![\"dylos-pro-vs-us-embassy-en\"](\"http:\/\/smartairfilters.com\/wordpress\/wp-content\/uploads\/2017\/01\/Dylos-Pro-vs-US-Embassy-EN-300x225.jpeg\")
\nI did that test with the Pro model, but there\u2019s also a standard model that\u2019s $70 cheaper. At Smart Air, we call it the Standard Dylos.\n\nHow does this cheaper machine compare to the government measurements? If it’s similarly accurate, great! That means people can save money and get roughly similar results.\n\n![\"\"](\"\/wordpress\/wp-content\/uploads\/2017\/01\/Dylos-Pro-vs-Standard-1-Micron-EN.png\")
\nPro vs. Standard<\/h2>\nThe Dylos Pro and Standard are almost the same judging from their front looks. So what\u2019s the real difference?\n\nThe key is the size of particles they measure. Both of them have 2 size ranges. For the small particle channel, the Dylos Pro measures particles .5 microns and above, while the Standard Dylos measures 1 micron and above. On the large particle channel, the Pro measures 2.5 microns and above, while the Standard measures 5 microns and above. That means the Pro measures an extra range from .5 to 1 micron.\n\n![\"\"](\"\/wordpress\/wp-content\/uploads\/2017\/01\/1-Micron-Dylos-Measurement-Range-EN.png\")
\n\nThe machine governments use is called the Met One BAM<\/a>. It measures particles 2.5 microns and below (here’s how government PM2.5 sensors work<\/a>). If we put the measurement ranges of the BAM, the Dylos Pro, and the Standard Dylos together, here\u2019s what it looks like:\n\n![\"dylos-pro-vs-embassy-vs-dylos-en\"](\"http:\/\/smartairfilters.com\/wordpress\/wp-content\/uploads\/2017\/01\/Dylos-Pro-vs-Embassy-vs-Dylos-EN-300x200.png\")
\n\nThe Pro overlaps a bit more the government machine than the Standard. For that reason, I\u2019d expect the Pro correlates better with the government machine. But just how well do they compare empirically?\nThe Dylos Test<\/h2>\nLuckily I\u2019m not the only nerd interested in air pollution problem. An American living in Guangzhou bought the Standard and teamed up with me to test it against the US Consulate.\n\nFrom November 12th <\/sup>to 17th<\/sup>, she collected data with her Dylos Standard 70 times outside her apartment,which is close to Sun Yat-Sen University in Guangzhou. She also recorded the numbers of PM2.5 concentration released by the US Consulate.\n\n![\"dylos-1-micron-test-map\"](\"http:\/\/smartairfilters.com\/wordpress\/wp-content\/uploads\/2017\/01\/Dylos-1-Micron-Test-Map-1-300x296.jpeg\")
\nResults<\/h2>\nRemember how well the Pro correlated with the US Embassy? Here\u2019s what I found before (r <\/em>=.89<\/a>).\n\n\n\nLater I did another test by putting my DC1100 about 100 meters away from the US Embassy (much closer than my apartment). This time it turned out that the two numbers correlated at r <\/em>= .9 \u2013 slightly higher than in the first test.\n\n![\"dylos-pro-vs-us-embassy-closer-en\"](\"http:\/\/smartairfilters.com\/wordpress\/wp-content\/uploads\/2017\/01\/Dylos-Pro-vs-US-Embassy-Closer-EN-300x222.jpeg\")
\n\nHow does the Standard Dylos compare? Here\u2019s what we found:\n\n![\"standard-1-micron-dylos-vs-us-embassy-en\"](\"http:\/\/smartairfilters.com\/wordpress\/wp-content\/uploads\/2017\/01\/Standard-1-Micron-Dylos-vs-US-Embassy-EN-300x201.jpeg\")
\n\nThey correlate at r <\/em>= .85! Although that\u2019s a bit lower than the correlation between Dylos Pro and US Embassy, the two numbers are still strongly related. I think that result would surprise most people.\nConverting the Dylos 1 Micron Readings to PM2.5<\/h2>\nUsing this data, we can get a rough formula to convert between the Dylos 1 micron and the official numbers. For example, the 24-hour WHO limit is 25 \u00b5g\/m\u00b3, which is approximately 1,250 on the Standard Dylos.\n\n![\"1-micron-dylos-to-us-embassy-en\"](\"http:\/\/smartairfilters.com\/wordpress\/wp-content\/uploads\/2017\/01\/1-Micron-Dylos-to-US-Embassy-EN-300x195.png\")
\n\nThe simplest formula to convert the Dylos 1 micron to PM2.5 micrograms is:\n
