Covid-19 and PM 2.5: The Stakes Have Risen for Hospital Building Health

Vanishing air pollution has been a big Covid-19 story, told in dramatic before-and-after images: Skyscrapers once obscured by a yellowish haze suddenly appear in sharp focus, now that factories have closed and traffic is sparse.

But as nations emerge from lockdown and cities roar back to life, that toxic haze will reappear — and, as before, will seep into our medical centres, posing risks to patients and healthcare workers alike.

Except this time, with a new pathogen in our midst, the stakes for hospitals will be higher.

For the foreseeable future, healthcare facilities will be contending with Covid-19, a disease with strong and documented links to polluted air.

Two robust studies, one American and one Italian, have found that Covid-19 patients with more exposure to particulate matter face a higher risk of dying. The researchers focused on PM2.5, toxic particles small enough to penetrate lung tissue.

“If you’re breathing polluted air and your lungs are inflamed by the disease, you’re going to get very, very sick,” cautioned biostatistician Francesca Dominici, Ph.D., a Harvard University Harvard biostatistician and co-author of the American study.

Dr Dominici was referring to long-term PM2.5 exposure, as measured outdoors. However, other research has linked even daily spikes in particulate matter to surges in heart attacks and asthma attacks; still, other studies demonstrate that hospitals are not sealed off from the airborne toxins outside.

“Indoor concentrations of many pollutants can be higher than outdoors,” notes Joseph Allen, DSc, director of Harvard University’s Healthy Buildings Program and a forensic investigator in hospital disease outbreaks.


As a group, hospital patients are highly vulnerable to the health risks of air pollutants. Covid-19 patients, many of them intubated or ventilated, may be the most vulnerable among the vulnerable.

As these patients struggle to survive, what they need least is further exposure to airborne pollutants.

Though lockdowns will ease, the novel coronavirus will persist for some time, as that polluted haze reappears. It’s a worrisome scenario — and one hospitals must prepare for by eradicating indoor particulate matter, especially in wards where Covid-19 patients are treated.

Covid-19 and Pollution Exposure

Air pollution has long been linked to respiratory infection and disease. Just as PM2.5 damages nature, turning streams acidic and depleting soil nutrients, these toxic particles inflame human tissue and deplete immunity.

So when a respiratory virus strikes, those with pollution-impaired lungs and weakened defences are primed to suffer the most.

This proved true when the SARS coronavirus surfaced in 2002.

Patients from highly polluted regions in China were twice as likely to die as those who’d breathed relatively clean air in the previous two months, as well as the previous two years. Even SARS patients from moderately polluted regions in China were 84% more likely to die than those exposed to low pollution levels.

So, the study results on SARS-CoV-2, its wilier cousin, are unsurprising.

“We know fine particulate matter affects the respiratory system. And we know that Covid-19 kills by affecting the respiratory system. So we know, by science, that getting [the disease] is like adding gasoline to the fire,” says Harvard’s Dr. Dominici, co-author of the American study.

In her study, patients from heavily polluted counties in the United States were 15% more likely to die from Covid-19 than patients in counties with cleaner air.

Just a small increase in PM2.5 exposure corresponded with a large increase in the Covid-19 death rate. The impact of PM2.5 exposure on death from Covid-19 was 20 times greater than the impact of pollution exposure on death from all causes.

The Italian results were even starker.

Northern Italy is among Europe’s most polluted regions, due largely to an unlucky combination of climate and geography: wind is rare, and climatic inversions aren’t. Among patients in the region stricken with Covid-19, the death rate over a one-month period was an astonishing 12%, compared to 4.5% elsewhere in Italy.

“It is well known that pollution impairs the first line of defence of upper airways,” wrote the authors, in Environmental Pollution. It only follows, they observed, that residents who inhale more pollutants would be more vulnerable to respiratory infection.

For the vulnerable, it doesn’t take a lifetime of pollution exposure to trigger a poor health outcome; a few days of inhaling highly toxic air may do the job.

