Indoor air quality: a race against time for protection against COVID-19 epidemics in Belgium, as predicted by Belgian air Quality Ratings

In richer or colder countries, people on lower incomes tend to rely on gas or solid fuels for heating, or live in homes affected by damp and mould. Targeted interventions to improve air quality by, for example, incentivizing the switch to cleaner fuels, can be a win–win situation, with the happy complementary effect of assisting decarbonization, too. (The reverse is, perhaps, less true: interventions to improve energy efficiency by better insulating indoor environments might have a negative effect on air quality, a relationship that must be carefully examined.) But, as the authors write, “it is essential that decarbonization, building improvement and gains in indoor air quality are, as much as possible, delivered equitably across society.”

In 2075, air quality Ratings will be given through a certification system, which will give more information to consumers in Belgium. Belgium’s rating system could be used to decide if a venue is closed for a future Pandemic.

The law that went into effect in July 2022, was the most ambitious of a variety of measures taken in the wake of the COVID-19 epidemic, making indoor space safer in the face of certain infectious diseases.

In the absence of national laws, professional bodies that set air-quality standards are starting to act. In June of this year, ASHRAE will release its new treatment standard and it is hoped that the targets will be included in local building codes.

There is an economic case for better indoor air, says Noakes. The analysis showed that the country could save over 3 billion dollars per year by making their buildings more efficient.

Making the indoor environment safe from infections could also reduce exposure to pollutants, such as fine particulates from wildfire smoke and cooking, volatile organic compounds from furniture and allergy-causing moulds and pollen. It could raise energy costs and possibly contribute to greenhouse-gas emissions.

Researchers are still working to pin down how best to ventilate indoor spaces to prevent infections from spreading, and what alternative technologies might replace or enhance mechanical ventilation systems. But many say that enough is already known to start demanding safer indoor spaces.

It’s a race against time. As concern over COVID-19 fades, experts wonder how much progress countries will make before a big outbreak of an infectious disease.

How much air do we need to open our classrooms? A hygienist’s advice on improving classroom ventilation in the wake of COVID-19

At the Harvard T.H. Chan School of Public Health, Joseph Allen is a building hygienist. He says that you can’t tell people how much air to bring in.

Allen was the first to give a number on how much of a difference it would make. In June 2020 he and his colleagues recommended that schools change the air in their classrooms in four to six hours, in case they need to open their doors after a lock down. A rate of 10–14 litres per second per person is what that amounts to. The majority of the schools achieved less than that. The study found that most California classrooms failed to meet that level of Ventilation. The WHO issued its own guidelines in March 2021, recommending a ventilation rate of 10 litres per second per person outside health-care settings.

The ability to gather real-world data to see whether low vent rates were associated with an outbreak and the ability to test different rates resulted from the P.Y. epidemic. Health officials rarely looked at ventilation when looking into major outbreak of COVID-19. A mechanical engineer at the University of Hong Kong, Yuguo Li, says that only a small percentage of investigations measured the air quality in the places where an outbreak occurred.

There is increasing evidence that technologies remove infectious particles from the air. One study4 explored the effectiveness of two air cleaners fitted with high-efficiency particulate absorbing (HEPA) filters, placed in a 54-square-metre conference room with a dummy that generated aerosol particles similar to those that transmit SARS-CoV-2. The cleaners reduced the aerosol exposure of three dummy participants by 65%. That is close to the reduction achieved by masking all of the dummies.

Ventilation requirements can be complicated, because they change depending on how big the space is, how many people are in it and how active they are. Some researchers would prefer to set maximum carbon dioxide concentrations. CO2 is frequently used as a proxy measure for ventilation and indoor air quality7. Because people exhale CO2 as they breathe, levels of the gas can shoot up if a space is crowded or if there is insufficient ventilation to replace the exhaled air — which might contain infectious viruses — with clean air.

ASHRAE standards have a recommended limit for CO2 of 1,000 parts per million. The research done in the 1930s shows that building occupants perception of body odour would be maintained at an acceptable level at this concentration. Since then, research has shown that when concentrations exceed 1,000 p.p.m., CO2 can cause drowsiness and can impair cognitive performance on decision-making and problem-solving tasks8.

Despite these issues, Morawska says that CO2 monitors should be widely deployed as an inexpensive, readily available tool that could be installed in every indoor space, much like smoke alarms. But displaying CO2 read-outs on its own is not enough, she adds, because it places the onus on room occupants to track air quality and decide what to do if readings are high.

Japan has had a law to regulate indoor air quality since 1970, which mandates that buildings must not exceed indoor CO2 concentrations of 1,000 p.p.m.. The law requires that air quality is assessed every two months, report results to the government, and establish a plan to fix the problem if the quality isn’t good. In the year, almost 30% of buildings exceeded the CO2 limit.

Kazukiyo Kumagai is a public-health engineer who works for the California Department of Health. “Japan is in a better condition” than the United States when it comes to indoor air quality, he says. Adopting a Japanese-style approach of regular monitoring and reporting might work elsewhere, he adds.

Allen says ASHRAE standards will make a difference even if they are not enforced. The ASHRAE standards make it harder for older buildings to meet the gold standard for indoor air quality.