{"id":423,"date":"2018-11-20T07:18:44","date_gmt":"2018-11-20T07:18:44","guid":{"rendered":"https:\/\/smartairfilters.com\/mn\/?p=423"},"modified":"2019-08-14T06:02:46","modified_gmt":"2019-08-14T06:02:46","slug":"masks-really-work","status":"publish","type":"post","link":"https:\/\/smartairfilters.com\/mn\/en\/blog\/masks-really-work\/","title":{"rendered":"Do Pollution Masks Really Work?"},"content":{"rendered":"

When a billion people in China (and quite a few expats) woke up to the severe air pollution in\u00a0<\/span>almost every city in China<\/a>, it forced a billion people to become experts in a complicated scientific question: Do masks work?<\/p>\n

Since then, I\u2019ve given talks with hundreds of people all around China about how to protect themselves from air pollution. In those talks, I\u2019ve heard doubts from smart, skeptical people. Here I\u2019ll answer those doubts because, fortunately, smart, skeptical scientists (plus one dedicated nerd\u2014yours truly) have empirically tested these questions.\u00a0<\/span><\/p>\n

Update: if you\u2019re living in India, we\u2019ve done some\u00a0<\/span>India-specific tests with some of the most common masks available in India<\/a>\u00a0<\/span>\u2013 including kids\u2019 masks!<\/p>\n

 <\/p>\n

1. \u201cThere\u2019s no way they capture the really small particles.\u201d<\/strong><\/h3>\n

 <\/p>\n

The skeptic case:\u00a0<\/span>
\n<\/strong><\/h4>\n

The most dangerous particles are the smallest particles, but masks are so thin. How could they possibly get the smallest particles?<\/p>\n

 <\/p>\n

The scientific test:<\/strong><\/h4>\n

Researchers from the University of Edinburgh tested different common masks\u00a0<\/a>by running a diesel generator (to mimic car exhaust) and piping the exhaust through different masks. They used a particle counter to see how many particles made it through the mask.\u00a0Here\u2019s my super scientific rendering of the setup:<\/span><\/p>\n

 <\/p>\n

\"\"<\/p>\n

 <\/p>\n

One important detail:\u00a0<\/span>the particle counter they used<\/a>\u00a0<\/span>measures down to .007 microns. We\u2019re talking about truly tiny particles here!<\/p>\n

First they tried a simple cotton handkerchief. Sometimes I see bikers in China wearing these.<\/p>\n

 <\/p>\n

\"\"<\/p>\n

 <\/p>\n

Not great, 28% of particles blocked.<\/p>\n

Next they tried a cheap surgical mask.<\/p>\n

 <\/p>\n

\"\"<\/p>\n

 <\/p>\n

Surprisingly good! (Fit tests generally show lower results\u2013see below\u2013but still a lot higher than most people\u2019s intuition.)<\/p>\n

Next they tried several bike masks.<\/p>\n

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\"\"<\/p>\n

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Most were around 80%.<\/p>\n

Then they tried several cheap 3M masks.<\/p>\n

 <\/p>\n

\"\"<\/p>\n

 <\/p>\n

They all scored over 95%. Pretty good!<\/p>\n

Conclusion:<\/strong>\u00a0<\/span>Masks capture even very small particles.<\/p>\n

 <\/p>\n

2. \u201cOK, they capture the small particles, but when you wear them, all the air just leaks in the side.\u201d\u00a0<\/strong><\/h3>\n

 <\/p>\n

The skeptic case:\u00a0<\/span><\/strong><\/h4>\n

Masks work in theory, but those tests aren\u2019t on real faces! When you actually wear them, you can\u2019t get a good enough fit, so they\u2019re basically useless.<\/p>\n

<\/h4>\n

The scientific test:<\/strong><\/h4>\n

This question is tougher to answer because you have to measure the mask while you\u2019reactually wearing it. For that, you need a really expensive\u00a0<\/span>fit test machine<\/a>. Fortunately, I begged and begged 3M until they let me use their lab in Beijing:<\/p>\n

