ECJ EUROPEAN Cleaning Journal

Dutch reporter John Griep on a study into whether cleaning machines actually pollute the air.

For once, this column is not about coronavirus, but about the paradoxical question of whether a cleaning machine can pollute at the same time. Although coronavirus still dominates our lives, other research continues. This includes research into the emission of micro-organisms by scrubber dryers.

You read it right: the question is whether these cleaning machines pollute the air. After all, scrubber dryers suck up contaminated cleaning fluid and then blow out the air they use to do it. It is not very far-fetched to think that the air leaving the machine could be contaminated and pollute the ambient air.

It is a theory that arose within the VSR Technical Committee, which they thought was worth investigating. The study was conducted in two phases. Initially, at five hospitals, two machines in use were examined for the degree of contamination of the liquid in the holding tank immediately after use. Substantial numbers of micro-organisms were found in all the holding tanks for these machines.

Secondly, there was an investigation into whether and to what extent micro-organisms that have ended up in the absorbed cleaning fluid are dispersed into the ambient air while cleaning with a scrubber dryer. The outgoing air was sampled during cleaning with a scrubber dryer. The tests were carried out both with and without the use of a HEPA filter. In addition, the concentration of yeast germs in the ambient air was measured before and after the tests.

The questions VSR hoped to answer are:
1. Do scrubber dryers disperse micro-organisms removed from the floor into the ambient air during operation?
2. And, if this is the case, how does this contamination relate to the amount of germs already present in the air?
3. Finally, if airborne germs are spread by scrubber dryers, is this to an extent that could cause health risks?

Germs level lower

The overall conclusion of the study was that the concentration of yeast germs in air exiting the scrubber dryer during operation was not higher before or after the tests. The concentration of germs blown out of the machine with HEPA filter during cleaning with a scrubber dryer is even lower than before and after the tests.

The answer to research question one is therefore that the scrubber dryers used for this research do not spread the micro-organisms removed from the floor into the ambient air.

The answer to research question two holds that the germ count for the outgoing air in this research was equal or, when a HEPA filter was applied, even lower than that of the incoming air. The germ concentration in the ambient air is therefore not adversely affected.

Therefore, the answer to question three is also obvious: the use of a scrubber dryer as described in this study has no influence on air hygiene. This implies that no health effects due to degraded air hygiene are to be expected for people living in the vicinity, nor for employees working with scrubber dryers.

This is good news at a time when healthy air is literally a matter of life and death!