Thursday, March 27, 2014

Citizen Science: The ideal air quality sensor

I am looking for a particulate sensor that we can use with the Eastern Coachella valley Environmental Justice community. The community member hosting the device will benefit from the technology by understanding their air quality, their health and how it compares to the rest of the world. Its an exercise in public health education and empowerment. When a family hosts a device, it could potentially inform and educate them about the air quality parameters that are used; how their community ranks with the rest of the country and localize some of the air quality warnings.

The ideal outdoor air quality sensor should have the following abilities:
CRITERIA:
  1. Be robust, small, portable and weather resistant for an outdoor site.
  2. Be unobtrusive in its appearance to detract from vandalism
  3. Have AC and DC power options where it could be run from a battery and/or plugged in
  4. Require none or very simple zeroing and calibrations that can be run by a citizen with a high school education. 
  5. Be net-workable and Geolocated to allow real time comparison on a distributed network
  6. Real-time parameters with no need to send the samples to the lab.
  7. Be less than $100

The PARAMETERS that it should measure are listed on the SCAQMD map site and include:
  • Ground-level Ozone (O3)
  • Particle Pollution, also known as particulate matter (PM10 and PM2.5)
  • Carbon Monoxide (CO)
  • Sulfur Dioxide (SO2) and
  • Nitrogen Dioxide (NO2).

Additional parameters relevant for the Eastern Coachella Valley include: 
  • VOCs, combustible gas and Methane: for the frequent odor issues in the area
  • Temperature and Relative Humidity:   to calibrate the other  sensors against
Work already done? 
The reason I am writing this is to see if the work has already been done. I know that a few groups are working on this. Many public buses in San Francisco collect this data, but there are limited sensors available for sale to the public. here are some options that I have seen which approximate most of my requested parameters and criteria. 

DIY projects: 

A community lead sensing network with the sensors, base station and network. It starts with CO and NO2 parameters and you can add on additional sensors such as the particulate counter. There is a pretty good forum on the website with links to many others. You can buy a ready made one from wicked device, then add those particulate or other sensors as plug-and-play.

A DIYer Chris: a website on how to put a particulate sensor together
I thought of starting with the diagrams that this website shows and moving on from there.We are going to order a Dylos air sensor and we already have a hazdust epam5000. 

The most detailed instructions I could find. 

This one has a nice set of DIY instructions but doesn't include the SHARP dust sensor. 

Marketed Solutions:
The Dylos Air sensor: Measure dust for around $300

the Lascar CO sensor: Measure CO and log data for about $150




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