inside the classroom. If the sources are within our control, we can then take action to eliminate these sources (such as paint, floor panels, etc.), which is more desirable than mitigation methods. However, if they are not within your control (such as traffic or neighbors burning waste), some air quality purification devices can be implemented.

How could we make schools a safer learning environment for children? Here are just some small changes that you could make to reduce pollutants in your school:

1. Use Air Purifiers

There are many types of air purifiers that remove pollutants from the air in different ways. Most purifiers contain HEPA filters, which stands for high-efficiency particulate air. It forces air to flow through a fine mesh, trapping the pollutants during the process. It is important to ensure that any purifier you purchase contains these particular filters as it sieves through the finest particles, massively improving the quality of air in your schools. These microscopic particles can enter and irritate the lungs and is especially dangerous to those suffering from asthma or allergies. The human body is relatively more resistant to larger particles such as pollen, dust, and mold as it is easily filtered by our noses. However, at larger concentrations, this could also cause major discomfort and HEPA filters can also remove them from the air.

Video: https://youtu.be/VidZMqmTgJQ

If you would like to invest in an air purifier, it is essential to understand its Clean Air Delivery Rate (CADR), which is the efficiency of the purifier. A purifier’s CADR is higher in larger purifiers, which is more suitable to larger sized rooms. Hence, large classrooms would require large purifiers such as mini-tower purifiers that have CADR above 98.

On the other hand, having a purifier does not guarantee clean air as it has to be circulated into the room regularly. Otherwise, a room filled with many people can result in a co2 build-up and there would not be enough oxygen. In order to solve this problem, we can apply some of the following ventilation systems to ensure that rooms contain breathable air.

2. Install Ventilation Systems

The simplest ventilation method is to open your doors and windows to allow the air to circulate through your rooms. However, this is dependent on the quality of your outdoor air. If it is polluted due to intensive waste burning or traffic, opening your windows would cause polluted air to flow in and let relatively clean ones flow out. If you would like to invest in proper ventilation, we would suggest the following ventilation systems that you could implement to improve air quality during these varying circumstances.

  • Positive Air Pressure system

Positive pressure ventilation systems most commonly use a fan which forces filtered dry and warm air into homes, which forces out stale and damp air as a result. This causes the pressure of indoor air to be higher than the outdoors, which results in indoor air being pushed out of homes. Moreover, we can increase the performance of this system by applying weatherstripping to close air leakage. However, if the air is not circulated through ceiling vents then this system is also costly as it requires the installation of air ducts. 

  • Negative Air Pressure System

On the other hand, negative air pressure system forces polluted air out of homes. This is highly recommended if your air quality issues originate from inside the classroom. The negative side is that once polluted air is removed, fresh air needs to be circulated into rooms. In order to make this system work optimally, it is more commonly implemented as a part of the following system.

  • Balanced Pressure Ventilation System

This ventilation system combines both positive and negative air pressure system, actively pumping and filtering fresh air into homes while pumping out stale and damp air out. This system can take full advantage of weatherstripping as it does not require any gaps in the home to push old air out, making the circulation of air dependent on the two systems. Unlike the positive air pressure system, since it allows the use of heat exchangers, your tightly sealed home would be able to conserve a lot more energy from your heating or cooling systems.

3. Replace chalkboards with whiteboards

Chalkboards are commonplace in classrooms around the world since it was invented in the early 1800s. When the whiteboard was recently invented in the late 1980s, many schools opted to use them instead as a cleaner option. Most people are vaguely aware of how suffocating it can be when chalk dust is inhaled. When used regularly by teachers and students alike, this causes the classroom to become stuffy and potentially dangerous to those who suffer from asthma or allergies.

So why do people still use the blackboard? In many developing countries, chalkboards are much more accessible and low cost compared to whiteboards. Furthermore, many may not be aware of the dangers these particles pose to children. By providing these learning resources to schools in remote areas and spreading general awareness, we could improve the health of many children and teachers by making just the smallest changes.

To learn more, the following study examines the effects of airborne chalk particles on classroom air quality that has different ventilation systems.

4. Add Weatherstripping

Weatherstripping is the process of sealing gaps within your home such as the ones on windows and the bottom of doors to prevent air from leaking. Sealing your home allows you to ensure that you have just the right amount of ventilation throughout the year. Often times, homes with air leakages are very prone to having too much (causing stuffiness) or too little air (causing drowsiness). This also prevents moisture from entering, in which the dampness can cause mold to occur.

Although weatherstripping provides numerous benefits, it can also exacerbate the air quality by trapping polluted air if it is unable to be pushed outwards. Therefore, it complements the positive air pressure system as indicated previously by controlling the flow of air.

The first step to properly weatherstripping your home is to inspect every corner and identify air leakages. Air can leak not only from door and window frames but also from cracks in the ceiling. Once you have identified and listed all the spots, you can choose what material is the best for sealing it. One such type of weatherstripping is door sweeps which are strips of nylon, plastic or vinyl attached to the bottom of a door. However, irregular cracks are best sealed using tape.  To learn more, here is a comprehensive list of the different types of weatherstripping that are made of materials and dimensions that are suited for various leakages.

