One common question that people ask is, how does a cycling mask compare with a surgical mask at blocking particulate matter?
This is a difficult question, and depends on a couple of important variables:
- What is it you are trying to block
- How good is the fit of the mask (are you wearing it properly)
A notable study was conducted by a team at the University of Edinburgh that looked at this in detail, comparing how cycling and surgery masks fared at blocking air pollution.
What were the masks trying to block?
In this study, the scientists looked at the effectiveness of a range of masks at blocking pollution particulate matter. The scientists used a diesel generator to simulate car exhaust, piping the exhaust directly through the mask to assess the penetration rate (i.e. the % of particles that made it through the mask).
The particles that they assessed were as small as 0.007 micrometres (microns). For context, a PM2.5 mask is designed to block any particulate matter equal or great than 2.5 microns (i.e. 3% of the diametre of a strand of hair). Therefore, for a cycling mask rated PM2.5, they were essentially checking how well a cycling mask could block particles 357 times smaller than what the mask is designed to block against.
For further context, when one coughs, respiratory droplets larger than 5 microns are released within 1-2 metres, while smaller droplet particles less than 5 microns can remain airbone for longer distances and periods if the room is enclosed and not ventilated.
How good is the fit of the mask?
For the test involving a diesel generator, the study did not obviously fit the mask on a human being. Therefore the results of the study assumes that one fits the mask perfectly as prescribed by the manufacturer.
The study did supplement the diesel generator test with a test involving human beings. They tested 15 subjects, wearing a highly efficient respiratory mask at all times outside, including a 2 hour walk within the city centre of Beijing. The results showed significantly reduced exposure to air particulate matter, leading to reduction in blood pressure and incidence of acute cardiovascular events.
The studies also found that subjects can get used to wearing the masks, while they did report slightly greater difficulty breathing, overall it did not reduce the level of exercise conducted by the subjects. This shows that it is possible to “train” people to not only wear the mask with the correct fit, but for prolonged periods as well.
In terms of the diesel generator test, the scientists found that most forms of masks did a surprisingly good job at blocking tiny particulate matter, even those below 2.5 microns. See chart below.
Only 20% of particulate matter was able to penetrate the humble surgical mask, meaning that it was effective at blocking 80% of tiny particular matter below 2.5 microns. Cycling masks were generally more effective than surgical masks. Three of the cycling masks tested blocked 85%-88% of particulate matter, outperforming the surgical mask. This is not surprising as a cycling mask is pm2.5 rated and fully wraps around tightly compared to a surgical masks, which is exposed in a number of areas. There was an outlier in terms of Cycling Mask C, which was only able to block 55% of particulates. Unfortunately, we are not able to confirm the specification of Mask C. The best performing mask were the dust respiratory masks, which are able to block 97-99% of particulate matter. However, these are also the most uncomfortable masks to wear for a prolonged period of time.
Combining the two masks
Some users have also asked if combining a surgical mask with a cycling mask would further increase the ability to capture particulate matter. No studies have looked at this in detail but having a mask over the surgical mask can extend the life of a single use surgical mask and may considered in situations where your riding is not particularly intense and you would like to have the additional peace of mind that the additional masks brings you. However, if your priority is to protect yourself from particulate matter and you do not mind the discomfort, you should probably just use a N95 or N99 respiratory mask.
A scientific comparison between a cycling mask and a surgical mask appears to show that in general, cycling masks are more effective than surgery masks at filtering particulate matter, which is not wholly surprising as that is the main function of a cycling mask. The surgical mask however was surprisingly effectively at filtering particulate matter itself.
For cycling masks at Craft Cadence, check out our range of sports masks
For our reusable cotton mask with a pocket to insert and extend the life of your surgery mask, check out Tasca (surgery mask not included).
Cover photo credit: danielkirsch / Pixabay