 <\/p>\n

\"\"<\/p>\n

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The blue tube is sampling air outside the mask, while the white tube is sampling air from inside the mask (more details on the methods\u00a0<\/span><\/a>here<\/a>\u00a0).\u00a0<\/span><\/p>\n

 <\/p>\n

Smart Air co-founder Anna Guo and Beijing-based Dr. Richard Saint Cyr\u00a0<\/span>also tested masks<\/a>, so I combined all of our data. Here\u2019s how well the masks worked on our faces:<\/p>\n

 <\/p>\n

\"\"<\/p>\n

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How well do masks work for the broader population?\u00a0<\/span><\/strong><\/h3>\n

It\u2019s important to make clear: masks that fit my face well might not fit other people\u2019s faces well. However, there is evidence from a broader population that masks fit most people well. A scientific study of 3M masks on 22 Chinese people\u00a0<\/span>found a median fit score of 99.5%<\/a>\u2013essentially the same as the top results from Dr. Saint Cyr and me.<\/p>\n

Best yet, effective masks don\u2019t cost a lot of money.<\/p>\n

 <\/p>\n

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 <\/p>\n

Exception: Gas Pollutants<\/strong><\/h4>\n

Masks are great, but note that these are tests on particulate pollution (such as PM2.5). Most commercially available masks don\u2019t target gas pollutants like NO2 and O3, so masks are not giving 100% protection.<\/p>\n

 <\/p>\n

3. Is there a documented health benefit of wearing a mask?<\/strong><\/h3>\n

This is probably the hardest question to answer. However, there are two solid studies that have randomly assigned people in Beijing to wear masks or not and measured their heart rate and blood pressure (1<\/a>\u00a0<\/span>,\u00a02<\/a>).\u00a0<\/span><\/p>\n

 <\/p>\n

\"\"<\/p>\n

 <\/p>\n

While wearing masks, people had lower blood pressure and better-regulated heart rates.<\/span><\/p>\n

 <\/p>\n

\"\"<\/p>\n

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Conclusion:\u00a0<\/span><\/strong>Masks capture even the smallest particles\u2014even while people are wearing them\u2014and they have documented health benefits. That should be enough to satisfy even the skeptics!<\/span><\/p>","protected":false},"excerpt":{"rendered":"

When a billion people in China (and quite a few expats) woke up to the severe air pollution in\u00a0almost every city in China, it forced a billion people to become experts in a complicated scientific question: Do masks work? Since then, I\u2019ve given talks with hundreds of people all around … Read more<\/a><\/p>\n","protected":false},"author":4580,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-423","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"_links":{"self":[{"href":"https:\/\/smartairfilters.com\/mn\/en\/wp-json\/wp\/v2\/posts\/423","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/smartairfilters.com\/mn\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/smartairfilters.com\/mn\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/smartairfilters.com\/mn\/en\/wp-json\/wp\/v2\/users\/4580"}],"replies":[{"embeddable":true,"href":"https:\/\/smartairfilters.com\/mn\/en\/wp-json\/wp\/v2\/comments?post=423"}],"version-history":[{"count":3,"href":"https:\/\/smartairfilters.com\/mn\/en\/wp-json\/wp\/v2\/posts\/423\/revisions"}],"predecessor-version":[{"id":737,"href":"https:\/\/smartairfilters.com\/mn\/en\/wp-json\/wp\/v2\/posts\/423\/revisions\/737"}],"wp:attachment":[{"href":"https:\/\/smartairfilters.com\/mn\/en\/wp-json\/wp\/v2\/media?parent=423"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/smartairfilters.com\/mn\/en\/wp-json\/wp\/v2\/categories?post=423"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/smartairfilters.com\/mn\/en\/wp-json\/wp\/v2\/tags?post=423"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}