Coronavirus pandemic

Spraying disinfectant on streets can be harmful: WHO

GENEVA • Spraying disinfectant on the streets, as practised in some countries, does not eliminate the coronavirus and even poses a health risk, the World Health Organisation (WHO) has warned.

In a document on cleaning and disinfecting surfaces as part of the response to the virus, the WHO said spraying could be ineffective.

"Spraying or fumigation of outdoor spaces, such as streets or marketplaces, is... not recommended to kill the Covid-19 virus or other pathogens because disinfectant is inactivated by dirt and debris," the WHO said last Saturday.

"Even in the absence of organic matter, chemical spraying is unlikely to adequately cover all surfaces for the duration of the required contact time needed to inactivate pathogens."

The WHO said streets and pavements are not considered as "reservoirs of infection" of Covid-19, adding that spraying disinfectant, even outside, can be "dangerous for human health".

The document also stressed that spraying individuals with disinfectant is "not recommended under any circumstances".

"This could be physically and psychologically harmful and would not reduce an infected person's ability to spread the virus through droplets or contact," the document stated.

Spraying toxic chemicals on people can cause eye and skin irritation, bronchospasm and have gastrointestinal effects, it added.

The organisation also warned against the systematic spraying of disinfectant onto surfaces in indoor spaces, citing a study that has shown it to be ineffective outside direct spraying areas.

"If disinfectants are to be applied, this should be done with a cloth or wipe that has been soaked in disinfectant," it said.

The Sars-CoV-2 virus can attach itself to surfaces and objects. But no precise information is as yet available for the period which the virus remains infectious on the various surfaces.

Studies have shown that the virus can stay on several types of surfaces for several days. But these maximum durations are only theoretical because they are recorded under laboratory conditions and should be "interpreted with caution" in the real-world environment.


A version of this article appeared in the print edition of The Straits Times on May 18, 2020, with the headline 'Spraying disinfectant on streets can be harmful: WHO'. Subscribe