{"id":4921,"date":"2017-11-09T11:54:55","date_gmt":"2017-11-09T03:54:55","guid":{"rendered":"https:\/\/smartairfilters.com\/?p=4921"},"modified":"2021-12-13T16:20:00","modified_gmt":"2021-12-13T08:20:00","slug":"purifiers-perform-worse-when-pollution-high","status":"publish","type":"post","link":"https:\/\/smartairfilters.com\/en\/blog\/purifiers-perform-worse-when-pollution-high\/","title":{"rendered":"ALL Purifiers Perform Worse When Air Pollution is Bad: (And How to Fix It)"},"content":{"rendered":"

Most air purifier companies hide the fact that outdoor air pollution drastically affects air purifier performance \u2013 even when used indoors. When outdoor air pollution is bad, purifiers achieve a smaller percentage reduction. It becomes harder to reach safe levels indoors. Here’s what you can do to ensure you are breathing safe clean air, even during a pollution apocalypse.<\/p>\n\n\n\n

Take an average day in Delhi or Beijing, for example. Not a bad day. Just a regular, average day. The air coming into our lungs on those average days is 8 to 12 times the World Health Organization\u2019s annual limit<\/a>.<\/p>\n\n\n\n

\"Average<\/figure><\/div>\n\n\n\n

That\u2019s bad! But a lot of people don\u2019t start to get worried until the air looks like this outside.<\/p>\n\n\n\n

\"Beijing<\/figure><\/div>\n\n\n\n

That\u2019s not just my anecdotal experience. I can see those spikes in interest when I analyze internet searches for \u201cpurifier\u201d against PM2.5 pollution levels:<\/p>\n\n\n\n

\"\"<\/figure><\/div>\n\n\n\n

And all of this makes sense. We\u2019re more scared when the air pollution outside is really bad. But there\u2019s a problem. Air purifiers\u2014and I mean all air purifiers\u2014perform worse at the exact times the most people are rushing to use them.<\/p>\n\n\n\n

Now that\u2019s a big claim. ALL purifiers? I\u2019m a scientist for a living<\/a>, so I\u2019m wary of words like \u201call\u201d and \u201calways.\u201d<\/p>\n\n\n\n

But since I got interested in building DIY purifiers to protect my lungs from Beijing\u2019s air, I\u2019ve tested lots of different types of purifiers. My favorite test is what I call a \u201croom test.\u201d It\u2019s exactly like how most people use purifiers\u2014in a regular bedroom, with naturally occurring pollution, and no special seal around the doors or windows.<\/p>\n\n\n\n

\"Air<\/figure><\/div>\n\n\n\n

In those tests, I calculate what percentage reduction the air purifier made in the amount of 0.5 micron particles in the room air. For example, on this day, the Original DIY purifier<\/a> reduced particulate by 85%.<\/p>\n\n\n\n

\"\"<\/figure><\/div>\n\n\n\n

But while I\u2019m doing these tests, the atmosphere is helping me run a little experiment. That\u2019s because some days the outdoor air is 20 micrograms, and some days it\u2019s 200 micrograms. And what I find with every machine I test is that percentage reductions are lower on days with bad air pollution. For example, here\u2019s the percentage reductions achieved by the Blue Air 203 (y-axis) on days with different outdoor PM2.5 levels (x-axis):<\/p>\n\n\n\n

\"BlueAir<\/figure><\/div>\n\n\n\n

On days with bad outdoor air pollution (on the right side of the graph), the Blue Air achieved lower percentage reductions. That\u2019s despite the fact that the Blue Air was running on its highest setting (same for all tests below). Full details on the test method here<\/a>.<\/p>\n\n\n\n

It\u2019s not just a Blue Air phenomenon. Here\u2019s my test data for the Philips:<\/p>\n\n\n\n

\"Phillips<\/figure><\/div>\n\n\n\n

The same pattern is there for the humble DIY 1.1\u2026<\/p>\n\n\n\n

\"\"<\/figure><\/div>\n\n\n\n

\u2026as well as the \u201ccleanest air guaranteed\u201d IQ Air:<\/p>\n\n\n\n

\"IQ<\/figure><\/div>\n\n\n\n

And the DIY Cannon:<\/p>\n\n\n\n

\"\"<\/figure><\/div>\n\n\n\n

Is There Any Way Around This Problem? <\/h3>\n\n\n\n

What\u2019s an air-breather to do? If you want to absolutely guarantee your indoor air will stay below the World Health Organization\u2019s 25 microgram limit<\/a>, there are two things you can do:<\/p>\n\n\n\n

1. Seal up the doors and windows<\/h4>\n\n\n\n

Sealing up the doors and windows will make it harder for that outdoor pollution to get in, and it will make your purifier more effective<\/a>.<\/p>\n\n\n\n

\"\"<\/figure><\/div>\n\n\n\n

But if your home has chemicals coming from recent remodeling or new furniture, you might not want such a good seal! And even with a good seal, that won\u2019t guarantee clean air.<\/p>\n\n\n\n

2. Bring in back up<\/h4>\n\n\n\n

The only real way I can see to truly guarantee clean air in the worst airpocalypse is to overpower it. We can do that by using a second purifier (like Dr. Saint Cyr did<\/a> in his Beijing apartment) or buying a machine that is rated for an even bigger room. For example, if you have a 15m2<\/sup> bedroom and 30m2<\/sup> living room, the Blast Mini<\/a> should easily be able to overpower that because it\u2019s rated for up to 85m2<\/sup>. And that strategy brings an added bonus: it’s quieter!<\/p>\n\n\n\n

