_This is the organizing page for research related to hydrogen sulfide in Public Lab._
(above: [DIY colorimetric strips](/notes/megan/9-7-2012/first-experiment-analyzed) reacting to H2S by @megan)
### What is hydrogen sulfide, what are its effects, and where is it found?
Hydrogen sulfide, with the chemical formula H2S, is a flammable gas that has a pungent odor at low concentrations and is odorless at higher concentrations. It can be a respiratory irritant and a neurotoxin. [Read more about hydrogen sulfide health effects](/wiki/hydrogen-sulfide-effects).
Hydrogen sulfide is naturally formed in low-oxygen conditions with sulfate present, such as in organic-rich sediments and thus in petrochemical source rocks. Upon exposure to oxygen, hydrogen sulfide readily oxidizes to sulfur dioxide or sulfate, and generally reacts within hours to days. [Read more about hydrogen sulfide sources and spatial and temporal variation](/wiki/hydrogen-sulfide-environment)
### How are hydrogen sulfide emissions and exposures regulated?
In the United States, hydrogen sulfide emissions are only federally regulated to the extent that they contribute to sulfur dioxide formation, and thus acid rain. These emissions are regulated through the Prevention of Significant Deterioration of major stationary sources review and permitting. Exposure to hydrogen sulfide is mostly regulated in terms of occupational exposure, with very few states regulating ambient exposure to this toxin. [Read more about hydrogen sulfide regulations](/wiki/hydrogen-sulfide-regulations)
## How can hydrogen sulfide be measured?
While there is no federal regulatory method for hydrogen sulfide in the US, labs, agencies, and oilfield workers often measure hydrogen sulfide gas through several different means:
* badges or glass tubes that change color
* continuously sampling electronic sensors, some worn by oilfield workers
* [air grab sampling](/wiki/air-sampling), as by the Bucket Brigades, tested with gas chromatography
> We're compiling information about the **pros, cons, prices, and sensitivity/limitations** of these techniques: [What are different commercially available hydrogen sulfide detection methods?](/notes/warren/12-04-2017/what-are-different-commercially-available-hydrogen-sulfide-detection-methods)
## Do-It-Yourself approaches to detection
There are three prototype, low-cost hydrogen sulfide detection methods currently being explored by Public Lab community members. These include:
* a [method using photographic paper](/wiki/hydrogen-sulfide-photopaper)
* a [copper tarnishing method](/wiki/hydrogen-sulfide-copper-pipe)
* a technique using a [Do-It-Yourself potentiostat](/notes/JSummers/03-10-2014/quantifying-airborne-hydrogen-sulfide)
* commercial [electronic H2S sensors](/wiki/hydrogen-sulfide-sensor) connected to a computer or #arduino
> Help out! Please help link the above bullet points to corresponding pages across this site.
We can't make progress on these techniques and resources without addressing our unknowns. Please ask questions to help shape the direction of our work!
## Related pages
See [other related wiki pages here](https://publiclab.org/wiki/tag/hydrogen-sulfide)
These activities are to guide you to test out hydrogen sulfide detection methods or use these tools in the field:
## Where can I find more information?
Two particularly good resources are listed below. Other hydrogen sulfide wiki pages (mentioned above) include additional relevant resources.
1. Agency for Toxic Substance and Disease Registry. 2016. Hydrogen Sulfide Fact Sheet. [https://www.atsdr.cdc.gov/ToxProfiles/tp114-c1-b.pdf](https://www.atsdr.cdc.gov/ToxProfiles/tp114-c1-b.pdf).
2. National Research Council. 2010. Acute Exposure Guidelines. [https://www.epa.gov/sites/production/files/2014-11/documents/hydrogen_sulfide_final_volume9_2010.pdf](https://www.epa.gov/sites/production/files/2014-11/documents/hydrogen_sulfide_final_volume9_2010.pdf).