An article in The Times newspaper this week recommended the use of paper towels over hand dryers, summarising that a recent study had found this was the more hygienic way for people to dry their hands.

The report, which was funded by the European Tissue Symposium, has a number of discussion points which we will examine further, but firstly, it is important to note, that both hand drying methods were found to significantly reduce bacteria – 99% for hand dryers and 99.9% for paper towels.

The study tests the effectiveness of the two drying methods on subjects with contaminated hands. In a controlled environment the hand dryers were used for an average of 12 seconds, compared with using three to five paper towels.

At Airdri, we recommend that a person using a hand dryer should do so until their hands are completely dry, or for a minimum of 12-15 seconds when using a jet dryer such as the Airdri Quantum. This is widely recognised as an industry standard to achieve thoroughly dry hands; however, different types of hand dryers will change the length of time it takes. At least two paper towels are needed to achieve the same level of dryness (and the report uses three-five) so in comparison, the user’s hands would likely have been very dry.

As wet hands spread bacteria more effectively than dry hands as outlined in this guidance from the Centers of Disease Prevention:, it does cast doubt over the fairness of the methodology of this study.

Why? Because germs can be transferred more easily to and from wet hands and surfaces.

The study also assumes that in a real-life setting, a large proportion of people do not wash their hands properly. As this study was focused on healthcare, the conclusion was widely based on the fact that even healthcare workers take short cuts when washing hands. It states that ‘a previous study’ found up to 40 per cent do not follow the recommended hand-washing procedures. However, given the level of education and current knowledge around proper handwashing practice amid the pandemic, this statistic is questionable.

During the coronavirus outbreak we have all been asked to do our bit by washing our hands regularly. The guidance should really therefore, focus on the key message: wash your hands thoroughly, then dry them properly. Not, which method works best on poorly washed hands.

Another overlooked consideration is the “hidden bacteria” on dispenser machines and paper towels left in the bathroom:

According to research conducted by microbiologist Charles Gerba, of the University of Arizona, the average toilet paper dispenser has more than 150 times the number of bacteria than the average toilet seat. The picture isn’t much improved when it comes to paper towel dispensers. These were found to have over 50 times more bacteria on average than a typical public restroom toilet seat.

A summary of this study can be found here:

Any paper towels discarded in the bin would need to be disposed of correctly to prevent further cross contamination.

There have over the years been numerous studies into which method is most hygienic, many with conflicting results. In 2020, the Journal of Applied Microbiology completed a critical review of all existing literature on the topic and found that:

“Some studies showed a statistically significant reduction of contaminants within certain scenarios but not all ‐ whether studies involved large sample sizes or were small pilot studies, the differences between drying methods were not consistently clear. Many studies reported no statistical significance and used either low concentrations representing low‐risk scenarios or high concentrations that are not representative of pathogen levels on hands or bathroom surfaces.

The subsequent write up can be found here: and it concluded that ‘the breadth of scientific data does not support a uniform conclusion as to which drying method is safer or more hygienic’.

Finally, and an extremely important point, the study failed to evaluate the cost or environmental impact of either method.

Based on 200 uses per day, 365 days per year – an Airdri Quantum hand dryer will cost 2p per day to run, or £7 per year, as it runs on just 200 watts.

In comparison, based on 200 uses per day and a conservative estimate of two paper towels per use, the cost would be around £8 per day (based on a paper towel cost of 2p each) and £2,920 annually.

And there is little good news for the environment too as paper towels must be sent to landfill. We calculate based on 400 paper towels being used per day over a year, each weighing two grams, a total of 292,000 grams of waste is generated per day – that’s 292 kilos per year sent to landfill.

In addition to this:

Paper towels are one of the biggest causes of blocked drains

Paper towels in landfill are contributing to global warming. In the USA some 6,500,000 tonnes of paper towels are sent to landfills each year, often in plastic bags. The decay of paper products and landfills in general produces methane gas which is 28 times more potent than carbon dioxide. You can read more on the subject here:

Tony Wall, CEO of Airdri concluded:

“Where Airdri welcomes any new scientific data on this subject, the main take away from this study for us, is one of don’t mix the message. In the current climate, the focus should not be on which method is more hygienic for poorly washed hands – but to reinforce the message that people should be washing and drying their hands properly to stop the spread of viruses.

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