Public Lab Research note

Field Testing the Shenyei PM sensor

by willie | April 01, 2014 15:38 01 Apr 15:38 | #10247 | #10247

Shenyei PPD42NS Gets an Accuracy Test

The Shenyei PPD42NS is a $15USD optical sensor that uses an LED and a lens to determine the concentration of dust in a partially closed chamber that draws in air from its surroundings. A group of academics interested in the applications of low-cost sensors for valid scientific air quality monitoring wanted to know how does this low-cost newly off-the-shelf PM monitor compare with costlier models used by governments (BAM-1020, Met One Instruments) researchers (GRIMM OPC, Model 1.108), and companies (DC1700, Dylos Corp).

This is what they found:

”Performance at 1 [hour] integration times was comparable to commercially available optical instruments costing considerably more.” Or to put it more plainly, the results of the low-cost sensor were about equivalent to more expensive ones when analyzing data at hourly intervals."

A full description of their methodology can be found here: Field_Calibrations_of_a_low-cost_aerosol_sensor_at_a_regulatory_monitoring_site_in_California-2014.pdf

Questions and next steps

In situations where a lower number of high-cost sensors are used to model exposure over large areas (as is often the case in cities where environmental monitoring infrastructure is scarce), how will new monitoring data generated from low-cost and accessible instrumentation be incorporated into regulatory decision making. This study suggests that the gap in data quality is shrinking and that deploying low-cost sensors as a complement to high-cost monitors has real potential. But that decision making part, that is still an important open question.

Why I'm interested

I work with the Earth Journalism Network, global community of environmental journalists interested in exploring how citizen science can improve the quality of our reporting.


thanks! watching this closely, i've purchased a few of these already.


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Cool Scott. I just bought 20 for the first batch of DustDuino being put together by Matt. We'll be testing these out over the summer so there is certainly more to come.

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Thanks for finding this, Willie! really cool.

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Awesome. I'm thinking about whether this could be used for silica monitoring... looks like this can detect PM2.5 and PM10, and those are in the range of "respirable" particulates cited as dangerous in areas with silica dust issues:

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Silica monitoring is definitely a use case especially where a point source (concrete aggregate plant?) is already identified. I also think that a coal train monitor, where the data logger is triggered by on board noise sensor would be a neat application.

I worked up a blog post after contacting one of the contributing scientists. It includes some of the limitations and unknowns associated with the shenyei:

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Copying in a comment I just left on the DustDuino post:

_So I think the sensor the Speck is using, the "Syhitech DSM501A" ( is ~$2, and the CMU folks said it compares well with the Shenyei ($15.90). I'm wondering about a radically cheap sensor that's just a Digispark ($12) plugged into the Syhitech sensor; it could cost < $20 total and just plug directly into your laptop. Or, could show an RGB LED with a color mapping for concentration. _

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Hi Willie! The next OpenHour ( is on Air Quality and Air Quality monitoring tools. Would love to hear about this there if you can make it.

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@mathew and I spent a week and got some Open Pipe Kit drivers written, including for the Shinyei. Take a look:

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