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Hydrogen Sulfide

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A draft page for collecting and organizing information, questions, and projects related to hydrogen sulfide, also known as H2S.

Hydrogen sulfide is a colorless, flammable, extremely hazardous gas with a “rotten egg” smell. It occurs naturally in crude petroleum and natural gas, and can be produced by the breakdown of organic matter and human/ animal wastes (e.g., sewage). It is heavier than air and can collect in low-lying and enclosed, poorly ventilated areas such as basements, manholes, sewer lines and underground telephone/electrical vaults. (via OSHA.gov)


Framing the problem

  • Where is this an issue?
  • Who's working on this already?
  • What information is missing, if any? How will it change the situation?
  • What are they key parameters:
    • What intensities & exposure times are harmful to humans or the environment?
    • Where and how can it be detected? by smell range?
    • How long does it take to detect?
    • How fast does it move/change, or how large an area does it affect?
    • What kind of detection? presence/absence? direction of flow? intensity or locating a spot source?
  • What should the output data look like? Graphs, logs, lights, images?
  • What are the data’s uses/outcomes? Legal? Avoidance? Remediation? Regulation?

Where is this an issue?

Here I've (@warren) collected some of the notes folks have posted on PublicLab.org about where H2S has been a problem, under the tag #h2s-sites :


Post more on H2S sites - help build out this list by posting your own notes on H2S-affected sites


Detecting H2S

Wikipedia's article, which is pretty well referenced, shows that:

0.00047 ppm or 0.47 ppb is the odor threshold, the point at which 50% of a human panel can detect the presence of an odor without being able to identify it.

This seems to be well below what's cited as a risk to health, but OSHA warns not to use smell as a means to detect it (OSHA.gov):

Can be smelled at low levels, but with continuous lowlevel exposure or at higher concentrations you lose your ability to smell the gas even though it is still present. At high concentrations – your ability to smell the gas can be lost instantly. DO NOT depend on your sense of smell for indicating the continuing presence of this gas or for warning of hazardous concentrations.

Most info I've (@warren) compiled here shows 10+ parts per million as when health effects are of concern, but one cites a TWA (time weighted average) of 1ppm -- over 8 hours. See below in the health effects section.

Questions about detection

Some questions to begin with include:

  • What equipment is available today, and who has access to it? How much does it cost and what is its sensitivity/latency? How much does it weigh and how does it work (air grab sample, continuous flow, soil sample?)
  • Are there alternative means of detecting which are dramatically different/cheaper?
    • silver film tarnishes with exposure to H2S, some sources cite discolored copper coins in someone's pocket as a way to diagnose a high exposure

We're collecting questions about H2S detection - please add your own here:

Title Author Updated Likes Comments
What are good humidity sensor/monitors to use with gas sampling kits? @gretchengehrke over 6 years ago 2
How to select a site for hydrogen sulfide testing? @warren over 6 years ago 3
How can we safely try out and evaluate a hydrogen sulfide test? @warren over 6 years ago 4
Can copper sulfide and copper oxide products be precisely visually identified? @gretchengehrke over 6 years ago 5
Can we determine hydrogen sulfide concentration, or a threshold presence/absence using the copper pipe method? @gretchengehrke over 6 years ago 0
What is the hydrogen sulfide concentration range that can be monitored using a copper tarnish method? @gretchengehrke over 6 years ago 1
What are the relative rates of hydrogen sulfide oxidation in ambient air? @gretchengehrke almost 7 years ago 1
Methods for or experience measuring workplace hydrogen sulfide gas? @gretchengehrke almost 7 years ago 2
Interest in Hidrogen Sulfide Sensing @fernandolunav almost 12 years ago 3


Health effects

Health effects vary with how long, and at what level, you are exposed. Asthmatics may be at greater risk. Low concentrations – irritation of eyes, nose, throat, or respiratory system; effects can be delayed. Moderate concentrations – more severe eye and respiratory effects, headache, dizziness, nausea, coughing, vomiting and difficulty breathing. High concentrations – shock, convulsions, unable to breathe, coma, death; effects can be extremely rapid (within a few breaths).

