In what felt like the blink of an eye, offices closed, entire teams transitioned to digital-first operations overnight, and a workforce that rarely worked remotely before were forced to set up makeshift home offices as they quickly adjusted to the “new normal” during the COVID-19 pandemic.
Now, we begin to see signs of progress and the rush to reopen is real - but it certainly isn’t a race. As businesses are tasked with developing reopening plans, many employers and building owners are asking the same questions: How do we ensure the safety of our occupants? And just as importantly, how do we limit the spread of COVID-19 in indoor spaces?
There are quite a few steps we can take, but today we are going to turn to the role indoor air quality monitoring plays in fighting the coronavirus and share some key insights to help you understand what indoor air quality metrics to measure and what each of them say about the health of your indoor environment.
So, how do we create safe indoor environments with better air? To answer that, we first need to understand how SARS‑CoV‑2 (the virus that causes COVID-19) spreads indoors.
How Does COVID-19 Spread in Indoor Environments?
For a full breakdown of how COVID-19 spreads, make sure to check out our in-depth article:Is COVID-19 Airborne? Busting Myths About the Transmission of the Novel Coronavirus.
In short, when people cough and sneeze, they expel tiny water droplets that contain salt and organic materials. Anyone infected with the COVID-19 will also expel the virus, which is less than 0.15 μm in size, in their droplets.
As these water droplets containing the virus evaporate inside buildings, the microscopic matter will become small enough and light enough to stay suspended in the air. Over time, the concentration of the virus will build up and disperse in the form of particles which will increase the risk of infection for people occupying the buildings – particularly if there is stagnant air. Lack of adequate ventilation in many indoor environments, such as workplaces and residential buildings, then, increases the risk of airborne transmission of the novel coronavirus.
As of writing this article, there is no technology to detect or calculate the concentration of the COVID-19 virus in a given indoor space. However, new studies, coupled with existing strategies, might help us gauge the likelihood of presence and survival of the coronavirus in our indoor environments.
Key Findings: How Does Poor Indoor Air Quality Increase the Risk of COVID-19?
In a recent study, SARS-Cov-2 virus was found present on particulate matter. This means that the virus could be carried over longer distances, increasing the number of people infected. Further, the study suggests that the coronavirus particles can attach to PM10 particles — the same stuff as PM2.5, just in slightly larger particles — and stay suspended in the air for long periods of time. As PM10 and PM2.5 are two of the most commonly found pollutants in indoor air, occupants of highly polluted spaces face the increased risk of exposure to the coronavirus.
Similarly, SARS-CoV-2 can survive for some time outside of infected cells, including in indoor spaces. Depending especially on air temperature and relative humidity (RH), the viability of viruses in a given environment varies. In this instance, it has been discovered that SARS-CoV-2 survival increases significantly below the optimal range of 40 to 60% RH — the perfect environment for the virus to survive for several days.
How Can We Use Indoor Air Quality Monitoring to Fight COVID-19?
This all sounds pretty dire, but not to despair — there are ways you can fight back! Yes, SARS-Cov-2 is a novel virus, and more research is needed to nail down the exact relationship of indoor air pollution levels and COVID-19 transmission. But preliminary results give us a look into how seemingly small air quality changes might be causing large differences in virus transmission levels. And luckily, there are various indoor air quality metrics you can start monitoring today to track the overall health of your indoor air. By implementing indoor air quality monitoring technology, you will be better equipped to take the right COVID-19 precautions for your indoor space, and measure the effectiveness of your ventilation and filtration provided by your building's HVAC system.
Indoor air quality monitors like the Sensedge and the Sensedge Mini measure a number of parameters which we know are associated with the transmission of viruses including COVID-19. Among those, PM2.5 is the first to come to mind — and for good reason. Found in abundance in most indoor environments, PM2.5 allows viruses like SARS-Cov-2 to travel longer distances, while increasing their viability. By monitoring PM2.5 levels, you will gain insight into how effective your ventilation and filtration efforts are in fighting the coronavirus — whether it's a HEPA filter or an HVAC system. Using those insights, you can then identify actionable items like replacing your filters to meet COVID-19 standards, or adjusting ventilation rates to limit harmful pollutants from filling the ambient air.
Relative Humidity (RH)
In a similar vein, relative humidity (RH) is one of the indoor air quality parameters used to determine indoor air health. As we saw before, humidity levels outside the optimal range of 40% - 60% RH can create an unhealthy environment where viruses thrive, and survive on surfaces for days. By monitoring relative humidity, you ensure your building's climate control equipment is operating at its ideal capacity and allow the occupants to make any necessary adjustments to maintain the proper %RH, while keeping COVID-19 at bay.
As your building gradually reopens and the occupants return, you might want to consider monitoring CO2 levels as well. It's another important indoor air quality parameter that is also a great proxy to determine building occupancy levels. The more occupants there are in a room or building, the more CO2 is released into the air. To prevent CO2 levels from rising too high and contributing to the airborne concentration of COVID-19, outside air must be deliberately brought into the building through a ventilation system. Without knowing what your CO2 levels look like, you might end up unnecessarily overworking the ventilation system, wasting energy. By monitoring CO2 levels and providing ventilation on an as-needed basis, you can maintain healthy air quality and reduce your energy use at the same time.
Finally, as the rate at which we clean and sterilize your space will naturally increase thanks to the novel coronavirus, your occupants might be more susceptible to high TVOC levels. TVOCs — commonly found in cleaning supplies— are a group of dangerous chemicals that off-gas into the indoor air we breathe. Monitoring TVOC levels can provide insights and help make more informed building operations decisions. For example, you might discover that scheduling all cleaning before or after work hours allows TVOC levels to go back to normal before building occupants are back for the day. This way, you would be able to keep the space clean and sanitized without sacrificing your occupants' well-being.
With no data driving your building operations, you have no insights to make informed decisions. Air quality monitoring technology exists for this very reason; combined with existing HVAC and building management systems, indoor air quality monitors are imperative to understanding the safety of the air you breathe, the efficiency of your ventilation, and the performance of your filtration efforts.
In the wake of COVID-19, monitoring these activities will have a significant impact on your indoor air quality, and having monitors in place will allow you to identify trends and make decisions on ways to improve and provide the best environment for your occupants. Curious to dig deeper into these metrics before your building reopening? Learn more with our air quality guide for buildings below!