post-covid, air quality ratings are becoming mainstream — but does that mean it's safe to breathe deeply?
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measuring virus transmission risk is like trying to see the invisible. getty
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matt farrell, vice president of operations for to live, remembers the impact the covid-19 pandemic had on live entertainment.
“it was it was devastating for us,” says farrell. “at peak times, we’d be processing 600 checks a week between all of our permanent, part-time and contract staff. and then it went down to 30 very quickly.
“it was it was really, really hard to see. so many so many colleagues and friends that have worked with us for so long.”
as the pandemic raged on and the concept of sharing air with another person was increasingly being seen as a risk, farrell says to live invested several hundred thousand dollars upgrading ventilation and airflow systems in their performance centres. high-tech uv filtration systems were installed, upgrades to air filters that could catch vaporized respiratory droplets were made. and yet, the irony of the care and effort in these systems — unlike a new show or a name going up in lights — is they are tucked away, perfectly designed to be unnoticeable when patrons finally returned.
“that’s hard to communicate, to say, ‘hey, these are the things we’re doing,’” says farrell. “you can say great things, but what does that mean? where is the context to it?”
operations staff are looking for ways to demonstrate the multitude of invisible measures they have taken to improve air quality, considering the only time many notice room air is when something has gone decidedly wrong. who thinks to compliment a restaurateur on the lack of smoke coming from the kitchen? when attending a packed holiday party, who considers good airflow — not too strong so guests are cold, not too weak so guests feel stifled — riveting conversation?
as the demand for showing air quality has risen, companies and tech firms have attempted to fill in the gaps. air quality rating devices are more accessible than ever and many companies have begun offering consults and airflow mapping services, all with an aim to demonstrate the impact of a building’s ventilation.
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in toronto, a new initiative called breathe easy “provides measurable insights on the safety of public and private spaces, and the information to improve if needed,” according to their website. created by poppy health, ainsworth inc, surgically clean air, and two small fish ventures, their work measuring “air risks” in more than 120 locations in the downtown core recently got a nod from toronto mayor john tory.
while poppy health provides various ways of measuring air quality, the breathe easy rapid test is conducted by releasing a water-based mist with special “tracer particles.” sensors placed three feet away from the source of mist determine the concentration of this tracer in the air over a 15-to-20-minute period, with a score assigned for how many particles the sensors could pick up. the higher the score, the more the particles degraded, and the less likely someone will theoretically be to encounter exhaled respiratory particles that could possibly be carrying viruses.
the rapid test claims to show real-time effective air change rate. air change rate is a measure of how many times a specified volume of air will be replaced by air from another source (for example, outside or from filtration systems), and has become a key part of the post-pandemic ventilation conversation.
according to recommendations by the american society of heating, refrigerating and air-conditioning engineers (ashrae), to reduce risk of exposure to airborne infections, buildings should follow local standards for air exchange with outside air. canadian ventilation standards vary based on the purpose of the building, but for residential units a rate of roughly 5-10 litres of fresh air per second per occupant is considered a starting point.
for recirculated air, ashrae writes buildings should employ a combination of air cleaners and filters to achieve “merv 13” or better performance. (minimum efficiency reporting value (merv) of 13 means the system is 85 per cent efficient at capturing particles 1—3 micrometers in size. respiratory droplets, including those carrying sars-cov-2 virus particles, roughly fall into this range.) however, the efficiency of a filter also relies on how well it is installed, with no gaps for air to blow past.
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areas that received a platinum ranking from the breathe easy campaign include the little canada “little toronto” exhibit room, the public lobby in the atrium building on bay street and the kitchens in the iq offices co-working spaces on king street west. to live’s meridian hall and st. lawrence centre for the arts each ranked gold, while toronto’s path (specifically the public walkway near 100 king street west) received some of the lowest scores available on their website and did not qualify for a ranking.
measuring the invisible
patrick leavey, director of operations at little canada, says one of his key concerns is keeping the attraction clean for the school groups that come through. the goal is to maintain a unique, but safe, experience — especially as concerns of rsv and an intense flu season have many parents concerned about the choice to return to in-person activities.
the rapid air test showed their operations staff where things were going well and also where inefficiencies could be addressed, leavey explains. finding places where air stays stagnant was an opportunity to place a new purifier. realizing the furnace ventilation only turned on when the furnace did was another opportunity — why not run the ventilation all the time?
“we’re not just setting it and forgetting it, we’re taking an active approach,” says leavey. “these are things that you just don’t want to place and just leave them. once you’ve found the right spot and you’ve got the right settings, you want to make sure that everything is on.”
sam molyneux, co-ceo of poppy health, says there are many ways to improve the air quality of the room. the trick is to understand each unique space and create an approach that makes sense for their goals.
“there’s a variety of mechanisms that are at play in any room,” molyneux explains. “one of them is the airflow. one of them is the amount of dilution that’s happening into the room. another one is whether air purifiers are running. and there’s many others, including particles sticking to surfaces and people — all these mechanisms are at play.”
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and while it may seem intuitive that air volume — large, open spaces — would be the best predictor of a higher score, molyneux says the rooms with the most air motion tended to do better. air purifiers on the floor, doors constantly opening and closing — all things that encourage air to circulate tended to contribute to a higher score.
airflow is constantly changing
while encouraged by the prospect of analyzing air quality throughout buildings to find areas for improvement, jeffrey siegel, professor of civil engineering at the university of toronto, warns against labelling building air as safe versus not safe. patrons should be aware that conditions — and ratings — can change in an instant.
“[in] a typical university classroom, seeing a variation by a factor of 10 over a few weeks’ time is not uncommon,” say siegel. “in my own house, i have done things like measure the exchange rate for a year. and again, a variation of a factor of four or five over the course of the day can certainly happen.”
something as simple as the number of people within a room can have a large effect on how air flows. the changing environment also has an impact — dry air will cause moisture droplets to shrink, changing how far they can travel. it is also possible to game a rapid test by doing things like turning on a filtration system that is usually kept off.
the patrons themselves also play a role in keeping everyone safe. standing right next to someone with a contagious virus will always increase the risk of being in the spray zone, so following other public health guidelines (like staying home when sick) is still paramount.
as the air-quality conversation, and technology, continues to evolve, farrell is looking forwards to a busy holiday season with to live. ticket sales are back up, and audiences are once again coming together to gasp, laugh, and breathe in the air of a good performance.
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update: the headline of this article has been updated
emma jones is a multimedia editor with healthing. you can reach her at emjones@postmedia.com or on instagram and twitter @jonesyjourn.
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