(Exposure information from OSHA.gov)

Exposure limits from various sources, from an Airgas Materials Safety Data Sheet:

ACGIH TLV (United States, 3/2016).
 STEL: 5 ppm 15 minutes.
 TWA: 1 ppm 8 hours.
NIOSH REL (United States, 10/2013).
 CEIL: 15 mg/m³ 10 minutes.
 CEIL: 10 ppm 10 minutes.
OSHA PEL 1989 (United States, 3/1989).
 STEL: 21 mg/m³ 15 minutes.
 STEL: 15 ppm 15 minutes.
 TWA: 14 mg/m³ 8 hours.
 TWA: 10 ppm 8 hours.
OSHA PEL Z2 (United States, 2/2013).
 AMP: 50 ppm 10 minutes.
 CEIL: 20 ppm

Note that these show toxicity at levels close to the ability of the wearable electronic monitors (see above) can detect -- 10-15ppm; "STEL" means Short Term Exposure Limit, or an "acceptable average exposure over a short period of time."

Questions

Please ask questions to help us expand this set of resources:

Title Author Updated Likes Comments
What are good humidity sensor/monitors to use with gas sampling kits? @gretchengehrke over 6 years ago 2
How to select a site for hydrogen sulfide testing? @warren over 6 years ago 3
How can we safely try out and evaluate a hydrogen sulfide test? @warren over 6 years ago 4
Can copper sulfide and copper oxide products be precisely visually identified? @gretchengehrke over 6 years ago 5
Can we determine hydrogen sulfide concentration, or a threshold presence/absence using the copper pipe method? @gretchengehrke over 6 years ago 0
What is the hydrogen sulfide concentration range that can be monitored using a copper tarnish method? @gretchengehrke over 6 years ago 1
What are the relative rates of hydrogen sulfide oxidation in ambient air? @gretchengehrke almost 7 years ago 1
Methods for or experience measuring workplace hydrogen sulfide gas? @gretchengehrke almost 7 years ago 2
Interest in Hidrogen Sulfide Sensing @fernandolunav almost 12 years ago 3

Existing work on Public Lab.org

A range of projects related to H2S have been developed here over the years; we're going to try to organize it better, but for now:

Title Author Updated Likes Comments
Detect Hydrogen Sulfide (Fart ) in Public Toilets with Arduino UNO/NodeMCU(ESP8266) @silentsairam about 5 years ago 3
Response to Alternative Copper Sheet Preparation Method on Public Lab @ErikHanley11 over 6 years ago 0
Qualitative Time Lapse of Copper Corrosion @ErikHanley11 over 6 years ago 4
Two Rounds of Copper Rod Test Making @ErikHanley11 over 6 years ago 3
Copper Strip Test Preparation Using Solvents @ErikHanley11 over 6 years ago 1
Copper Rod to Copper Sheet Discussion @ErikHanley11 over 6 years ago 0
What are some options for copper materials to make a copper plate test kit? @warren over 6 years ago 3
What are different commercially available hydrogen sulfide detection methods? @warren over 6 years ago 3
How to select a site for hydrogen sulfide testing? @warren over 6 years ago 3
How can we safely try out and evaluate a hydrogen sulfide test? @warren over 6 years ago 4
Training in odor identification? @sara over 6 years ago 1
What's the best setup for a copper rod or copper plate test for DIY hydrogen sulfide detection? @warren over 6 years ago 6
Can copper sulfide and copper oxide products be precisely visually identified? @gretchengehrke over 6 years ago 5
How quickly do copper sulfide and copper oxide form under different environmental conditions? @gretchengehrke over 6 years ago 0
What is the hydrogen sulfide concentration range that can be monitored using a copper tarnish method? @gretchengehrke over 6 years ago 1
What methods are available for doing air grab samples for hydrogen sulfide? @stevie almost 7 years ago 2
Hydrogen sulfide badges by Morphix Technologies @gretchengehrke almost 7 years ago 1
What are the reaction rates of hydrogen sulfide with oxygen versus copper or silver? @gretchengehrke almost 7 years ago 0
What are the relative rates of hydrogen sulfide oxidation in ambient air? @gretchengehrke almost 7 years ago 1
Methods for or experience measuring workplace hydrogen sulfide gas? @gretchengehrke almost 7 years ago 2
Article on monitoring hydrogen sulfide with a copper pipe @warren about 7 years ago 0
My DIY Formaldehyde test kit @mathew about 9 years ago 6
Preparation for Pilot H2S Testing @ErikHanley11 about 9 years ago 0
using soap bubbles for pump calibration @mathew about 9 years ago 21