• Many cities are disinfecting public surfaces with bleach-and-water mixtures.
  • Experts aren't sure how long the contagious virus can live on surfaces, but say it could range from a few hours to a day or so.
  • Spraying disinfectant solutions into the air is probably not an effective way to kill the virus, but wiping down highly touched surfaces is.
  • Photos show mosques, schools, and streets being sprayed and wiped down around the world.
  • Visit Business Insider's homepage for more stories .

One of the most effective ways to fight the spread of the new coronavirus is to disinfect highly touched surfaces. Across the world, disinfection teams have descended upon kindergartens, state capital buildings, markets, mosques, airports, and public roads.

Teams of hazmat-suited workers are spraying low-concentration bleach-and-water mixtures from trucks, guns, drones, and robots.

Public-health experts think mass disinfection efforts will have mixed effectiveness in outbreak zones. Disinfecting surfaces that are commonly touched, such as in hospitals, schools, and religious sites, can help kill germs. However, misting sanitizer in the air or on the street is likely ineffective, because the virus isn't airborne and people don't touch the street that often.

The coronavirus has spread to more than 90 countries since it emerged in Wuhan, China, late last year. In total, at least 100,000 people have been infected, and more than 3,400 have died. (See Business Insider's latest updates here .)

Photos from China, South Korea, Iran, Iraq, Russia, Nigeria, and more show how the world is trying to sanitize.

China has placed around 56 million people under quarantine. Public gatherings are banned, schools are shut down, and employees are working from home if possible.

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Thomas Peter/Reuters

The city of Wuhan, where the outbreak began, has been quarantined since January 23 . Transportation buses, subways, ferries, trains, airplanes, and private cars has been halted.

In cities and towns across China, including Shanghai, Beijing, and Wuhan, sanitation workers have been sent to spray down all public areas. Trucks filled with low-concentration bleach-and-water solutions drive through the streets.

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China Daily via Reuters

Source: Business Insider .

Workers wearing hazmat suits and face masks have swept through train stations, malls, and other destinations, wiping down surfaces to kill viral particles that might linger on them.

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Aly Song/Reuters

Scientists aren't yet sure how long droplets containing the virus can live on surfaces. According to the World Health Organization, "studies suggest that coronaviruses (including preliminary information on the COVID-19 virus) may persist on surfaces for a few hours or up to several days."

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China Daily via Reuters

The wide range depends on factors like the type of surface a droplet lands on, the temperature or humidity of the surrounding environment, and what kind of droplet a virus is traveling in (saliva or phlegm, say).

But sanitizing misters are probably not the most effective way to kill the virus, experts say. The coronavirus mainly travels person to person through saliva and mucus droplets, not through tiny particles in the air.

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China News Service via Reuters

When people who have COVID-19, the disease caused by the coronavirus, cough and sneeze, the viral particles can land on those within 3 to 5 feet and infect them.

"I would rather see better efforts to make sure people are disinfecting emergency rooms and high-touch surfaces in hospitals and schools more than I would want to see bleach being sprayed on streets," Saskia Popescu, an infection-prevention epidemiologist, told Business Insider.

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China Daily via Reuters

"Honestly, think about how often do your hands or your mouth come into contact with a street?" she said .

China also uses spray cannons similar to the ones used for disinfection to combat smog: Industrial misters can spray water droplets that trap and pull dust and pollution particles out of the air in smoggy areas.

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China Daily via Reuters

Source: China Dialogue.

Experts stress that basic public-health measures like washing your hands, avoiding touching your face, and staying away from sick people are the best ways to protect yourself.

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China Daily via Reuters

Cases of coronavirus are spiking in South Korea: More than 6,500 people have been infected.

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Heo Ran/Reuters

In South Korea, the virus has spread among a religious group called the Shincheonji Church of Jesus in the city of Daegu, the country's fourth-largest city.

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Yonhap via Reuters

A 61-year-old churchgoer in Daegu tested positive and caused a "super-spreader" event: Over two weekends at tightly packed prayer services, she came in contact with over 1,000 people.

