Is the coronavirus pandemic bad news for “green” cleaning products? Caroline Hand investigates whether it is good science to put the eco-friendly cleaners away for the duration of the pandemic and head back to the bleach.

Plant-based, “natural”, kind to animals and the ecosystem ⁠— what’s not to like? Many businesses use eco-friendly cleaning products as part of their overall commitment to sustainability. As well as having a low impact on the environment, these products are known to be gentle on the skin, packaged in reusable containers and often made from recycled materials. In the past, the main question asked about these products was “do they do a good job of cleaning and disinfecting”, but now, of course, we are asking “do they kill the coronavirus?”

What’s the difference between cleaning and disinfection?

Cleaning removes dirt and grime, which harbour bacteria and viruses, while disinfection kills the micro-organisms. Both cleaning and disinfection are necessary, and some products such as bleach sprays, perform both functions.

Officially endorsed cleaning products

There is no shortage of guidance, both directly from the Government and in the national media, about the best way to clean and disinfect surfaces which should be done regularly to stop the spread of the virus: otherwise, it can survive for several days on hard surfaces such as plastic and metal. But does the choice of cleaning product make a difference?

In both the UK and USA, the Governments have issued advice on effective disinfectants.

  1. Bleach. Household bleach is sodium hypochlorite diluted in water. Householders are advised that the bleach on sale in supermarkets contains about 5% of sodium hypochlorite, and they can dilute this to 0.5% to clean hard surfaces. Bleach-based spray cleaners are already diluted so they can be used straight away.

  2. Hydrogen peroxide. This is sold as a solution of about 3% which can be used directly on surfaces.

  3. Alcohol, eg isopropyl alcohol and ethanol. Alcohol is only effective in killing the virus at concentrations over 70%; early rumours that vodka could do the job were firmly quashed. 100% alcohol should not be used as it evaporates too quickly. Hand sanitisers are alcohol-based.

  4. Soap. Traditional soap is effective in both cleaning and disinfection. Soap removes the viral particles that have attached themselves to surfaces and suspends them in the water, so they can be washed away. Moreover, it destroys the coronavirus’s fatty protective shell, causing (to quote a US website) the virus’s “guts to spill out”. Therefore, soap can be just as good as hard-to-source hand sanitiser for personal hygiene.

Can “green” products keep our workplaces safe?

As some employees return to work, businesses must take extra care to clean frequently touched surfaces such as keyboards, door handles, stair rails and toilets. Everyone will be expected to wash their hands thoroughly on arrival at their workplace, and then frequently throughout the day. Surfaces in kitchens and washrooms should be regularly cleaned, with a thorough rubbing rather than merely a quick spray or swipe, then dried with disposable cloths or paper towels — as dampness helps any remaining viruses to survive — and reusable cleaning equipment (mops, etc) should be frequently cleaned and disinfected.

An American journalist observed at the beginning of the lockdown that while the local supermarket had been cleared of almost all household cleaners and sanitisers, her favourite eco-friendly products were still sitting on the shelves. The manufacturers had not been able to add “kills 99.9% of viruses” to the labels. People have been warned that home-made cleaning products based on vinegar or bicarbonate of soda have no effect on the virus; but what about proprietary “green” products?

These products will not contain bleach, as it is generally perceived as harmful to the environment. However, some of them may contain soap. A careful look at the “small print” ingredients of two products revealed that they both contained gentle soaps. Unfortunately, it is the harsher soaps — classified as ionic — which are most effective against the virus.

In March, Santander reported that it is “reverting back to traditional disinfectant cleaning products from the green products being used today until further notice, to maximize the effect of the cleaners”.

So, for the time being, the best advice seems to be a return to bleach, peroxide and alcohol, since protecting lives from the virus must take priority.

But is bleach such a villain?

Eco-friendly products exclude bleach because it is regarded as harmful to the aquatic environment. However, the manufacturers are eager to exonerate their product of this charge. The website of US bleach manufacturer Clorox states that 95–98% of household bleach breaks down very quickly after use, the remaining 2–5% being dealt with by sewage treatment. None ends up in groundwater. They state that “household bleach begins and ends as salt water in a fully sustainable cycle”. The use of household bleach for cleaning should not be confused with the bleaching of paper products using chlorine.

There is no reason to disbelieve the manufacturers’ statements here — the concerns about bleach arise out of the wider environmental impact of the chemical manufacturing industry, and particularly the manufacture of harmful organochlorine products, rather than the behaviour of everyday household bleach.

Bleach does, however, carry some minor hazards: it can damage paint and metal if used in too high a concentration or allowed to remain too long on the surface, and the fumes can aggravate respiratory conditions such as asthma. One study indicated that if used once a week, bleach can significantly increase the risk of developing COPD (Chronic Obstructive Pulmonary Disease). Cleaners using bleach should wear gloves to protect their skin and ensure that the workplace is well ventilated.

Conclusion

During this time of record sales for cleaning products of all kinds, all is not lost for sustainable manufacturers. In the USA, the Government has issued a list of branded products that are effective in killing the coronavirus. While most of these are established brands containing bleach, peroxide or alcohol, the eco-friendly brand Seventh Generation (whose effective ingredient remains a secret) is now included on the list. Perhaps other brands will also rise to the challenge of manufacturing a product which, while effective against the virus, retains the other positive qualities of eco-friendly cleaners.

Last reviewed 7 June 2020