Indoor air quality (IAQ) is defined as the quality of air in the workspace environment in places like school classrooms and laboratories. With the advent of the mid-1970s energy crisis and its affect on IAQ, much attention has been given to this issue. Although OSHA does not have legal IAQ standards, there are other related Occupational Safety and Health Administration (OSHA) standards such as ventilation and air contaminant standards. Key factors leading to IAQ issues according to OSHA include the following:

• Improperly operated and maintained heating, ventilation, and air conditioning 
• (HVAC) systems
• Overcrowding
• Radon
• Moisture incursion and dampness
• Presence of outside air pollutants
• Presence of internally generated contaminates
• Common Pollutants
• Biological contaminates (e.g., Flu, COVID-19, etc.)

A major contributor to poor lab IAQ is a lack of appropriate preventative maintenance for ventilation systems and biological pollutants such as pollen, mold, animal dander and more, which will potentially support the growth of viruses, fungi, and bacteria. This can lead to serious health issues in the science and/or STEM lab.  

Additional legal standards include the National Fire Protection Association (NFPA) 45–Standard on Fire Protection for Laboratories Using Chemicals. This standard requires specific ventilation criteria such as non-circulating air in the lab to prevent buildup of flammable gases, vapors, particulate matter, and other potential air contaminants. This standard and others specifically note the following requirement relative to lab air circulation: “All lab rooms shall use 100% outside air and exhaust to the outside. There shall be no return of fume hood and laboratory exhaust back into the building.” (See this website.) The purpose of these standards is to ensure that lab ventilation systems will be designed so that chemical fumes, vapors, or gases originating from the lab shall not be recirculated.

Depending on the type of contaminant, symptoms of poor IAQ can vary. The biggest clue is employees and students feel ill when in the science lab or other locations in the school, but their symptoms dissipate once they leave the site. Symptoms might include irritation of the eyes, nose, throat, and lungs; fatigue; and headaches. A major element in poor IAQ is water or excessive moisture. With this situation, the growth of bacteria, fungi, and mold are facilitated and can lead to serious respiratory issues such as allergic reactions, asthma, coughing, wheezing, shortness of breath, sinus congestion, sneezing, nasal congestion, and sinusitis. Leaks in lab plumbing, ceiling leaks, and other sources of moisture over time foster mold growth if not rectified.

In science and/or STEM labs, chemical pollutants like gases and vapors can cause IAQ issues. Chemicals such as acids, toxins, flammables, and other experiment by-products are major factors contributing to IAQ problems. Burning or heating of chemicals, mixing of chemicals, and other means of developing chemical products with poor ventilation can cause poor IAQ.

Other sources--mainly from physics and STEM labs--result from particulate matter sources. Suspended particles resulting from drywall dust, wood dust, silica, and other sources resulting from use of power tools (drilling, sawing, etc.) are also sources contributing to IAQ issues.

This begins with eliminating/engineering the hazards out, then implementing administrative controls such as policies and procedures, and lastly, if the first two lines of defense are not feasible or insufficient, incorporating the use of personal protective equipment (PPE).

Eliminating/Engineering Controls
Eliminating the source of the pollutant should always be the first option, and  starts with source management. This would include removal, substitution, and enclosure of pollutant sources. This is considered the most effective method when applied in a practical manner. For example, when dealing with alcohols in lab, look for one with a low VOC level. On the Safety Data Sheet (SDS), typically in the section called Physical Properties, you may find the total amount of VOC contained in the product. (See this website.)

Engineering controls are the next alternative choice to control exposure. Examples include local exhaust systems, fume hoods, spray booths, etc. One way to increase the amount of fresh air is to adjust the rate of air exchanges per hour. This can be done by increasing the ventilation fans to increase air exchange, thus bringing in a higher amount of fresh air. This is especially helpful in dealing with biologicals like COVID-19 virus, mold, etc. This approach reduces the exposure of room occupants to these hazardous biologicals. Again, make sure a preventative maintenance schedule is adhered to for engineering controls. For example, a fan belt could be broken on the fume hood exhaust system. The fan motor is operational, but without the belt, the fan is not operational, rendering the fume hood sterile operation-wise!

