Surgical Masks or N95 Masks ?

It is the end of 2020 and we again face an air quality problem in Bangkok. No relevant measures have been taken to prevent poor air quality, and it seems lack of winds are to blame. Of course, this happens while Thailand is still under the spell of the Covid-19 pandemic. The number of local cases is limited. We I write this, there have been a total of 60 deaths related to Covid-19, and a total of about 4,200 infections caused by the virus. Nevertheless, there is just at this moment some concern, because of a number of infections in the Northern provinces, with some cases imported from neighboring Myanmar (some illegal border crossings).

As a result people after many months of a rather controlled situation, are still wearing masks, not only at supermarkets or while shopping, but also while walking in the street. It seems Thais are already ready to wear masks for the rest of their lives. In any case, wearing a mask, whether a dedicated one for high 2.5 PM particles, or a 'simple' surgical mask, are helpful in coping with the poor air quality at present.

Standard surgical masks and N95 mask, as available in Bangkok

Surgical Masks (left) and N95 (for 2.5 PM particle filtering) mask. Both available in Bangkok.

When looking just a bit into the matter, we were somewhat surprised to find that your standard surgical mask, is actually reasonably effective in protecting agains air pollution. Scientific fit tests and particle penetration tests find that surgical masks as cheap as a few Thai Baht block between 60-90% of particles. ( read more here ). The well known N95 masks from 3M do a better job, and seem to be indeed filtering mostly 95 % and more particles. Hopefully N95 masks as the one pictured above, and sold in Thailand (the brand pictures is produced in Thailand), do an equally good job.

It is a somewhat reassuring that standard surgical masks can be used, since N95 are not always readily available (we do not see 3M masks anymore, up to the beginning of this year, they were available at Homepro, costing a bit more than 100 baht)

As for N95 masks, it seems safe to keep on using them for a while. There seems to be no need to throw them away after one or a few days. While they remain effective for some time, you will notice that breathing through them becomes gradually a bit more difficult. Better to start using a new one, when you notice this. It likely is not healthy to face resistance in air flow while breathing. It is also worthwhile to check the working of the expiration valves. When facing a feeling of more laborious expiration, we found thath the valve on the N95 mask we were using (the one pictures above actually) did not budge, unless when forcefully blowing right into it. When we checked one of our old 3M masks, we still had lying around (at a time when maybe masks would become scarce), we noticed that the valve was working much more smoothly. Something to watch out for, when buying new supply. Maybe just only one mask, before buying a whole box.

What about the Covid-19 virus. When looking around the streets, most people seem to be using standard surgical masks (when you buy a box, check the quality, there seem to be different grades of surgical mask ; one box of masks I bought, mentions : economy, standard, and 'special' categories). Quite a few people use more fancy looking masks. Personally, we tried a couple of fabric made masks, but they were a disaster, and I was never able to fit them properly.

Both surgical masks and N95 are effective in capturing a lot of particles, even smaller ones than some virusses. At least with the flu virus, wearing either type of mask seems to reduce the number of infections by half.

The World Health Organization now clearly recommends the using of masks for preventing Covid-19 transmission, but also states that it must be part of a set of measures : Quote : "stay safe by taking some simple precautions, such as physical distancing, wearing a mask, keeping rooms well ventilated, avoiding crowds, cleaning your hands, and coughing into a bent elbow or tissue. Check local advice where you live and work. Do it all!"

One final note of N95 masks. They do have one valve or sometimes two valves. Inhaling is done through the fabric, while exhaling is facilitated through the one-way valve(s). It is good to realize that this way, the N95 mask protects the user, but does allow him or her to exhale virus particles into the surrounding area. For that reason, they are actually disallowed in some situations. Good to know, it is easy to understand, but personally I never realized it until a few months ago.

Advice :

Both types of masks are useful against small particles (PM2.5) and Covid-19 transmission. Personally I use an N95 mask when walking in the street, since this type is actually especially made to help in situations of air pollution, and is better at it than surgical masks. Surgical masks are a valuable alternative though, even if they only capture 60 % of particles. It is not a case of 'all or nothing'. Any reduction in inhaled small particles is beneficial.

For entering shops and supermarkets, I mainly use a surgical mask. An important advantage is that they offer less resistance to breathing, and are less noticeable to the user. N95 masks in this situation protect the user, but likely not people in close contact to him or her.

In summary, you need both types of masks in Bangkok (and Chiang Mai)