The conversation on air quality in India is often seasonal, resurfacing around the winter months of polluted air. But Covid-19 will likely make this focus—especially on indoor air quality—an everyday phenomenon.
If India hopes to reopen offices, cinema halls, malls, and schools fully and safely in the future, ventilation will be a key aspect of a social life that coexists with Covid-19. This is because “closed, crowded spaces with close contact—the ‘three Cs’—have been consistently shown to be associated with spread; a combination of the three being often associated with superspreader events,” says Dr Lancelot Pinto, consultant pulmonologist at Mumbai’s Hinduja Hospital.
By this point in the pandemic, it is also clear that Covid-19 is an airborne disease that spreads not just through a direct and close-contact aerosol exchange, but also through the air shared in closed spaces. Add to this mix more transmissible variants like alpha (first detected in the UK) and delta (first found in India), and it becomes “imperative for us to pay close attention to indoor air quality, especially in spaces that are air-conditioned and poorly ventilated,” Pinto explains.
While most buildings would need structural changes, there are solutions that can be implemented immediately.
How to ventilate indoor places for Covid-19
Most of these solutions are basic and involve cracking open a window and ensuring there is greater air exchange per hour. (Air exchange per hour is the number of times the entire volume of air in a room is completely replaced.)
But this may be a double-edged sword in India. In some cities with clean air and moderate climates, creating a draft for fresh air to circulate is possible and ideal. “Fans can be added to help lower temperatures, improve ambient comfort, and help air circulate,” Pinto says. But these need to be placed in ways that do not cause air to be blasted from one person to another (exhaust fans might help redirect air). Pinto says. “There would be challenges to manage this in the monsoons, and one would have to think of novel and tailored solutions to prevent discomfort due to humidity.”
But cities in northern and central India, with high levels of particulate matter pollution, would have to consider the risk of Covid-19 versus the risk of oxidative stress from poor air quality, says Jai Dhar Gupta, founder of Nirvana Being, a protective solutions company. “For eight months a year, our air quality is so bad that it’s not ideal to create ventilation with polluted air from outside,” he says.
For this, an HVAC (heating, ventilation, and air conditioning) consultant can work with companies and institutions to install filtration devices—such as HEPA filters that weed out small particles and even some pathogens, and ultraviolet machines to kill disease-causing viruses—in existing air conditioning set-ups. But these tend to be expensive solutions. In the case of cinema halls and multiplexes, these devices would be the only way to ensure moviegoers can return without the fear of contracting the disease. Several cinema halls in large Indian cities like Delhi and Mumbai have already installed UV filters for indoor air.
Technology aside, ventilation, according to Pinto, continues to remain the most important and least expensive aspect of ideal indoor air quality.
Ventilation in schools and polluted cities
The only way to ventilate, Gupta says, is to bring in outside air indoors. In rural or semi-urban healthcare centres, for instance, where resources and access to technology are limited, simply ensuring that a draft is created for air to pass through will mitigate the risk of Covid-19.
But in cities—especially in schools that are now air-conditioned—it is dangerous to have split air conditioners when there are over 30 people in one closed room. “Schools are a hotbed for germs and contaminants and that is how our kids develop immunity,” Gupta says. “But this priority should be different in a post-Covid environment.”
Gupta suggests that public places must follow the simple rule of “don’t share the air.”
“Split air conditioners are the worst innovation of our generation because unlike window ACs, these only cool and circulate indoor air,” Gupta says.
And opening a window or turning on an exhaust fan may not be the most energy-efficient solution, but one that may be necessary. The other alternative is to add nano-filter sheets to existing air conditioners that filter out viruses and bacteria from indoor air to a great degree. Urban Indian homes, offices, and public places are now also familiar with the concept of an air purifier, which can be used around the year instead of only during peak pollution months.
Gupta suggests a four-point baseline protocol that should help improve indoor air quality:
- While viruses cannot be monitored through a device, a simple CO2 filter will be able to detect if there is ample ventilation or the air indoors is stale.
- With CO2, a PM2.5 monitor can detect how polluted the air is. This is doubly important in the context of Covid because viruses are likely to attach themselves to particulate matters and remain airborne.
- Viruses thrive in cool conditions. Gupta says indoor spaces should maintain a temperature of 25°C or above, even if it means sacrificing a little ambient comfort. This will also, in turn, make buildings more energy-efficient.
- Viruses thrive in dry environments. Ideally, humidity levels of 50-60% should be maintained indoors.
But to truly make indoor spaces safe from Covid-19, many buildings need a complete overhaul.
Designing buildings that aid living well
“It is sad that I haven’t seen too many buildings in India designed for human wellbeing,” Gupta says. “All this ventilation is basic stuff. Why wasn’t this already followed over the last 30-40 years?-What is the role of an HVAC consultant if all of these mechanisms are not already in place?”
He recommends that strict protocols will need to be put in place and the government would need to incentivise institutions to include ventilation in their blueprints. “It is mind-boggling to see that we think we can get back to work safely—after decades of cutting corners,” Gupta says. Till these spaces can be made safer, masking up indoors is here to stay, coupled with keeping indoors sparsely occupied.
As a policy focus, countries have experimented with encouraging outdoor Covid-safe behaviour, such as restaurants on sidewalks. “A significant proportion of indoor overcrowding occurs in religious places, gatherings in halls for events such as weddings and family functions, and in crowded workspaces,” says Hinduja Hospital’s Pinto. “We need to try and actively encourage these interactions to move outdoors, or online, whenever feasible, with measures to shield individuals from the vagaries of the weather.”
From a public health perspective, Pinto says this will also bode well for India, which has close to a third of the world’s burden of tuberculosis, also a disease that spreads through ill-ventilated spaces. “Even pre-Covid, we should have been cognizant of the need for better ventilation indoors, and an active move to open, well-ventilated spaces,” he adds.