A high school chemistry teacher noticed she was having symptoms—including a sore throat, headache and coughing—whenever she was working in her laboratory instructional space and related areas (preparation and chemical storeroom). She also detected characteristic odors during labs involving fumes, gases, and/or particulates. Her students also were complaining about sharp odors and similar symptoms.  

Feeling concerned, she contacted the school principal, sharing her and the students’ symptoms. The principal replied that she worked in a chemistry lab, and those labs were supposed to smell! Unhappy with that response, the teacher decided to contact the school’s chemical hygiene officer (CHO). The CHO determined that something definitively was wrong and contacted the head of the Facilities Department.  

After checking the computer sensors on the HVAC system, the Director of Facilities said there was no issue with the ventilation, based on the sensor feedback. Still concerned, the CHO insisted that the Director of Facilities send a maintainer up to the building roof to inspect the HVAC system unit. A day later, the Director told the CHO it was a good thing the inspection was performed. A motor operating the pulley in the HVAC system was working, but the belt had broken off. This prevented air in the instructional space and related areas from being properly ventilated.  

This is only one example of an indoor air quality issue that could be found in science laboratory instructional spaces and related areas. According to the Environmental Protection Agency (EPA), “Indoor Air Quality (IAQ) refers to the air quality within and around buildings and structures, especially as it relates to the health and comfort of building occupants. Understanding and controlling common pollutants indoors can help reduce employee and student risk of indoor health concerns.” A number of potential IAQ issues can exist in the school workplaces, especially in areas like science, technology education, art studios, and STEM/STEAM instructional spaces and their related areas. What are these potential IAQ issues and how can they be addressed?  

Indoor Air Quality and HVAC Systems 
IAQ issues are usually caused by biological, chemical, and/or physical pollution sources that can release gases and/or particles that collect in a school’s indoor environments. The source of these pollutants can come from outside, inside, or within the mechanical system of the school. Once a pollutant is in the school, whether or not an air pollutant creates an IAQ problem is often impacted by the efficacy of the HVAC units/system. HVAC systems improve indoor air quality by providing ventilation (providing or introducing fresh air), removing contaminants/particulate from the air (through filtration), and regulating thermal comfort (temperature and humidity levels) within a school.

Laboratory instructional spaces and related areas depend on 100% fresh air supply and total removal as the return out of the building. Inadequate ventilation, as noted in the introductory chemistry lab scenario, can increase indoor pollutant levels by either not bringing in enough outdoor fresh air to dilute emissions from indoor sources and/or by not carrying indoor air pollutants directly out of the facility. Elevated temperature and humidity levels can also contribute to an environment that is more conducive for the growth of certain biological pollutants.

A number of potential IAQ pollutants and even more potential sources inside and outside of a school can exist. The complete elimination of these sources is not usually an option, so proper upkeep and maintenance are often critical in controlling them. Uncontrolled pollutants and pollutant sources can potentially lead to diminished IAQ resulting in harmful effects on human health.

The following are some typical examples of potential IAQ pollution sources.  

A. Biological. The growth of bacteria, fungi, and viruses are fostered by excess levels of moisture and damp indoor environments. These biologicals can potentially lead to a multitude of respiratory symptoms and health issues. Additional examples of biological pollutants that can be found in schools and biology laboratory instructional spaces include animal dander, pest infestation, dust mites, Legionella, microbial contaminants, and pollen. Limiting water/moisture intrusion and proper upkeep and maintenance of building HVAC systems (to maintain proper temperatures and humidity levels) are important for limiting biological growth.

B. Chemical. Chemical pollutants are typically in the form of gases and vapors. Chemical pollutants typically originate in the following categories:

1. Chemicals used in the building (like cleaning supplies, paints, stains, polishes, etc.) and accidental spills/releases of those same chemicals; 
2. Chemicals used in science (flammables, toxins, heavy metals, etc.), technology/engineering education (paints, oils, etc.), and art (paints, silica in clay dust, etc.) instructional spaces and related areas for hands-on activities;
3. Chemicals from outside of the building that are pulled into the HVAC system (or through windows and other openings), such as pesticides, school bus diesel/motor vehicle exhaust (carbon monoxide, NOx, PM 2.5), ozone, etc.;  
4. Chemicals such as volatile organic compounds (VOCs) released from various materials and products;
5. Chemicals used during construction activities;
6. Chemical gases emitted during improper venting of combustion products (CO); and 
7. Chemical gases from soils seeping into the building, such as radon, pesticides, and leakage from underground storage tanks.

C. Physicals. Physical particles can be anything solid or liquid suspended in the air. Some examples of common physical particle sources found in schools are these.

1. Housekeeping, maintenance, or construction activities creating dust or debris;
2. Ventilation system/ductwork—dust or debris;
3. Power tools used in art, technology education labs, and STEM/STEAM labs, producing wood and metal dust; 
4. Other physical components may include elevated humidity and temperature levels, ventilation air exchange rate, etc.; and
5. Damaged building materials that are asbestos-containing or coated with lead-containing paint.

Given that a number of possible IAQ pollutants can exist in the instructional space and related areas, the Occupational Safety and Health Administration (OSHA) recommends the following “Three Lines of Defense” or “Hierarchy of Controls” approach involving specific actions to address IAQ issues in the work space and to eliminate worker exposure.

A. First line of defense. This is the most effective approach, involving the elimination and engineering of the hazards out of the instructional space. This would include removal, substitution, and enclosure of potential pollutant sources. In cases where the hazard cannot be eliminated, the exposure must be controlled. 
B. Second line of defense. This involves use of administrative controls, including safety protocols; for example, limiting the exposure through work schedules, training, chemical hygiene plans, and housekeeping. 
C. Third line of defense. This involves use of personal protective equipment (PPE):  meaning the use of respirators, gloves, protective clothing, eyewear, and footwear.

