Loads of tests<\/a>\u00a0have found this in labs and in real-world homes. I\u2019ve tested the hell out of this,\u00a0in my room<\/a>,\u00a0in bigger rooms<\/a>,\u00a0for 200 days of Beijing air<\/a>,\u00a0comparison tests against the most expensive machines available<\/a>,\u00a0with no one at home<\/a>\u2026 purifiers reduce particulate pollution (and gas pollutants<\/a>) in the home.<\/p>\n <\/p>\n 2. We know that PM2.5 kills people<\/strong><\/p>\n Researchers estimate<\/a>\u00a0<\/span>that air pollution causes one in six deaths\u2014and one in four in places as polluted as India.<\/p>\n <\/p>\n 3. We don\u2019t know whether purifiers make people healthier\u2014until now<\/strong><\/p>\n So you\u2019d think that means we know air purifiers make people healthier, but research is surprisingly hard to find. Fortunately, researchers have just started to publish good studies testing this question.<\/p>\n <\/p>\n Researchers\u00a0gave 35 college students in Shanghai real or fake purifiers<\/a>\u00a0and tracked several health markers for two days. Researchers tested the students\u2019 lung function and several health markers in their blood.<\/p>\n First, reality check: did the purifiers reduce the number of particles in the air? The red line here is outdoor PM2.5. The blue line is indoor PM2.5 for students using the fake purifier.<\/p>\n <\/p>\n <\/p>\n Not surprisingly, fake purifiers don\u2019t work. And note that these are\u00a0bad\u00a0levels of pollution.\u00a0The World Health Organization\u2019s\u00a0<\/span>annual limit is 10 micrograms<\/a>. Without purifiers, these rooms were averaging 100 micrograms!<\/p>\n But check out PM2.5 levels in rooms with real purifiers (yellow).<\/p>\n <\/p>\n <\/p>\n PM2.5 levels were about half as high in rooms real purifiers.<\/p>\n But we already know purifiers reduce pollution. Did the purifier actually have effects on their bodies? Here\u2019s what having a real purifier did to measures of blood inflammation:<\/p>\n <\/p>\n <\/p>\n The students had significantly lower inflammation in their blood vessels. They also had lower blood coagulation (a marker of blood clotting):<\/p>\n <\/p>\n <\/p>\n And they had less constricted blood veins:<\/p>\n <\/p>\n One of the only things that did not improve significantly was their lung function:<\/p>\n <\/p>\n 1. The real harm of pollution isn\u2019t in our lungs<\/span><\/strong><\/p>\n My intuition with air pollution has always been that the biggest worry is lung problems like asthma and lung cancer. Air pollution does affect our lungs, but epidemiological studies are finding that effects on our lungs are far smaller than effects on our hearts and blood vessels. Air pollution\u00a0<\/span>kills about three times as many people<\/span><\/a>\u00a0through heart attacks and strokes than it does through lung cancer and other lung problems.\u00a0<\/span><\/p>\n <\/p>\n <\/p>\n 2. Health effects are real even for young, healthy college students<\/strong><\/p>\n Remember that these aren\u2019t old people. And they\u2019re not people who joined the study because they already had problems. They\u2019re young, healthy people. These results suggest that air pollution is taking a toll on our bodies, even if we are still mostly healthy.<\/p>\n <\/p>\n 3. The benefits were detectable within 48 hours<\/strong><\/p>\n These students\u2019 biomarkers of inflammation changed in just two days. Air pollution has long-term effects like cancer, but it also has short-term effects like blood inflammation and vein constriction (which probably help cause those long-term problems).<\/p>\n <\/p>\n But this is only one study\u2026<\/strong><\/p>\n Because these results are compared to people who received a fake purifier, they cannot be explained by a placebo effect. And like any finding, we should be wary of making conclusions based on a single study, but there are at least four other recent studies out with similar findings (1<\/a>,\u00a02<\/a>,\u00a03<\/a>,\u00a04<\/a>).<\/p>\n <\/p>\n Bottom line:<\/strong>\u00a0Air purifiers improve health markers in people living in polluted places, and these are not placebo effects.<\/p>","protected":false},"excerpt":{"rendered":" I’ve seen people ask if air purifiers depend on the placebo effect or do they actually work. I think this is a good question because we should not confuse the outcomes of (1) objectively reducing pollutants in the air versus (2) health effects. There are two things we know … <\/p>\n![\"\"](\"\/wordpress\/wp-content\/uploads\/2017\/12\/DIY-1.1-Sample-Test-Day-EN-1.png\")
<\/p>\nDo purifiers have real, non-placebo health effects?<\/h4>\n
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<\/p>\nThree Things I Didn\u2019t Know Before This Study<\/strong><\/h3>\n
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