OccuSafe Industrial Hygiene Consulting

A significant cause of the spread of COVID-19 is through airborne aerosols. By installing or increasing outside air through ventilation, viruses in the air can be greatly reduced. When used with other best practices such as social distancing, wearing face coverings, cleaning and disinfecting surfaces, ventilation should be part of a facility plan to protect employees who work indoors.

The amount of ventilation or ventilation rate should be directly related to the number of people in an indoor environment. Greater airflow may be needed in high-traffic areas such as aisles. One effective test is monitoring carbon dioxide (CO2) levels. In most indoor areas, the dominant source of CO2 is human activity.Maintaining CO2 below 1000 ppm is indicative of adequate ventilation. For areas where work is sedentary, levels up to 1500 ppm may be acceptable. If the level of CO2 does not meet these benchmarks, greater ventilation may be needed. An inexpensive hand-held carbon dioxide meter can be used to make the determination. Measurements should be taken when concentrations are highest, just before lunch and the end of a shift. The amount of ventilation may also be reduced by lowering occupancy or by staggering shifts. Engineering controls such as removing partitions that interfere with airflow may also be effective. Ultraviolet light and other disinfecting devices as well as air filters can be added to ventilation systems to contain and kill the corona virus.

If it is determined that further ventilation is needed, a thorough review of the current ventilation system should be conducted. Each part of the system should be inspected to determine if it is working as designed or if there have been modifications that have altered its operation. In addition, changes by individuals working in the area and maintenance records should also be noted. Airflow measurements should be taken at various locations on the fans and ducting. A qualified maintenance person, ventilation engineer, or industrial hygienist should conduct this evaluation.

Once the evaluation is completed, an overall plan should be made to implement needed changes. Maintenance procedures, system testing, responsibilities and employee training should be included. This plan is necessary to fight the current pandemic and mitigate any biological events that may occur in the future.

Be safe, be healthy, be six feet apart!