Diabetes, COPD, Parkinson’s disease, asthma, tissue infections, kidney failure — hospitalizations for all these conditions surge on days when air pollution spike.

What’s more, it doesn’t take exceedingly high levels of pollution to wreak havoc on the health of a vulnerable person.

In an American study, the link between exposure to fine particulate matter and hospitalizations held even when the daily air pollution levels were lower than current World Health Organization standards.

The health dangers of air pollution are “significantly larger than previously understood," warned biostatistician Yaguang Wei, Ph.D., the study's lead author.

Likewise, Australian researchers, using data from Japan, found that for older patients, even brief exposure to relatively low levels of particulate matter can increase risk of cardiac arrest. In their study, over 90% of the heart attacks occurred when pollution levels were below WHO standards.


“There is no safe level of air pollution,” cautioned study co-author, Kazuaki Negishi, M.D., a cardiologist University of Sydney School of Medicine.

Cleaner Hospital Air: Safer for Patients and Healthcare Workers Alike

Air pollution inside hospitals was a concern long before the novel coronavirus jumped from animals to humans.

We know this microscopic mixture of dust, soot, and chemical particles can travel hundreds of miles and can waft indoors via doors and windows. Other airborne toxins, such as volatile organic compounds (VOCs), originate inside buildings, emitted by building materials, cleaning supplies, even shampoos and lotions.

Particulate matter, like dangerous bacteria and viral particles, also can hitch a ride on clothing, only to be launched airborne when a lab coat or gown is removed.

Even among healthy people, PM2.5 can irritate the eyes and lungs, trigger headaches, exacerbate allergies, and impair memory and the ability to do simple math.

By contrast, studies show, breathing clean air on the job makes you feel better and think more clearly, especially in a crisis.

A few years back, Harvard’s Joseph Allen sent architects, managers, and other professionals to work amidst varying levels of airborne pollutants. He then challenged them with a series of simulated scenarios, such as taking charge in a crisis as an emergency coordinator.

The subjects had to plan, prioritize, and sift through loads of information under high-stress conditions.

“We found that breathing better air led to significantly better decision-making,” Dr Allen reported.

For hospitals, of course, crises occur daily, decisions are matters of life and death, and these pollution-sensitive skills are essential, more so than for the typical manager.

Dr Allen suspects the coronavirus pandemic will turn clean indoor air into an important commodity, one that business leaders and landlords will leverage “as recruitment tools and sources of competitive advantage.”

Hospitals, of course, have different priorities. Recruitment and competition take a back seat to saving lives and protecting healthcare workers.

Given these high stakes, hospitals must go well beyond measures used by business leaders, deploying medical-grade technology to eradicate the pollutants floating about their facilities.

Unlike SARS, Covid-19 will not vanish any time soon. A vaccine is far off, and more distant still is the day when vaccine rates are high enough to vanquish the disease.

As the WHO has warned, “the worst is yet ahead of us.”

Eyeing this future, Dr Allen advises an all-out attack on Covid-19: “That means unleashing the secret weapon in our arsenal — our buildings.”

By deploying a single air dis-infection technology, hospitals can achieve multiple goals: mitigating the spread of SARS-CoV-2 and eradicating the airborne toxins that may compromise the recovery of patients and the quick thinking of doctors and nurses.

Ultra-low energy plasma units by Novaerus not only kill  99.99% of MS2 Bacteriophage, a surrogate for SARS-CoV-2 (COVID-19), in 15 minutes according to laboratory studies but also remove 99% of PM2.5 inside a chamber in 6.26 minutes.

These portable units operate 24/7 and are safe for continuous use around the most vulnerable patients.

For these reasons, hospitals worldwide are installing Novaerus units in ICUs and Covid-19 wards.

It’s clear that cleaner hospital air may benefit not just coronavirus patients but also the staff who care for them.

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