Dylos 1 micron count \u00d7 0.02 = PM2.5 \u00b5g\/m3<\/strong><\/p>\nIf we use that formula to convert the Dylos numbers to micrograms, here\u2019s how well the numbers compare:\n\n![\"\"](\"\/wordpress\/wp-content\/uploads\/2017\/01\/Guangzhou-Test-Dylos-1-Micron-Graph-EN.png\")
\n\nOn average, the formula was off from the government numbers by 9.04 micrograms. That’s roughly as much as the average deviation of the Dylos Pro in our separate particle counter tests<\/a>.\nConclusion<\/h2>\nThe Standard correlates highly with the government numbers\u2014only slightly less well than the Pro model.\nLimitations<\/h2>\nThe conclusion is based on only one test in Guangzhou. We could draw stronger conclusions if we had more tests done in different locations and in different seasons.\nOpen Data<\/h2>\nAs always, I’m making the data and more testing details publicly available<\/a> for fellow nerds, as well as a new test<\/a> addressing some other factors like humidity.\n\nP.S. Thanks to Yiwen Wang for help translating and creating figures.","protected":false},"excerpt":{"rendered":"Lots of people are buying air quality monitors these days, but how do they compare to the official pollution numbers–are they accurate? When I bought a Dylos DC1100 Pro laser particle counter, \u00a0I did a comparison test with the US Embassy. I put my Dylos Pro outside the window of … <\/p>\n
\nResults<\/h2>\nRemember how well the Pro correlated with the US Embassy? Here\u2019s what I found before (r <\/em>=.89<\/a>).\n\n\n\nLater I did another test by putting my DC1100 about 100 meters away from the US Embassy (much closer than my apartment). This time it turned out that the two numbers correlated at r <\/em>= .9 \u2013 slightly higher than in the first test.\n\n\n\nHow does the Standard Dylos compare? Here\u2019s what we found:\n\n\n\nThey correlate at r <\/em>= .85! Although that\u2019s a bit lower than the correlation between Dylos Pro and US Embassy, the two numbers are still strongly related. I think that result would surprise most people.\nConverting the Dylos 1 Micron Readings to PM2.5<\/h2>\nUsing this data, we can get a rough formula to convert between the Dylos 1 micron and the official numbers. For example, the 24-hour WHO limit is 25 \u00b5g\/m\u00b3, which is approximately 1,250 on the Standard Dylos.\n\n\n\nThe simplest formula to convert the Dylos 1 micron to PM2.5 micrograms is:\n
Dylos 1 micron count \u00d7 0.02 = PM2.5 \u00b5g\/m3<\/strong><\/p>\nIf we use that formula to convert the Dylos numbers to micrograms, here\u2019s how well the numbers compare:\n\n\n\nOn average, the formula was off from the government numbers by 9.04 micrograms. That’s roughly as much as the average deviation of the Dylos Pro in our separate particle counter tests<\/a>.\nConclusion<\/h2>\nThe Standard correlates highly with the government numbers\u2014only slightly less well than the Pro model.\nLimitations<\/h2>\nThe conclusion is based on only one test in Guangzhou. We could draw stronger conclusions if we had more tests done in different locations and in different seasons.\nOpen Data<\/h2>\nAs always, I’m making the data and more testing details publicly available<\/a> for fellow nerds, as well as a new test<\/a> addressing some other factors like humidity.\n\nP.S. Thanks to Yiwen Wang for help translating and creating figures.","protected":false},"excerpt":{"rendered":"Lots of people are buying air quality monitors these days, but how do they compare to the official pollution numbers–are they accurate? When I bought a Dylos DC1100 Pro laser particle counter, \u00a0I did a comparison test with the US Embassy. I put my Dylos Pro outside the window of … <\/p>\n
\n\nThe simplest formula to convert the Dylos 1 micron to PM2.5 micrograms is:\n\n\nOn average, the formula was off from the government numbers by 9.04 micrograms. That’s roughly as much as the average deviation of the Dylos Pro in our separate particle counter tests<\/a>.\n