See OSHA Chemical Hazards and Toxic Substances and Hierarchy of Controls.
 

Building indoor air quality takes time and persistence in many cases. In the EPA booklet Building Air Quality, the following actions are suggested for building owners and facility managers to help rectify and secure indoor air quality (see https://www.epa.gov/sites/default/files/2014-08/documents/iaq.pdf ).

1. Initial Walkthrough. An initial walkthrough of the functional area/space with the potential IAQ problem provides information about four basic factors influencing indoor air quality (occupants, HVAC system, pollutant pathways, and contaminant sources).  In some instances, an initial walkthrough may provide sufficient information to identify and resolve the problem. If not resolved, it will direct further investigation. 
2. Developing and Testing Hypotheses. As you develop an understanding of how the building functions, where pollutant sources are located, and how pollutants move within the building, you may think of many “hypotheses,” potential explanations of the IAQ complaint. Building occupants and operating staff are often a good source of ideas about the causes of the problem. Hypothesis development helps to identify and focus on possibilities. 
3. Collecting Additional Information. If the hypothesis does not seem to be a good predictor of what’s happening in the building, additional information about the occupants, HVAC system, pollutant pathways, or contaminant sources may be needed. Outside assistance may be needed if repeated efforts fail to produce a successful hypothesis or if the information required calls for instruments and procedures that are not available in-house.
4. Results of the Investigation. Analysis of the information collected during your IAQ investigation could produce any of the following results. 

a. The apparent cause(s) of the complaint(s) are identified. Remedial action and follow-up evaluation will confirm whether the hypothesis is correct. 

b. Other IAQ problems are identified that are unrelated to the original complaints. These problems (e.g., HVAC malfunctions, strong pollutant sources) should be corrected when appropriate. 

c. A better understanding of potential IAQ problems is needed to develop a plan for corrective action. It may be necessary to collect more detailed information and/or to expand the scope of the investigation to include building areas that were previously overlooked. Outside assistance may be needed. 

d. The cause of the original complaint can’t be identified. A thorough investigation has found no deficiencies in HVAC design or operation or in the control of pollutant sources, and there have been no further complaints. In the absence of new complaints, the original complaint may have been due to a single, unrepeated event or to causes not directly related to IAQ. 

5. Using Outside Assistance. Some indoor air quality problems may be difficult or impossible for in-house investigators to resolve. Special skills or instruments may be needed. Other factors can also be important, such as the benefit of having an impartial outside opinion or the need to reduce potential liability from a serious IAQ problem. When you bring in an environmental consulting firm to investigate a potential IAQ problem, you are getting a professional who has years of experience dealing with IAQ issues at schools and a variety of other types of buildings as well.  

Professional IAQ consultants are investigators by trade and have specialized equipment available to them for examining a variety of concerns. For example, they can use equipment to screen for and take direct real-time measurement of IAQ pollutants (carbon monoxide, VOCs, etc.) and/or factors affecting the levels of IAQ pollutants and occupant comfort in an area (Temperature, Relative Humidity, etc.) and collect air samples targeting a specific pollutant (mold/fungi, radon, etc.) for analysis at a laboratory. The information gathered from various types of testing performed, combined with their own experienced observations and with the observations from the staff/facilities, can often bring clarity and resolution to an IAQ concern.

Indoor air quality is critical for employees and students in school settings, especially in laboratory instructional spaces and related areas where there tends to be additional potential sources for biological, chemical, and physical contaminants just by the nature of the curricular activities. Remember that the students come and go from the laboratory during the day, while the teacher stays in the laboratory for the whole day! If a teacher suspects an indoor air quality problem, they need to be persistent in attempting to get the administration and facilities involved in investigating the issue further starting with a walkthrough. Also remember the teacher, as an employee, has a right to view any air quality testing results provided during this process.  

According to EPA, “Teachers can be powerful advocates for creating healthy indoor environments, including improving school indoor air quality. As they are on the front lines, teachers can perceive when IAQ changes affect students and themselves. By being involved in creating a clean and healthy learning environment, teachers can promote health, wellness, and academic productivity.”

If you want to be more involved with the indoor air quality of your instructional space and/or associated areas, reference the links below from EPA’s website under the heading Resources for Teachers, Staff, and Health Professionals.

Teacher’s Checklist  
https://www.epa.gov/sites/default/files/2014-11/documents/teacherchklst.pdf

Teacher’s IAQ Backgrounder
https://www.epa.gov/sites/default/files/2014-11/documents/teacherchklstbkgd.pdf

References 

• OSHA: Indoor Air Pollution in Schools. https://www.osha.gov/indoor-air-quality/schools
• EPA Indoor Air Quality. What are the trends in indoor air quality and their effects on human health? https://www.epa.gov/report-environment/indoor-air-quality 
• EPA Indoor Air Quality in Schools: Reference Guide for Indoor Air Quality in Schools. https://www.epa.gov/iaq-schools/reference-guide-indoor-air-quality-schools#IAQRG_Section1
• EPA Indoor Air Quality in Schools: Take Action to Improve Indoor Air Quality in Schools https://www.epa.gov/iaq-schools/take-action-improve-indoor-air-quality-schools
• Indoor Air Pollution, Related Human Diseases, and Recent Trends in the Control and Improvement of Indoor Air Quality. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7215772/ 

NSTA Chief Safety Blogger Dr. Ken Roy wishes to sincerely thank Gregory Kaczynski, Building Science Project Manager, TRC Environmental Corporation, Windsor, Connecticut, for his professional review of this commentary.

Submit questions regarding safety to Ken Roy at safersci@gmail.com. Follow Ken Roy on Twitter: @drroysafersci.