On looking at the prices of masks and filters, I figured that it could eventually get rather expensive for me. Moreover, there's an article in a newspaper that these masks don't really help:

Don't be fooled by safety masks (Sep 30, 2001)
According to a two-year painstaking study conducted by a group of researchers in the department of chemical engineering, Indian Institute of Science, no mask being sold in Bangalore is effective against the most common and harmful pollutants: carbon monoxide (co), sulphur dioxide (so2), suspended particulate matter (spm), oxides of nitrogen (nox). The study, commissioned by the council for scientific and industrial research (csir), has been examining all the material used in the filters inside the plastic masks. To their utter dismay, researchers found that people using these masks are being fooled beyond imagination. says senior scientific officer Mr.J.R. Mudakavi: "we have tested more than a dozen such masks available in the city's markets. I am sorry to see that none of them informs the buyer what it is effective against, what load it can take, if the filter is recyclable, et al". The most injurious of all, CO, is not filtered by any mask. sulphur dioxide is absorbed by some filters to some extent, but given its concentration in the atmosphere, these masks are effective only for 2-3 hours. no user is told that if the filter is washed it can be used efficaciously a few more times. one of the dreaded pollutants is spm (small particles from industry, stone crushing, construction materials, exhaust, etc) which when inhaled in large quantity gets deposited in the lungs and can cause silicosis.

Ok, so if even the anti-pollution masks can't filter out CO or SO2 properly, then that leaves the danger of the particulate matter which in my opinion, could be prevented with just a cloth wrapped around the nose and mouth.

Not a thin layer of cloth. A cloth where the folds form a couple of layers over your face and nose. If this cloth is moistened a bit, shouldn't it be effective against particulate matter.

For a short ride of maybe 30 minutes, won't a simple cloth be more cost effective and offer a reasonable amount of protection against pollutants?

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    It would probably be about as bad as most of the masks, even expensive ones. Many of the particulates are rather small and a mask that allows you to breathe hard while filtering them out properly needs to be well engineered and very close fitting (basically useless with facial hair for example).
    – Chris H
    Commented Dec 22, 2015 at 17:45
  • The cloth will do almost nothing. The question you need to answer is whether you want "better than nothing" or more, and what you're willing or able to spend. Better masks will have reusable filters but the filters are still a consumable and they generally don't have a useful wear indicator. My welding filters (multiple types depending on what I most want to filter out) are rated for X hours at Y airflow, and I just have to throw them out after X hours because there's no way to tell when they stop working. Road masks will be the same, wear it one day, wash it, reuse it, throw it out.
    – Móż
    Commented Dec 22, 2015 at 21:00
  • @Mσᶎ Nothing? Cloth will filter any particle bigger than the pours in the cloth. Have you ever driven cattle? If you get hit with tear gas the yes pull your shirt (and jacket) up over you face will help. And don't weld on a bicycle.
    – paparazzo
    Commented Dec 22, 2015 at 21:39
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    The problem is that you can't ride very well with most masks/respirators (even a regular n95 mask, which doesn't do anything for CO and stuff). They're very difficult to breathe with. Read this article from OSHA.
    – Batman
    Commented Dec 22, 2015 at 22:20
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    Despite what I said before, it should be noted that a dampened cloth will have a modest effectiveness against SO2, since SO2 dissolves readily in water. Whether this would amount to reducing SO2 by 90% or only 0.9%, though, I can't say. A more effective mask could probably be made by including some other chemical with the water, but I don't know what that would be, and the chemical would likely have its own safety issues as well. (CO is also soluble in water, but less so.) Commented Dec 28, 2015 at 17:54

3 Answers 3


that leaves the danger of the particulate matter which in my opinion, could be prevented with just a cloth wrapped around the nose and mouth.

Diesel particulates are mostly in the 3-30 nanometre range of sizes. This is very fine and will not be stopped by normal cloth.

3M say a P2 (EU rating) filter should reduce exposure to diesel particulates. A P3 mask should remove a higher proportion of particles. I suspect these filters might not remove the finer diesel particulates.

Most of these masks are not intended to supply a large volume of air, they are workplace masks not sports masks.

Some cycling mask makers write about PM10 filtering. Note that PM10 are coarse dust particles 2500 to 10000 nanometers in size. That's a lot larger than most diesel particulates.

The key to an effective filter is a good air-tight closure against the skin around the entire perimeter of the filter. You cannot obtain the necessary fit using cloth alone.