\"Meet<\/figure><\/div>\n\n\n\n
\n\n\n\n

Open Data<\/strong><\/p>\n\n\n\n

As always, I\u2019m posting the original test data and more details on the methods for fellow data nerds (and if anyone wants to replicate the tests).<\/p>\n\n\n\n

Extra Data and Methods<\/h2>\n\n\n\n

All of the tests were done in a 15m2<\/sup> bedroom in Beijing, Chaoyangmen. I\u2019d rate the seal around the doors and windows as average for a Chinese apartment. I\u2019ve seen better, and I\u2019ve seen worse.<\/p>\n\n\n\n

The graphs in the main article use the average outdoor PM2.5 micrograms during the overnight tests, as measured by the US Embassy in Beijing. This does not account for the times when PM2.5 goes up or down during the night, so most of the outlier datapoints are probably because the average PM2.5 masks the change overnight. The y-axis is the percent reductions in particles 0.5 microns and above, calculated from the start of the test, at the beginning of the night before the purifier was turned on, versus the average of the last four hours of the test (before waking up). The particle counter was a Dylos Pro.<\/p>\n\n\n\n

More details on the test method are in my earlier comparison tests of the DIYs and the big brands<\/a>. There are also more details in my earlier here<\/a> and here<\/a>.<\/p>\n\n\n\n

Is the effect stronger for some machines? <\/strong><\/p>\n\n\n\n

If you look carefully at the graphs, you\u2019ll notice that some machines saw some really nasty air and some didn\u2019t. For example, the worst the DIY 1.1 saw was 322 micrograms. The worst the Philips saw was 108 micrograms.<\/p>\n\n\n\n

That makes me hesitant to compare how big of a drop there is across the machines. I\u2019d want a larger dataset before I\u2019d be confident to interpret the average drop in effectiveness between machines. However, it would make sense that machines that put out a higher volume of air should see smaller drops in effectiveness on bad days.<\/p>\n\n\n\n

Original Data<\/h3>\n\n\n\n

Cannon Data: <\/strong>The Cannon data comes from the original Cannon tests<\/a> and from tests of the Cannon + pre-filter, which we found made almost no difference in effectiveness. The Cannon + pre-filter test data is available in the post about the Xiaomi auto-mode<\/a>.<\/p>\n\n\n\n

Philips and Blue Air Data:<\/strong> This data is in my directly comparable purifier tests<\/a>.<\/p>\n\n\n\n

IQ Air Data: <\/strong>The IQ Air data comes from my other direct comparison tests<\/a>.<\/p>\n\n\n\n

DIY 1.1 Data: <\/strong>The data for the DIY 1.1 is in the DIY 1.1 test post<\/a>.<\/p>\n\n\n\n

\n\n\n\n

How I Protect Myself<\/strong><\/p>\n\n\n\n

Smart Air is a  certified B Corp committed to combating the myths big companies use to inflate the price of clean air.<\/p>\n\n\n\n

Smart Air provides empirically backed<\/a>, no-nonsense purifiers and masks, that remove the same particles as the big companies for a fraction of the cost. Only corporations benefit when clean air is a luxury.<\/p>\n\n\n\n

Check out the Sqair!<\/a><\/p>\n\n\n\n

\"\"<\/a><\/figure><\/div>","protected":false},"excerpt":{"rendered":"

Most air purifier companies hide the fact that outdoor air pollution drastically affects air purifier performance \u2013 even when used indoors. When outdoor air pollution is bad, purifiers achieve a smaller percentage reduction. It becomes harder to reach safe levels indoors. Here’s what you can do to ensure you are … <\/p>\n

Read more<\/a><\/p>\n","protected":false},"author":1035,"featured_media":4913,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"_relevanssi_hide_post":"","_relevanssi_hide_content":"","_relevanssi_pin_for_all":"","_relevanssi_pin_keywords":"","_relevanssi_unpin_keywords":"","_relevanssi_related_keywords":"","_relevanssi_related_include_ids":"","_relevanssi_related_exclude_ids":"","_relevanssi_related_no_append":"","_relevanssi_related_not_related":"","_relevanssi_related_posts":"","_relevanssi_noindex_reason":"","footnotes":""},"categories":[17,190],"tags":[283,221,222,311,310,550,544],"class_list":["post-4921","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-air-pollution","category-air-purifiers","tag-air-purifier","tag-blue-air","tag-iq-air","tag-phillips-ac4072","tag-phillips-review","tag-statistics","tag-tests","resize-featured-image"],"acf":[],"_links":{"self":[{"href":"https:\/\/smartairfilters.com\/en\/wp-json\/wp\/v2\/posts\/4921","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/smartairfilters.com\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/smartairfilters.com\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/smartairfilters.com\/en\/wp-json\/wp\/v2\/users\/1035"}],"replies":[{"embeddable":true,"href":"https:\/\/smartairfilters.com\/en\/wp-json\/wp\/v2\/comments?post=4921"}],"version-history":[{"count":25,"href":"https:\/\/smartairfilters.com\/en\/wp-json\/wp\/v2\/posts\/4921\/revisions"}],"predecessor-version":[{"id":20105,"href":"https:\/\/smartairfilters.com\/en\/wp-json\/wp\/v2\/posts\/4921\/revisions\/20105"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/smartairfilters.com\/en\/wp-json\/wp\/v2\/media\/4913"}],"wp:attachment":[{"href":"https:\/\/smartairfilters.com\/en\/wp-json\/wp\/v2\/media?parent=4921"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/smartairfilters.com\/en\/wp-json\/wp\/v2\/categories?post=4921"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/smartairfilters.com\/en\/wp-json\/wp\/v2\/tags?post=4921"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}