The South Korean government has canceled and postponed public gatherings.

Moon Jae-in, South Korea's president,said in a cabinet meeting on Tuesdaythat the "entire nation has entered a state of war against this infectious disease."

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Yonhap via Reuters

After the country's National Assembly met about its coronavirus response, a sanitation team disinfected the space.

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Yonhap via Reuters

Disinfectant products like hand sanitizer are selling out in South Korea, according to Reuters. With soaring demand for ethanol to produce more disinfectant, South Korean soju makers have donated the alcohol that typically goes into the drink.

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Woohae Cho/Getty Images

Source: Reuters

Italy has reported more than 140 coronavirus deaths the highest number outside of China. The two major outbreak zones are near Milan and Venice.

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Stefano Mazzola/Awakening via Getty Images

The Italian government has called for the cancelation of any event that would be too crowded for people to stay at least 3 feet away from others. Schools and universities have been closed for more than a week.

In Nigeria, an Italian man tested positive for coronavirus after arriving in Lagos from Milan on February 24. He was diagnosed three days later after developing symptoms. It was the first confirmed case of the coronavirus in sub-Saharan Africa.

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Pius Utomi Ekpei/AFP via Getty Images

The Government of Nigeria has established a "coronavirus preparedness group," led by its Center for Disease Control. The World Health Organization also said that it already has experts on the ground in Nigeria, which it calls a "high priority" country.

Iran has over 4,700 coronavirus cases and 124 deaths the second-highest number of deaths in countries outside China (after Italy).

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WANA (West Asia News Agency) via Reuters

About 8% of Iran's parliament 23 out of 290 members is affected by the coronavirus. The country preemptively released 54,000 prisoners to avoid the disease's spread in its crowded prisons.

Trucks filled with disinfectants are spraying down streets, shrines, public parks, trash bins, public toilets, and markets in Tehran and other areas with rising case totals, Reuters reported.

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WANA (West Asia News Agency) via Reuters

Sanitation teams are also disinfecting religious sites in Iran, but those have not been closed or locked down.

"The smell of disinfectants has become my nightmare," Ziba Rezaie, a 62-year-old retired teacher from Qom, Iran, told Reuters. "The city smells like a cemetery, a morgue."

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WANA (West Asia News Agency) via Reuters

Source: Reuters .

Iran and Iraq share a border, and residents frequently cross for religious, medical, and business visits. Iraq has reported at least 40 cases.

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Alaa al-Marjani/Reuters

The majority of these patients are Iraqis who recently visited Iran.

The Iraqi government has closed the border with Iran. Authorities have also ordered schools, universities, theaters, restaurants, and other public places to shut down.

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Haidar Hamdani/AFP via Getty Images

The virus is now in at least 90 countries other than China.

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Nhac Nguyen/AFP via Getty Images

Vietnam had 16 confirmed cases, but all the patients have recovered. The country closed its borders with China and closed public schools, according to reports from local media .

Some schools in Lebanon have closed as well.

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Ali Hashisho/Reuters

Source: Reuters .

The country of Georgia reported its first case of coronavirus on February 26. Georgian health minister Ekaterine Tikaradze said the citizen traveled to and from Iran.

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Irakli Gedenidze/Reuters

The country has suspended travel between Georgia and Iran for two weeks. Travel to China is also banned.

Russia has stepped up sanitation efforts. It has also closed most entry points along its 4,200-kilometer border with China and temporarily banned Chinese citizens from entering the country.

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Mikhail Tereshchenko/TASS via Getty Images

The World Health Organization increased the global risk of the new coronavirus to "very high" on Monday. The organization's director-general, Tedros Adhanom Ghebreyesus, said at a briefing Tuesday that containment of the virus is still possible.

Hilary Brueck contributed reporting.

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SEE ALSO: Photos show why hand sanitizer doesn't work as well as soap and water to remove germs