Coronavirus airborne: What we should do now

International New York Times
July 7, 2020

The coronavirus can stay aloft for hours in tiny droplets in stagnant air, infecting people as they inhale, mounting scientific evidence suggests.

This risk is highest in crowded indoor spaces with poor ventilation, and may help explain superspreading events reported in meatpacking plants, churches and restaurants.

It’s unclear how often the virus is spread via these tiny droplets, or aerosols, compared with larger droplets that are expelled when a sick person coughs or sneezes, or transmitted through contact with contaminated surfaces, said Linsey Marr, an aerosol expert at Virginia Tech.

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Aerosols are released even when a person without symptoms exhales, talks or sings, according to Marr and more than 200 other experts, who have outlined the evidence in an open letter to the World Health Organization.

What is clear, they said, is that people should consider minimizing time indoors with people outside their families. Schools, nursing homes and businesses should consider adding powerful new air filters and ultraviolet lights that can kill airborne viruses.

What does it mean for a virus to be airborne?

For a virus to be airborne means that it can be carried through the air in a viable form. For most pathogens, this is a yes-no scenario. HIV, too delicate to survive outside the body, is not airborne. Measles is airborne, and dangerously so: It can survive in the air for up to two hours.

For the coronavirus, the definition has been more complicated. Experts agree that the virus does not travel long distances or remain viable outdoors. But evidence suggests it can traverse the length of a room and, in one set of experimental conditions, remain viable for perhaps three hours.

How are aerosols different from droplets?

Aerosols are droplets, droplets are aerosols — they do not differ except in size. Scientists sometimes refer to droplets fewer than 5 microns in diameter as aerosols. (By comparison, a red blood cell is about 5 microns in diameter; a human hair is about 50 microns wide.)

From the start of the pandemic, the WHO and other public health organizations have focused on the virus’s ability to spread through large droplets that are expelled when a symptomatic person coughs or sneezes.

These droplets are heavy, relatively speaking, and fall quickly to the floor or onto a surface that others might touch. This is why public health agencies have recommended maintaining a distance of at least 6 feet from others, and frequent hand washing.

But some experts have said for months that infected people also are releasing aerosols when they cough and sneeze. More important, they expel aerosols even when they breathe, talk or sing, especially with some exertion.

Scientists know now that people can spread the virus even in the absence of symptoms — without coughing or sneezing — and aerosols might explain that phenomenon.

Because aerosols are smaller, they contain much less virus than droplets do. But because they are lighter, they can linger in the air for hours, especially in the absence of fresh air. In a crowded indoor space, a single infected person can release enough aerosolized virus over time to infect many people, perhaps seeding a superspreader event.

For droplets to be responsible for that kind of spread, a single person would have to be within a few feet of all the other people, or to have contaminated an object that everyone else touched. All that seems unlikely to many experts: “I have to do too many mental gymnastics to explain those other routes of transmission compared to aerosol transmission, which is much simpler,” Marr said.

Can I stop worrying about physical distancing and washing my hands?

Physical distancing is still very important. The closer you are to an infected person, the more aerosols and droplets you may be exposed to. Washing your hands often is still a good idea.

What’s new is that those two things may not be enough. “We should be placing as much emphasis on masks and ventilation as we do with hand washing,” Marr said. “As far as we can tell, this is equally important, if not more important.”

Should I begin wearing a hospital-grade mask indoors? And how long is too long to stay indoors?

Health care workers may all need to wear N95 masks, which filter out most aerosols. At the moment, they are advised to do so only when engaged in certain medical procedures that are thought to produce aerosols.

For the rest of us, cloth face masks will still greatly reduce risk, as long as most people wear them. At home, when you’re with your own family or with roommates you know to be careful, masks are still not necessary. But it is a good idea to wear them in other indoor spaces, experts said.

As for how long is safe, that is frustratingly tough to answer. A lot depends on whether the room is too crowded to allow for a safe distance from others and whether there is fresh air circulating through the room.

What does airborne transmission mean for reopening schools and colleges?

This is a matter of intense debate. Many schools are poorly ventilated and are too poorly funded to invest in new filtration systems. “There is a huge vulnerability to infection transmission via aerosols in schools,” said Don Milton, an aerosol expert at the University of Maryland.

