- COVID-19 survives longer on plastic, glass and steal: Study
- The virus dies quicker on porous surfaces like paper and cloth: Study
- The study was published in the journal Physics of Fluids by IIT, Bombay
New Delhi: A study by Indian Institute of Technology, Bombay has found that the SARS-CoV-2 may survive on glass and plastic for a much longer duration as compared to porous surfaces. Surfaces having pores, such as, paper and clothes are more likely to make the conditions for the virus’ survival unfavourable, it suggests.
The study was published in the journal Physics of Fluids, with an aim to decode the survival of the virus on different surfaces. The researchers from IIT Bombay analysed the drying of droplets on impermeable and porous surfaces.
COVID-19 is caused by the SARS-CoV-2 virus and is transmitted through respiratory droplets. The virus-laden droplets also form fomite upon falling on a surface, which serves as a source for infection spread. The study concludes,
The novel coronavirus may survive for a far lesser time on porous surfaces such as paper and clothes than on impermeable surfaces like glass and plastic. This is because a droplet remains liquid for a much shorter time on a porous surface, making it less favourable to the survival of the virus.
Furthermore, it says that the virus can survive for four days on glass, and seven days on plastic as well as stainless steel. However, the virus survives only for three hours on paper and two days on cloth.
The author of the study, Sanghamitro Chatterjee says that the study helps in understanding the fomite transmission and the infrastructure analysis for various places amid the pandemic.
Based on the findings of our study, we are able to make certain recommendations like that the furniture in hospitals and offices, that are made of impermeable material, such as glass, stainless steel, or laminated wood, should be covered with a porous material, such as cloth. This will help reduce the risk of infection upon touching.
Moreover, even the seats in public places, such as parks, shopping malls, restaurants, and railway or airport waiting for halls, could be covered to with cloth to reduce the risk of disease spread, he says.
According to the study, 99.9 per cent of the droplet’s liquid content for both impermeable and porous surfaces is evaporated within the first few minutes. After this initial state, a microscopic thin residual liquid film remains on the exposed solid parts, where the virus can still survive. The evaporation of this remnant thin film is much faster in the case of porous surfaces as compared to impermeable surfaces.
These droplets spread due to capillary action between the liquid near the contact line and the horizontally oriented fibres on the porous surface and the void spaces in porous materials, which accelerates evaporation, the study said.
The fact that just the geometric features rather than the chemical details of the porous material make the thin-film lifetime significantly less was surprising, Mr Chatterjee explained.
His team, including Janani Srree Murallidharan, Amit Agrawal and Rajneesh Bhardwaj, all from IIT Bombay, believe that the study findings, such as the droplet’s liquid phase lifetime of approximately six hours on paper, will be particularly relevant in certain environments, like in schools and other educational institutes. Mr Agarwal said,
While this timescale is shorter than that of any permeable material, such as glass with a liquid phase lifetime of around four days, it would impact the exchange of notebooks. For example, it could come in handy when policymakers evaluate safe measures for reopening schools or the exchange of currency note transactions in retail banks. Similarly, cardboard boxes, used commonly by e-commerce companies around the world, could be deemed relatively safe, since they would inhibit the virus survival.
NDTV – Dettol Banega Swasth India campaign is an extension of the five-year-old Banega Swachh India initiative helmed by Campaign Ambassador Amitabh Bachchan. It aims to spread awareness about critical health issues facing the country. In wake of the current COVID-19 pandemic, the need for WASH (Water, Sanitation and Hygiene) is reaffirmed as handwashing is one of the ways to prevent Coronavirus infection and other diseases. The campaign highlights the importance of nutrition and healthcare for women and children to prevent maternal and child mortality, fight malnutrition, stunting, wasting, anaemia and disease prevention through vaccines. Importance of programmes like Public Distribution System (PDS), Mid-day Meal Scheme, POSHAN Abhiyan and the role of Aganwadis and ASHA workers are also covered. Only a Swachh or clean India where toilets are used and open defecation free (ODF) status achieved as part of the Swachh Bharat Abhiyan launched by Prime Minister Narendra Modi in 2014, can eradicate diseases like diahorrea and become a Swasth or healthy India. The campaign will continue to cover issues like air pollution, waste management, plastic ban, manual scavenging and sanitation workers and menstrual hygiene.