If anecdotal stories have anything to teach it is that you should expect a white filter to become blackened even on short rides and that you therefore need to replace the filter every ride.

  • my experience was similar to that, even using the respro. You just have to budget for a new set of filters every day or to, and buy them accordingly. Respro don't sell 100 packs of filters.
    – Móż
    Commented Dec 28, 2015 at 0:20


The typical "pollution mask" I have seen are modified or styled after surgical masks. Surgical masks are NOT designed to filter intake air. They are designed to direct exhaust air away from a patient who is opened up and vulnerable to infection. The masks shown on your links appear to have possibly a sealing face mask, but the filters look clearly inadequate.

To properly filter air, you will need a mask that seals around your mouth and nose and has a proper one way valve(es) and appropriate filters. Interior Alaska has some of the poorest air quality in the world during both the winter (inversion layer) and summer (forest fires) months. What I have taken to using are the rather inexpensive "paint style" masks that 3M and other companies make that are available from home improvement stores like Home Depot. The masks are rated for organic vapors and have replaceable filters, although I find it easier to simply replace the whole mask.

As for the difficulty breathing in these masks, I find that I cannot get enough air through them to maintain a full sprint, however, I can get enough to maintain a "race pace". After a bit of use, I get even less air, or I can change the prefilters and filters and get back to where I started.

  • So the ordinary masks which are designed so stylishly and advertised so well, are just a farce! It's sad that we have to use something like a paint style mask for cycling. It's even more sad that the problem could've been solved in 1996, but was killed: youtube.com/watch?v=nsJAlrYjGz8
    – Nav
    Commented Dec 28, 2015 at 17:08
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    Your link is unrelated. Forest fires are a naturally occurring part of the ecology in the subarctic landscape. The "fire zone" of midnorthern Alaska has more acreage on fire any given summer than the rest of the lower 48 combined. The result smoke pools in calmer bowl type areas like the valley that Fairbanks lays in. latimes.com/nation/la-na-western-wildfires-20150817-story.html Commented Dec 28, 2015 at 17:30
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    Electric cars partly solve one part of the problem. Trucks, stationary energy plants (especially coal) and residential burning are a bigger problem. Finding a mask that's both effective and affordable is hard, as Sus User says. I've tried a powered mask and that was better, but it wasn't designed to provide airflow for a sprint. And it cost a lot.
    – Nuі
    Commented Dec 28, 2015 at 19:56
  • @SuspendedUser: Agreed, there are natural sources of pollution. All I'm saying is that it's silly that we have to wear masks when we had found ways of keeping the air clean in the 90's itself.
    – Nav
    Commented Dec 29, 2015 at 15:53
  • @Nav I have never worn a respirator to filter out anthropogenic pollution. Even if every car on the road was electric, I'd still have to wear a respirator for weeks every summer when the forest fires start. Commented Dec 30, 2015 at 18:37

I don't think I would make decisions based on masks available in the city markets of Bangalore.

You need to decide what is reasonable for you. A cloth is not going to be as effective as a mask designed for particulate matter (and other pollutants). Cloth will only get large particles and nothing for other pollutants. But large particle is better than no particles. On a dusty trail most particles are large. If you get 40% that is still 40%.

As for CO and SO2. If there is source (delivering dangerous levels) of CO or SO2 then don't ride there.

If there are pollutants in your area then what about the 23 1/2 hours in the day?

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    "If there is source of CO of or SO2 then don't ride there." So, no cycling on roads, then! Commented Dec 22, 2015 at 19:50
  • @DavidRicherby A source and the source is not the same. If the ROAD is producing CO or SO2 then it is the SOURCE and you should not be riding on that road. What is the chemistry by which a road produces CO or SO2? In the atmosphere and source are not the same. With any gas you will have a higher concentration near the source - avoid that source. Does that not seem prudent to you? merriam-webster.com/dictionary/source
    – paparazzo
    Commented Dec 22, 2015 at 21:20
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    The source is the motor vehicles using the road. Commented Dec 22, 2015 at 21:35
  • OK the source is cars. If it is too high then don't ride there. So you take that as any level of source? Come on man.
    – paparazzo
    Commented Dec 22, 2015 at 21:47
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    @Frisbee: the half-life for CO in the blood is about 4-6 hours, CO is a naturally occurring byproduct of metabolism in small quantities and the body has ways of dealing with it, it's not like heavy metal poisoning. Commented Dec 23, 2015 at 0:53

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