Classroom Purifier or a Live Wire?

Introduction To Our Purpose

Right before the 2021-2022 school year began, Clark Magnet High School introduced the Blue-air Air Purifiers to every single classroom. These air purifiers have been proven to remove 99.99% of live airborne COVID-19 virus particles. We had noticed a UV light inside of the purifier and when discussing this with our teacher, we had been informed that UV lights are known to cause ozone emissions. We also found that shorter wavelength, higher frequency, higher energy UV radiation from the purifiers cause regular oxygen molecules to break up and then form ozone.

Hypothesis

If the ozone levels detected are above the average level of 0.1 ppm of ozone, then the Blue-air Air Filters are not safe to have in the classroom due to constant exposure to ozone which is harmful to the students and teachers.

Research Conducted

The National Institute of Occupational Safety and Health (NIOSH) states that Ozone levels of 5 ppm or more are "considered immediately dangerous to life or health". The recommended exposure limit of ozone by NIOSH is 0.1ppm ozone. They also recommend that exposure to 0.3 ppm of ozone does not exceed a time of 15 minutes  (Leusink ).

Human health effects of ozone include lung function, respiratory symptoms, and airway inflammation. Short-term effects of ozone exposure lead to problems in respiratory and cardiovascular systems. Long-term effects of ozone exposure can lead to respiratory mortality and new-onset asthma in children along with increased respiratory symptom effects in asthmatics  (Nuvolone) .

Even at LOW levels, ozone can be very hazardous to humans. Exposure to ozone can lead to premature death, asthma, bronchitis, heart attack, and other cardiopulmonary problems. Long-term exposure to ozone has been shown to increase the risk of death from respiratory illness. Such cities, for example, LA have revealed that there is a 30% increased risk of dying from lung disease  (Seyffer) .

There can be ozone found indoors as well! Ozone along with the reaction products found indoors can cause these health concerns earlier discussed. ASHRAE's Environmental Health Committee, also known as the EHC, issued an Emerging Issue Brief on Ozone and Indoor Chemistry, which started in January 2011 that "safe O3 levels would be lower than 10ppb"  (Seyffer) .

 Some tips the EHC has on minimizing emissions include:

• Removing ozone at outdoor air intakes
• Minimizing ozone emissions used indoors
• Reducing concentrations of terpenes and carbonyls using source reduction and gas-phase removal equipment
• Using high-efficiency particulate filters to remove secondary organic aerosols and ultra-fine particles that are created as byproducts of ozone reaction  (Seyffer) .

NAAQS states that the following pollutants are harmful to the human health along with the environment:

• particulate matter
• nitrogen oxides
• carbon monoxide
• sulfur dioxide
• lead
• ozone ​ (Seyffer) .

 According to NAAQS, over 100 million people today in the United States live in areas where ozone may be elevated. Not only that but "ozone may also be produced internally by any item that has an electrical field." Today, everyone is in their own chemical soup! With all of these computers, phones, etc  (Seyffer) .

There are many air filters today that state their machines can address dust particles and bacteria that may cause damage to human health. However, they do not address the potential harm the machine itself may be causing...  (Seyffer) .

Our Approach

1. December 2021: Began researching basic information regarding the project.
2. December 2021: Ordered our Forensics Detectors FD Ozone Detectors.
3. December 2021-January 2022: Researched more detailed information regarding the project.
4. January 2022: Ozone Detectors arrive.
5. January-February 2022: Work on Storymap and collect data.
6. March-April 2022: Conduct a second trial of our data collection without students present.
7. April 2022: Conduct a third trial of our data collection using a hygrometer.

Data Obtained From ArcGIS Survey123

Survey 123

 Link to Data Collected Page of Survey123 

Data was collected from a total of forty-three areas. In each area we recorded:

1. The Room Number (To assist with mapping later on)
2. The Power Status of the Filter (On-Off)
3. The Setting of the Filter (Low-Medium-High)
4. The Filter Status (Blue: Filter is Clean, Orange: Filter needs to be replaced soon, Red: Filter needs to be replaced as soon as possible)
5. Highest PPM of Ozone Detected in the Room

Highest PPM of Ozone Detected in the Room

About 1/3 of the areas were above the NIOSH recommended exposure limit. 3 of the 43 areas had highs of 0.3 ppm of ozone. It is recommended to only be exposed to this level for a maximum of 15 minutes.

Map of Clark Magnet High School

Map Data Collected

During our first trial, we noticed that breathing into the ozone detectors would cause them to go off. We immediately set up a second trial, this time without students in the classroom. In this trial, we used a different survey with the same questions as the original with minor updates, this time also asking how many people are in the room. During this time, we also reached out to the manufacturer of the ozone detectors. We received a list of the teacher's open periods from the school administration and contacted the teachers about visiting during those open periods. The data showed 0.0 ppm of ozone in every room, and a flicker of 0.1 in one of the rooms.

After some back and forth emails with the manufacturer, we found that humidity causes the ozone sensors to react. This means that the data we had previously collected was influenced by this factor.

During this experiment, we found in the first trial, with students present, that there were readings of ozone in the classrooms. In the second trial, without students present, we found minimal readings of ozone. The next step of our experiment will be to conduct a third trial using a hygrometer to measure the humidity of the classrooms.