Scientists recommend at least 40% humidity in public buildings to curb COVID-19 spread
New Delhi: In addition to measures like social distancing and wearing masks, an Indian-German team of scientists recommend controlling indoor humidity conditions to contain the spread of the novel coronavirus which causes COVID-19.
The researchers, including those from CSIR National Physical Laboratory in New Delhi, said in order to contain the pandemic, it is extremely important to implement standards for indoor air humidity in rooms with many people, such as hospitals, open-plan offices, or public transport.
In their review of studies, published in the journal Aerosol and Air Quality Research, the scientists specifically drew focus on relative humidity, which is a measure of water vapour in the air compared to the total saturation of vapour that can exist in the air at its current temperature.
According to the study, a relative humidity of 40 to 60 percent could reduce the spread of viruses and their absorption through the nasal mucous membrane.
The scientists said tiny drops of five micrometres in diameter, such as those produced when speaking, can float in the air for up to nine minutes.
"In aerosol research, it has long been known that air humidity plays a major role -- The more humid the air is, the more water adheres to the particles and so they can grow faster. So, we were curious -- what studies have already been conducted on this," explained Ajit Ahlawat, a co-author of the study from the Leibniz Institute for Tropospheric Research (TROPOS) in Germany.
According to the scientists, humidity affects the behaviour of microorganisms within the virus droplets, and the survival or inactivation of the virus on the surfaces.
They said it also influences the role of dry indoor air in the airborne transmission of viruses.
"If the relative humidity of indoor air is below 40 per cent, the particles emitted by infected people absorb less water, remain lighter, fly further through the room and are more likely to be inhaled by healthy people," Ahlawat explained.
"In addition, dry air also makes the mucous membranes in our noses dry and more permeable to viruses," he said.
The scientists believe the new findings are particularly important for the upcoming winter season in the northern hemisphere, when millions of people will be staying in heated rooms.
"Heating the fresh air also ensures that it dries. In cold and temperate climate zones, therefore, the indoor climate is usually very dry during the heating season. This could encourage the spread of coronaviruses," said study co-author Alfred Wiedensohler of TROPOS.
At a higher humidity, the scientists said droplets grow faster, fall to the ground earlier, and can be inhaled less by healthy people.
"A humidity level of at least 40 per cent in public buildings and local transport would therefore not only reduce the effects of COVID-19, but also of other viral diseases such as seasonal flu. Authorities should include the humidity factor in future indoor guidelines," added study co-author Sumit Kumar Mishra of CSIR - National Physical Laboratory in New Delhi.
For countries in cool climates, the scientists recommend a minimum indoor humidity.
They said countries in tropical and hot climates, on the other hand, should take care that indoor rooms are not extremely undercooled by air conditioning systems.
When air is extremely cooled, it dries out the air and the particles in it, making people inside the room feel comfortable, but the dry particles will remain in the air for longer duration, the researchers warned.
They added that the measures already known, such as social distancing, having as few people per room as possible, and wearing masks should also be practised to lower the risk of infection.
Let the Truth be known. If you read VB and like VB, please be a VB Supporter and Help us deliver the Truth to one and all.
Inappropriate for MLAs seeking free IPL tickets, says D.K. Suresh
Bengaluru: Bengaluru Milk Union Ltd President D.K. Suresh on Monday said it is inappropriate for MLAs to seek free IPL tickets, adding that those interested in watching matches should pay for them personally.
Speaking to reporters near his residence in Sadashivanagar, he said, “IPL is a commercial tournament and does not represent the country. It is not right for public representatives to focus too much on such matters.”
Referring to the recent controversy during the RCB celebrations, he said, “let us find out who benefited the most from the statements made during the incident.” He also pointed out that BJP MLAs had received IPL tickets as well.
Responding to discussions about relocating the Chinnaswamy Stadium, Suresh said the government has already approved the construction of a new stadium at a location he had proposed.
“I had suggested building a stadium in Surya City and submitted a proposal for it. Bengaluru needs four stadiums in four directions to cater to its growing population and encourage youth participation in sports,” he said.
He noted that apart from Kanteerava Stadium, KSCA, and the Football Stadium, there are limited facilities in the city.
“When I was a Lok Sabha member, I had proposed allocating 100 acres in my constituency at Surya City. The land was later earmarked and the plan approved,” he added.
Suresh said he has discussed the project with Minister Zameer Ahmed Khan, Rajiv Gandhi Housing Corporation Chairman Shivalingegowda, and Anekal MLA Shivanna.
“The Cabinet has now approved the project, and a stadium will be developed on around 50–60 acres,” he said.
He further added that he has requested the Deputy Chief Minister to build another stadium at Shivarama Karanth Layout through the BDA, where 40 acres have been allocated. Plans are also being discussed to develop a well-equipped stadium in Bidadi.
Commending state government's recent bilingual policy move, Suresh said forcing children to learn three languages could affect their comprehension.
“It is a good decision to make two languages compulsory. Learning a third language should be left to the choice of students and parents,” he said.
Responding to criticism from BJP leaders, he said their tendency is to oppose every decision of the government.
“To please their central leadership, they take a pro-Hindi stance. Instead, they should advocate for the adoption of Kannada in all states,” he said.
When asked about the earlier three-language policy under Congress, he said, “the situation is different now. Today, the focus should be on quality learning. Kannada should remain the primary language, while students and parents can choose an additional language.”
