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Hydrogen Sulfide Sensing

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Hydrogen sulfide, which is a well documented but little understood health hazard, is one of the leading causes of injury in the workplace. Health issues have been clearly linked to H2S, and since 2011 the EPA has required the oil and gas to report their emissions to the Toxics Release Inventory (TRI). Despite this much hydrogen sulfide still gets into the air with little regulation (Fracking Boom Spews Toxic Air Emissions on Texas Residents). Public Lab researchers are attempting to innovate novel, low-cost community based approaches to environmental health problems like hydrogen sulfide, so that communities and workers may begin not only developing systems to track their exposure, but also generating data and evidence in order to scientifically validate their experiences.

The photopaper sensing tool is being developed to detect hydrogen sulfide in an affordable, quantifiable manner. In September of 2011, Public Laboratory members met with residents of Garfield County, Colorado to discuss the growing hydrogen sulfide problem in their small, rural community. The community had recently organized to take a gaseous grab sample from one resident’s kitchen sink. Analysis of the grab sample showed hydrogen sulfide levels of more than 185 times above the long-term exposure level recommended by the EPA (Gassed by Global Community Monitoring). The family, in which the son developed painful skin lesions and other symptoms coincident with this exposure, was forced to abandon the house. They are seeking legal assistance, but so far, neighboring gas development companies have denied association with the families water contamination. The grab sample, while able to capture one record of exposure, was costly (over $500) and had to be shipped to a lab in California within 24 hours in order to ensure the samples viability. The family did not hear results of the test for weeks, all the while continuing their exposure.

Basic Information on Hydrogen Sulfide

Hydrogen Sulfide Monitoring in Gas Patch: Background

Hydrogen Sulfide: Information on the Gas

Conversion from µg/m3 to ppm hydrogen sulfide

Development History

We currently have two approaches to sensing hydrogen sulfide in development.

First Prototype: Digital Sensor

Our first prototype used a digital sensor for hydrogen sulfide. Advantages of this system is that data from the sensor could be logged over time and that tool is reusable and portable. However the Figaro TGS 825 sensor itself is relatively expensive--approximately $60 for an individual sensor and $40 in bulk.


Arduino and Industrial H2S Sensor

More information on the digital sensor:

Prototype H2S Sensor

Temperature and Humidity Sensors to Correct H2S

Arduino + Figaro Hydrogen Sulfide Sensor

Arduino Patch for Detecting Hydrogen Sulfide

Hydrogen Sulfide Detection for Fart Detector

Second Prototype: Photographic Paper

Our second prototype uses photographic paper to detect hydrogen sulfide. The silver halide in photographic paper tarnishes when exposed to H2S. The paper changes color inside the canisters depending on the level of H2S it has been exposed to, with darker strips indicating higher levels of exposure. This method is low-cost, easy to assemble using everyday materials, and may be more accessible to non-programmers.

Film-based Hydrogen Sulfide test

Photographic Paper for H2S Sensing

More information on the photographic paper:

Hydrogen Sulfide Testing with Black and White Film

Hydrogen Sulfide Dosimeter

Hydrogen Sulfide Tarnishing Silver

Controlled Testing with B&W Film Hydrogen Sulfide Detectors


This project is based on these two papers by geologist C. J. Horwell and colleagues that used photographic paper to measure hydrogen sulfide concentrations near volcanos in New Zealand.

Horwell, C.J., Allen, A.G., Mather, T.A., Patterson, J.E., 2004. Evaluation of a simple passive sampling technique for monitoring volcanogenic hydrogen sulphide. J. Environ. Monitor. 6, 630 - 635. Horwell_JEM_2004_copy.pdf

Horwell, C.J., Patterson, J.E., Gamble, J.A., Allen, A.G., 2005. Monitoring and mapping of hydrogen sulphide emissions across an active geothermal field: Rotorua, New Zealand. J. Volcanol. Geotherm. Res. 139, 259-269. Horwell_JVGR_2005_copy.pdf


Original photopaper map made by Horwell et al.

Field Test Sites

Aztec, New Mexico


Map of area to be tested in Aztec, NM

Choosing Test Sites in Aztec, NM

Identifying Wells in Field and Experiment Design

Collection and Processing of Aztec Test Strips

Analyzed Results and Suggested New Steps for H2S Testing in Aztec, New Mexico

New Experimental Design, Aztec, New Mexico

New Container Tests, Aztec, New Mexico

Designs for Next Round of Experiments, Aztec, New Mexico

Next Round of Experiments

Putting Together H2S Test Kit

Easy Way to Make Precise Maps

Fist Experiment Analyzed

Powder River Basin, Wyoming


Results of three rounds of testing in Deaver, WY

Hydrogen Sulfide Photopaper Sensing Tool - Development Notes, Deaver

Photopaper Sensing Tool - Development Notes, Deaver, WY

NU Darkroom Setup

H2S Photopaper Test Assembly

Strip Processing Notes

Wyoming Hydrogen Sulfide Testing 2013-2014

How to make your own


Canisters in the process of being set up

Framing the Problem

How to Guide:

Download a copy: H2SphotopaperHowTo_ew_.doc

Short-term goals:

  1. to successfully sense hydrogen sulfide with photographic paper SmallBlackCheckmark.jpg
  2. to develop step by step guides to making the tools SmallBlackCheckmark.jpg
  3. to standardize the photopaper test within laboratory conditions in Louisiana
  4. to develop open source tools for analyzing the photopaper
  5. to design a public lab kit

Start Contributing and Get involved!

If you are interested in helping develop hydrogen sulfide sensing, please contribute thoughts, comments and research notes on this page as well as join us on the Public Lab mailing list.

Currently active work on the film assay is being done at Northeastern University by Sara Wylie, Elisabeth Wilder, Deb Thomas, Cait Kennedy, Megan McLaughlin, and Hannah Gartner.

Feel free to contact any of the people listed above if you are interested in getting more involved. You can also try following the prototype documentation to make your own film testing strips, and be sure to share any new tests sites or uses for this tool.

This project is partially funded by a grant from the American Anthropology Association, Anthropology and Environment section

See recent code activity on GitHub Pulse.

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