Most children younger than 12 seem to have only mild symptoms, if any, so elementary schools may get by. “So far, we don’t have evidence that elementary schools will be a problem, but the upper grades, I think, would be more likely to be a problem,” Milton said.

College dorms and classrooms are also cause for concern.

Milton said the government should think of long-term solutions for these problems. Having public schools closed “clogs up the whole economy, and it’s a major vulnerability,” he said.

“Until we understand how this is part of our national defense, and fund it appropriately, we’re going to remain extremely vulnerable to these kinds of biological threats.”

What are some things I can do to minimize the risks?

Do as much as you can outdoors. Despite the many photos of people at beaches, even a somewhat crowded beach, especially on a breezy day, is likely to be safer than a pub or an indoor restaurant with recycled air.

But even outdoors, wear a mask if you are likely to be close to others for an extended period.

When indoors, one simple thing people can do is to “open their windows and doors whenever possible,” Marr said. You can also upgrade the filters in your home air-conditioning systems, or adjust the settings to use more outdoor air rather than recirculated air.

Public buildings and businesses may want to invest in air purifiers and ultraviolet lights that can kill the virus. Despite their reputation, elevators may not be a big risk, Milton said, compared with public bathrooms or offices with stagnant air where you may spend a long time.

If none of those things are possible, try to minimize the time you spend in an indoor space, especially without a mask. The longer you spend inside, the greater the dose of virus you might inhale.

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News Network
March 2,2020

Mathura, Mar 2: Union Minister of state Sadhvi Niranjan Jyoti on Sunday said after the Citizenship (Amendment) Act (CAA), the Centre might bring a population control law.

Jyoti claimed that she has already spoken to Prime Minister Narendra Modi in this regard.

She said she believes that this issue is under the prime minister's consideration and he himself has discussed the importance of bringing this law.

Jyoti arrived here on Sunday to attend a tribute meeting held at Swami Vamdev Jyotirmath in Chaitanya Vihar. Unnao MP Sakshi Maharaj was also present at the event.

"There was a time when abrogation of Article 370 in Jammu and Kashmir was impossible. It was feared that if such thing happens, there will be bloodbath. No one will be hold the national flag in Kashmir. But this government can bring any law in favour of the nation," Jyoti said.

"Now, everyone believes that if Article 370 can be removed...Prime Minister Narendra Modi can bring any law which is important for the country," she added.

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expat
 - 
Monday, 2 Mar 2020

already people are childless. struggling for IVF treatment. no need of population control. it is automatically getting control byu nature.

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Agencies
March 14,2020

New Delhi, Mar 14: Excise duty on petrol and diesel was on Saturday hiked by ₹3 per litre as the government looked to mop up gains arising from fall in international oil prices.

Special excise duty on petrol was hiked by ₹2 to ₹8 per litre incase of petrol and to Rs 4 incase of diesel, an official notification said.

Additionally, road cess on petrol was raised by ₹1 per litre each on petrol and diesel to ₹10.

The increase in excise duty would in normal course result in a hike in petrol and diesel prices but most of it would be adjusted against the fall in rates that would have necessitated because of slump in international oil prices.

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News Network
February 2,2020

New Delhi, Feb 2: The Congress on Sunday released its manifesto for Delhi polls, promising to implement unemployment allowance of Rs 5,000-7,500 per month and cashback schemes for water and power consumers, if voted to power.

Presenting the manifesto, Delhi Congress chief Subhash Chopra said the party will provide free power up to 300 unit per month.

The manifesto also committed to spend 25 per cent budget each year on fighting pollution and improving transport facilities.

An unemployment allowance of Rs 5,000 for graduates and Rs 7,500 for post graduates per month will be provided under the Yuva Swabhiman Yojna, he said.

The Congress will launch flagship cashback schemes for power and water supply to benefit consumers saving these resources. The party, if voted to power, will open 100 Indira Canteens to provide subsidised meals at Rs 15, Chopra said.

The Congress will challenge the Citizenship Amendment Act (CAA) in the Supreme Court and demand the Centre to withdraw the law. The party will also not implement the National Register of Citizens (NRC) and the existing form of the National Population Register (NPR), if voted to power in Delhi.

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