Air Cleaning in Practice: Improving IAQ and Saving Energy in Schools, Part 1 of 2

Many studies have reported the benefits of using “fresh air” with regards to students’ health and performance in K-12 classrooms. The primary use of this “fresh,” or outdoor, air has been to keep the levels of carbon dioxide (CO2), a byproduct of human respiration, below recommended and, in some instances required, maximum levels. Guidelines recommending a maximum of 1,000-1,200 parts-per-million (ppm) inside of classrooms are most common and outdoor air is used to “dilute” CO2 to near ambient levels of 350-400 ppm.

It is a given that CO2 levels within a defined space (e.g. classrooms) will increase with the number of students and their activity levels. Recent studies have reported a decrease in some student capabilities at elevated CO2 concentrations with some now regarding CO2 as an indoor air pollutant. However, these same studies have found that many classrooms are “under-ventilated” based on the peak CO2 levels obtained during the school day and there has been a consistent call for increasing the amount of outdoor air being used for ventilation in school buildings.


This has been met with considerable resistance with two primary arguments to keep outside air ventilation rates where they are. These are:

  1. Significant increases energy costs for the operation and maintenance of heating, ventilating, and air-conditioning (HVAC) systems due to increased amounts of outdoor air that have to be conditioned in order to achieve and maintain acceptable indoor temperature and humidity.
  2. The inability of older HVAC systems and equipment to handle the additional air conditioning loads and maintain a comfortable indoor environment.

A third, and for many the most important reason for not introducing higher rates of outdoor ventilation air is that this air is oftentimes neither “fresh” nor clean – especially in major urban centers or where there is significant industrial activity. The American Lung Association’s latest State of the Air-2016 Report (Source: concludes the following: 

  • More than half of the people in the United States (52.1%) live in counties with unhealthy levels of either ozone or particle pollution. This is an increase from the 2015 report.
  • More than 22.8 million people (7.1%) in the United States live in 20 counties with unhealthful levels of all pollutants measured in the report.
  • Twenty-two of the 25 most ozone-polluted cities in the 2016 report – including Los Angeles, New York City, and Chicago – had more high ozone days on average when compared to the 2014 report.
  • Los Angeles remains the metropolitan area with the worst ozone pollution, as it has for all but one of the 16 State of the Air reports.

The United States Environmental Protection Agency (EPA) states that over one hundred and sixty million people are living in US counties where the concentrations of one or more of the criteria air pollutants exceed the primary (health-based) National Ambient Air Quality Standards (NAAQS). Further, the EPA has lowered the primary level for fine particulate matter (PM2.5) and updated and strengthened the national ozone standard, officially recognizing that these contaminants are unhealthy to breathe at lower levels than previously thought.

The National-Scale Air Toxic Assessment (NATA) assesses ambient levels, inhalation exposures, and health risks associated with 187 toxic air pollutants and diesel particulate matter (DPM). NATA estimates risks from breathing air toxics that are emitted from large and small industrial sources, and from mobile sources such as cars, trucks and construction equipment. NATA found more than 48,000 regions in the US with a respiratory hazard.

The Center for Effective Government studied the EPA’s Risk Management Program and found that one in 10 children attend schools near chemical plants and that these chemicals can be dangerous to the public if they are spilled, released into the air, or are involved in an explosion. Their data shows that nearly 4.6 million children in 10,000 schools are located within a mile of a chemical facility that could be the source of highly toxic gases and more than 134 million Americans live in the danger zones around 3,433 industrial facilities in several common industries that store or use highly hazardous chemicals. The USA Today and the EPA Project: Assessing Outdoor Air Near Schools have found that at thousands of school locations, the outdoor air could be far more toxic than the air in the neighborhoods where the students lived. At 16,500 schools, the air outside appeared at least twice as toxic as the air at a typical location within the school district.

University of Cincinnati researchers have found that more than 30 percent of American public schools are within a quarter mile of major highways that consistently serve as main truck and traffic routes. Research has shown that proximity to major highways – and thus environmental pollutants, such as aerosolized DPM – can leave school-age children more susceptible to respiratory diseases later in life. One example of the closeness of schools and communities is the Twin Ports region of Los Angeles and Long Beach in California.

The schools are located near to ships, trucks and other diesel engine powered equipment, major highways, rail yards, refineries, and other chemical plants. In addition, wood smoke from nearby wildfires, smog from Los Angeles, agriculture generated dusts, and other pollution sources such as dust and motor vehicle pollutants carried on the jet stream across the Pacific Ocean from China add to the outdoor air contaminant list. Many scientists say children living in cities are at an increased risk of developing brain inflammation and neurodegenerative changes, including Alzheimer’s or Parkinson’s disease due to air pollution.

Beijing, China CBD Cityscape

Professor Lilian Calderon-Garciduenas from the University of Montana has found that air pollution is harming brains of urban kids. Her studies have found when airborne particulate matter with its adsorbed chemicals and components such as metals are inhaled or swallowed, they pass through damaged barriers, including respiratory, gastrointestinal and the blood-brain barriers and can result in long-lasting harmful effects. The results found that the children living in Mexico City had significantly higher serum and cerebrospinal fluid levels of autoantibodies against key tight-junction and neural proteins, as well as combustion-related metals. We asked “why a clinically healthy kid is making autoantibodies against their own brain components,” she said. “That is indicative of damage to barriers that keep antigens and neurotoxins away from the brain. Brain autoantibodies are one of the features in the brains of people who have neuroinflammatory diseases like multiple sclerosis,” said Calderon-Garciduenas.

She notes that once there is a breakdown in the blood-brain barrier, not only will particulate matter and chemical pollutants enter the body but it also opens the door to harmful neurotoxins, bacteria and viruses. “The barriers are there for a reason. They are there to protect you, but once they are broken the expected results are not good,” Calderon-Garciduenas said. While the study focused on children living in Mexico City, others living in cities where there are worrying levels of air pollution such as Los Angeles, Philadelphia-Wilmington, New York City, Salt Lake City, and Chicago also face major health risks.

Join us for our next post where we share how Purafil can help provide “fresh air” to our children.

In the meantime, visit to learn more about Purafil and about their products or contact us to see how Purafil could help your environment.

By Chris Muller, Director of Technical Services at Purafil  – Filtration Group 


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