Dylos Air Particule counter experimentation, part 1.

Posted on September 8th 2013
Share: aqicn.org/faq/2013-09-08/dylos-air-particule-counter-experimentation-part-1

The most common way to measure air quality, as far as it concerns PM10 and PM2.5 particules, is to use the so-called Beta Attenuation Monitors, aka BAM (see picture on the right). Those are profesional equipment, and also the only official equipment used for Air Quality monitoring in China, US, and most of the world. The most famous manufacter is the US-based company called Met-One.

The BAM working principle is quite simple: It measures the decrease in the number of beta particles (electrons) transmitted through a thin layer of particulate matter (PM). As the thickness of the PM layer is increased, the lower the number of beta particules can go through.



The only problem with this kind of BAM equipment is that the cost, estimated to 120K CNY (15K EUR). In China only, there are around 500 of those (arround 10 station for each city), and yet, this is not enough as there are still many cities without any PM2.5 readings. In Thailand, there are 21 automatic (i.e. with hourly reading) stations, but none of them provide PM2.5 data. And in Vietnam, there are only 3 stations for the entire country.


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So, while waiting for all the world governments to invest in brand new Beta Attenuation Monitors, is there anything that could be done? Then answer is yes! There are actually relatively affordable equipment that can be used to measure the PM10 and PM2.5 based Air Quality. The most famous one is the Dylos Air Particule counter:




If you want to know how the Dylos Air Particule counter is working, please refer to the excellent reverse engineering work from Matthias from woodgears.ca, or simply from Dylos's website (www.dylosproducts.com/). You can also refer to the resarch paper A low-cost instrument for environmental particulate analysis based on optical scattering to understand the theory behind the measurement.

Note: this article was written in 2013. While the Dylos monitor is still a good product, there is nowdays much better and affordable monitoring products, so we do not recommend purchasing the Dylos product anymore.
You can for instance check the GAIA air quality monitoring stations product range from ES Labs.

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In order to prove the point that such Dylos equipment could be used as an temporary solution for measuring Air Quality, we setup a small experiment in our labs, based on the Dylos DC 1100 Pro, with PC interface. The Dylos PC 1000 pro is relatively inexpensive, and can be bought from Amazon for $319.

Please, note that you must get the pro, with PC interface version. The Pro is needed to be able to measure particules as small as PM2.5, as the non-pro version can only detect PM10 particules or larger. The PC interface version mandatory as it provides a Serial interface, needed for automatically extracting the data from the dylos monitor to the PC.

If you buy the equipment from China, from taobao or jndong (jd.com), please be carefull and make sure to order the right version. The most common version in the DC 1100 without PC interface. Only few shop on taobao provide this right version, and at the present time of writing, jd.com does not even provide the correct version. If you need help for buying for equipement from China, you can contact us with the subject "Dylos Equipment Order", and we will help you for the ordering.


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In order to automatically extract the data to send it to the server, a Raspberry PI ($56) and a serial to USB cable ($9) is used, totalizing a BOM of $375. (You can buy all this material from Amazon by clicking on the images below)

Dylos DC1100 pro
with PC interface
Serial to USB cable Raspberry PI


The documentation and scripts for connecting the Dylos particules counter to the Raspberry PI, and automatically uploading the dylos data to the World Air Quality Index project server are available freely from github: github.com. If you have any questions, you can contact us with the subject "Dylos Experiment".

Also, please note that when you setup your Dylos Particule Counter outside, you need to be carefull where you locate it. Ideally, it should be in a place which is not too windy, as the wind can have a significant impact on the readings (The reason is that the Dylos counter is using a simple fan to get the air inflow, and the volume of air inflow per minute needs to be constant in order to have accurate readings ~ This simple fan is one of the reason why this kind of material is so affordable compared to the professional MetOne BAM sensors).


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In order to compare the Dylos reading with the BAM reading, we use the BAM data provided by Beijing Chaoyang Agricultural Exhibition Hall (朝阳农展馆), as our station is located in the Sanlitun Soho area.

And here is the real-time result: The line in blue is the dylos reading (updated every minute), and the line in red the BAM data (updated every hour). The first graph is to compare the PM10 reading, while the second graph compares the PM2.5. Also, please note that the BAM data is provided in µg directly, i.e. not converted to the AQI grades.



(Click on the picture to open the real time version)



As you can see, the similitude between dylos and BAM reading is quite high, but yet not always fully comparable. In the second part of this post (which we will write after two month, once we have collected enough data), we will provide more statistical data about the readings.

Also, if you are interested in joining this experiment, by setting up your own Dylos station, please contact us. We will provide all the scripts and detailled setup, as well as to add you the sensor database, so that you can see your readings in real-time.


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As a follow up of this post, you can check the new post about the Dylos Air Particule Conter experiment maintenance.

oOo


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    空気の質と大気汚染指数で

    大気品質レベルについて

    指数大気質指数の分類(米国)健康影響 / カテゴリ粒子状物質(PM10,PM2.5)
    0 - 50良い - Good通常の活動が可能なし
    51 -100並 - Moderate特に敏感な者は、長時間又は激しい屋外活動の減少を検討非常に敏感な人は、長時間または激しい活動を減らすよう検討する必要がある。
    101-150敏感なグループにとっては健康に良くない - Unhealthy for Sensitive Groups心臓・肺疾患患者、高齢者及び子供は、長時間又は激しい屋外活動を減少心疾患や肺疾患を持つ人、高齢者、子供は、長時間または激しい活動を減らす必要がある。
    151-200健康に良くない - Unhealthy上記の者は、長時間又は激しい屋外活動を中止
    すべての者は、長時間又は激しい屋外活動を減少
    心疾患や肺疾患を持つ人、高齢者、子供は、長時間または激しい活動を中止する必要がある。それ以外の人でも、長時間または激しい活動を減らす必要がある。
    201-300極めて健康に良くない - Very Unhealthy上記の者は、すべての屋外活動を中止
    すべての者は、長時間又は激しい屋外活動を中止
    心疾患や肺疾患を持つ人、高齢者、子供は、全ての屋外活動を中止する必要がある。それ以外の人でも、長時間または激しい活動を中止する必要がある。
    300+危険 - Hazardous上記の者は、屋内に留まり、体力消耗を避ける
    すべての者は、屋外活動を中止
    全ての人が屋外活動を中止する必要がある。特に、心疾患や肺疾患を持つ人、高齢者、子供は、屋内に留まって激しい活動を避け静かに過ごす必要がある。
    (Reference: see wikipedia,and cn.emb-japan.go.jp/)

    あなたは空気の質や汚染についての詳細をお知りになりたい場合は、WikipediaAirNowを参照してください。

    北京の医者Richard Saint Cyrの非常に便利な健康アドバイスについては、 www.myhealthbeijing.com をチェックしてください。


    Usage Notice: All the Air Quality data are unvalidated at the time of publication, and due to quality assurance these data may be amended, without notice, at any time. The World Air Quality Index project has exercised all reasonable skill and care in compiling the contents of this information and under no circumstances will the World Air Quality Index project team or its agents be liable in contract, tort or otherwise for any loss, injury or damage arising directly or indirectly from the supply of this data.



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    言語を選択:


    Temperature unit:
    Celcius