5. Grow plants that remove toxins

Although it is widely known that plants actively remove carbon dioxide to produce oxygen, just a few house plants would not be able to reduce high amounts of co2. Decreasing high levels of co2 would require a lot of plants which is not a realistic expectation to have in most homes. In such cases, investing in better ventilation systems or positive air pressure systems would be much more practical.

However, a few species are known to effectively remove harmful indoor air pollutants. NASA performed a study in the late 1980s exploring what plants are the most effective in removing toxins in the air. Dracaena, Peace Lilies, and Weeping Ficus are just a few of the many household plants they have listed. For the full list, click here.

6. Remove Harmful Building Materials

If your school or home is built before 1990, it is highly likely that the building materials that were used contain and release harmful substances such as lead, formaldehyde, and asbestos. These chemicals can be difficult to detect as they do not have a distinct taste or smell but can be easily absorbed into the human body. It is crucial for homeowners to determine whether their building materials emit these substances, or which materials to use when constructing a new structure. If an existing building has these materials, professionals are able to provide services to remove these materials entirely.

In order to make initial tests for air quality, you could purchase Indoor Air Quality  (IAQ) monitors which use sensors to actively measure the particulate matter (PM), co2, temperature, humidity and other factors affecting air quality. However, if you would like to test your building materials yourself, you could purchase some home kits to test for harmful materials. For example, formaldehyde can be tested easily as its test kit involves mixing a powdery substance in water, which turns into a certain color with an indicator on the school’s formaldehyde levels. Similarly, a swab test could be performed to see if your school’s paint or wood contains lead. But testing for asbestos would require you to send samples to labs which can prove to be challenging to the untrained eye.

Nonetheless, it is highly advisable to consult an accredited professional to test your building materials as it is potentially hazardous if mishandled. Furthermore, sending samples to lab tests may take months and the results may not be reliable if they are not sampled correctly.

  • Lead

Although it is possible to remain aware of building paints for newly built schools and homes, some buildings are usually old and may contain toxic substances such as lead. If your building is over 30 years old, its paint may be lead-based. These paints can be very harmful to anyone, however children under the age of 6 are especially vulnerable to lead poisoning as their growing bodies tend to absorb more of the compounds and unknowingly consume dried paint that has been chipped off. This can result in impaired mental and physical development, causing a multitude of long-term health conditions.

If you think you may have been affected by lead poisoning, performing a blood test for your family would be great to ensure that there are no elevated levels of lead. The following booklet is a useful resource that would enable you to determine which household paints have low levels of lead and whether you should consult a professional to make your house safe again. Over many years, this can possibly lead to permanent damage to one’s nervous system, liver, and kidneys. Furthermore, such solvents are especially dangerous to people who are genetically predisposed to diseases such as Multiple Sclerosis, or to those with asthma or allergies.

  • Formaldehyde

Formaldehyde is a harmful gas that is easily absorbed into the body. It can be inhaled or absorbed through the skin and then metabolized in the body, which can cause severe irritations to the main point of contacts such as the eyes, nose, and skin. Low levels of exposure over many years can potentially lead to cancer. It can be found in cleaning agents, air fresheners, disinfectants, or stationary such as glues. Similarly, they are found in building materials such as pressed wood products, carpets, and insulation products. Formaldehyde can also come from the outdoors, coming from fuel combustions of vehicles.

To determine the level of formaldehyde in your building, you could purchase some test kits which measure the air quality and some potential sources. Tests for formaldehyde are relatively simple as it determines whether formaldehyde is present within the air instead of having to collect a sample. In order to reduce the overall amount of formaldehyde, it is best to find safer alternatives such as products that indicate that they are formaldehyde-free. This can include formaldehyde-free plywood or ones that are made using different adhesives such as soy-based resins.

  • Asbestos

Asbestos is a mineral commonly found in numerous building materials such as cement pipes, insulation, floor tiles, and adhesives. Their fibers can be easily inhaled, just like formaldehyde and can be trapped in the lungs. Those who are exposed to higher concentrations of asbestos over a long period of time are at higher risk of developing mesothelioma, which is a cancer in the lining of the lungs. Furthermore, young children are even more vulnerable to mesothelioma, increasing the chances of contracting it later in their lifetime. Asbestos is commonly found in many children’s products such as bike parts, wax crayons.

It is highly recommended to apply for an accredited asbestos inspection if you suspect that your home might have dangerous levels of it. They can provide risk assessment to already existing building materials and collect samples for testing.


The following chart summarizes the techniques that have been mentioned thus far in terms of efficiency and cost. Understanding these options would allow you to make an informed decision according to your personal circumstances in order to improve the air quality in your school.

There are multiple ways we could remedy the effects of air pollution in our everyday lives. Improving indoor air quality mainly depends on identifying the source of the pollutant and how the features of your room impact the actions you will take to mediate its effects. For example, weatherstripping is not necessary for an air-tight room but if the rooms host many people causing high levels of co2, a positive air pressure system would be greatly beneficial. However, if your building has many air leakages and you have a limited budget, then weatherstripping and using air purifiers would be favorable. Finally, whether or not you should open your windows should also depend on the quality of the outdoor air.

What must be done to increase the quality of your air is completely depending on your specific circumstances. It is important to keep these tips in mind to ensure that the health and wellbeing of your students and yourself are protected for many years to come.

by Carisa A.
Feb 7, 2020

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