When elimination and engineering controls prove to be infeasible, administrative controls should then be considered. Administrative controls fall into three general areas: work schedules, training, and housekeeping. If elimination, engineering, and administrative controls prove to be infeasible or insufficient, PPE should then be used to control exposure to indoor pollutants by use of appropriate gloves, protective clothing (e.g., apron or lab coat), eyewear, and footwear where necessary.

Adequate air ventilation is a critical part of ensuring good IAQ when using sanitizers and disinfectants. These can have hazardous chemicals that vaporize. Poor IAQ allows occupants to breathe in these hazardous chemicals and potentially cause health issues. To make sure the ventilation system is operating appropriately, the school’s maintenance staff should consider using a checklist that addresses these areas: 

• outdoor air intakes
• system cleanliness
• outdoor air supplies
• air distribution
• room exchanges/hour
• exhaust systems
• quantity of outdoor air

A sample complete ventilation checklist can be downloaded from this website.

Instead of opening windows and bringing in pollen, particulate, and other sources of unfiltered air pollution, it is better to have an air ventilation system running at top efficiency to increase room exchanges/hour so as to also increase the amount of fresh air being filtered. Maintainers should use upgraded filters in HVAC systems like MERV 13 or higher.  

Other additional changes could be made to enhance the quality of air in the teaching/learning space. For example, HEPA filters could be added provided that the HVAC can be appropriately designed to handle them. In addition, a UV-C light scanner device could be added. The HEPA captures the biologicals and viruses, and the UV-C light scanner neutralizes them. Ionizing air purifying units also could be installed, which again can neutralize the virus. 

Indoor air quality can be a challenge with the variety of biological, chemical, and physical hazards produced in the science or STEM lab. An IAQ investigation requires research and investigation of the problem to help identify the potential pollutants. If air monitoring is necessary, comparative samples from non-problem areas of the building are a useful tool for determining what the possible contaminants are. Also, samples should be tested outside of the building in the general environment. As a reference guide, ASHRAE 62.1-2016 lists common contaminant levels for these and other specific chemicals.

As noted at the beginning of this blog post, OSHA does not have a formal IAQ standard. However, it does enforce IAQ issues that pose a recognized hazard via the OSH Act General Duty Clause Section 5(a)(1).

OSHA does review and recognize national consensus standards as appropriate to IAQ issues. The standards provide direction from their originating organizations. Examples include the following:

ASHRAE

62.1-2016 - Ventilation for acceptable indoor air quality. Specifies minimum ventilation rates and indoor air quality needed to avoid adverse health effects to human occupants.
55-2013 - Thermal environmental conditions for human occupancy. Specifies the combinations of indoor thermal environmental factors and personal factors that will produce thermal environmental conditions acceptable to a majority of the occupants.

ASTM
E1971-05(2011) - Standard guide for stewardship for the cleaning of commercial and institutional buildings 

Additional Sources

Indoor Air Quality in Commercial and Institutional Buildings, Occupational Safety and Health Administration, Publication 3430-04 2011

EPA Indoor Air Quality Information Clearinghouse

NIOSH Guidance for Indoor Air Quality Investigations

Evaluating a Persistent Nuisance Odor in an Office Building-Maryland, National Institute for Occupational Safety and Health (NIOSH), May 2011.

Listen to your body! If you have symptoms you experience at the workplace but not at home, contact your facilities department or health and safety compliance department to help determine what might be causing these issues and to help prevent future health hazards!

Submit questions regarding safety to Ken Roy at safersci@gmail.com or leave him a comment below. Follow Ken Roy on Twitter: @drroysafersci.