Verifying Engineering Controls: The Critical Role of Emerging Technology
Sponsored by SafeTraces
2020 has been a wake-up call for the built environment. For years, indoor air quality has been a problem hidden in plain sight. Scientific research has detailed the scale and extent of this challenge, as well as the real human consequences evidenced in degraded cognitive function, illnesses, and absenteeism.
However, the current pandemic has elevated indoor air quality to an urgent matter of life and death. Infectious disease experts, including the CDC, have arrived at consensus regarding the significance of airborne and aerosol-based transmission of SARS-CoV-2. Moreover, viral infection has shown to be 18 times more likely indoors than outdoors, leading to a state of paralysis in much of the built environment.
The good news is that we know that air ventilation and filtration can make a major difference in mitigating airborne exposure risk indoors. According to the AIHA’s Guidance Document “Reducing the Risk of COVID-19 Using Engineering Controls” (PDF), “Engineering controls (including ventilation and filtration) that can keep infectious aerosols at very low levels indoors offer the greatest promise to protect non-healthcare workers and other vulnerable populations as we reopen our businesses and workplaces.”
The bad news is that the pandemic has exposed a critical gap in the toolbox of industrial hygienists and mechanical engineers—a science-based, data-driven diagnostic solution for verifying engineering controls in real-world indoor environments. Today, many rely on carbon dioxide monitors, computational fluid dynamic modeling, mathematical calculations, and even smoke and bubble testing, none of which accurately approximate the risk of infectious aerosols.
Our company offers the first diagnostic solution for verifying ventilation and filtration-focused engineering controls, specifically for infection control, through a novel methodology that safely mimics aerosol mobility and exposure levels with DNA-tagged tracer particles. During the pandemic, we have supported clients spanning commercial real estate, industrial plant operations, and public infrastructure, providing us the following key insights:
- Assumptions vs. ground truth: Similar to traditional building commissioning studies, our test results invariably reveal important discrepancies between our client’s assumed understanding of airflow patterns, airborne exposure levels, and HVAC system performance in their facilities relative to our assessment findings. Frequently, we detect unanticipated airflow between building areas, mechanical faults in the HVAC system, among other surprising findings that would otherwise be unknown to the client and that increase occupational health and safety risk.
- Multiplier effect of airborne interventions: Our test results indicate a valuable multiplier effect of ventilation and filtration, evidenced by lower detection levels of our tracer particles in both air and surface swab samples. In other words, effective ventilation and filtration not only can reduce airborne exposures by removing infectious aerosols in the air; it also can reduce fomite exposures by preventing infectious aerosols from depositing on surfaces and infecting building occupants.
- Importance of in-room interventions: Our test results clearly and consistently indicate greater efficacy in reducing airborne exposures with in-room interventions like portable HEPA filters relative to HVAC system interventions like MERV-level upgrades. Our tracer particles often don’t make it to in-system filters, whereas portable HEPA filters remove our tracer particles closer to the point of risk where infected occupants are likely to infect others. Thus, several clients have reevaluated the soundness of proceeding with MERV-level upgrades when considering their occupational health and safety benefit relative to their financial cost.
In conclusion, it is paramount for all occupants and professionals to understand if the HVAC system and engineering controls are actually helping or not in preventing the spread of COVID-19. Emerging technologies have tremendous potential to provide a more accurate understanding of real-world occupational health and safety risk and mitigate this risk based on science and data.