The other limit values have safety margins built into them and so an exceedence does not necessarily mean a health consequence. The 2 ppm limit value is associated with bronchial effects in some sensitive asthmatics and so should not be exceeded. Table 2: The Department recommended H 2S exposure limits for public protection Limit (ppm)ДЄveraging timeframe is the time over which the measured level of hydrogen sulfide in air is averaged and relates to potential short or possibly longer term effects. 1 These are based on the dose exposure effects outlined above. The Western Australian Department of Health recommends hydrogen sulfide air quality guidelines developed by the World Health Organization as shown in Table 2. Are there exposure guidelines for hydrogen sulfide? Levels in air However, care should be taken since children are lower to the ground where hydrogen sulfide may be more concentrated and active children may breathe in more of the gas. It is not clear whether children are more sensitive than adults to hydrogen sulfide although they are likely to show the same types of effects. Neurological effects including memory loss and dizziness Increasing possibility of annoyance and headache, nausea, fatigue Odour threshold (with some individual variability) Exposure and effect levels for hydrogen sulfide in air. The impacts and health effects of exposure to the levels of hydrogen sulfide that may be possible in the environment are shown in the Table 1. The lowest level for adverse health effects is at least 500 times the odour detection limit.ДЄt this level, irritation of the mucous membranes of the eye can occur. Real human impacts from hydrogen sulfide are not likely until air levels reach at least 2 ppm for 30 minutes.ДЄt this point sensitive groups such as some asthmatics may respond with some minor irritative changes in their bronchial capacity. Although these are not direct health effects they are undesirable. Repeated odour events may culminate in real symptoms such as headache, fatigue and nausea. The smell can cause worry, anxiety and resentment. Smelling hydrogen sulfide does not mean that it will harm your health. Hydrogen sulfide has a characteristic rotten egg smell which can be detected at very low levels, well below those that are known to cause health effects. Therefore exposure is only likely to continue if there is an ongoing source. Hydrogen sulfide usually breaks down in air in about 3 days and is dispersed by wind. People are normally exposed to hydrogen sulfide in air by breathing it in or by skin/eye contact.ДЄny absorbed hydrogen sulfide does not accumulate in the body as it is rapidly metabolised in the liver and excreted in the urine. This may especially be the case where acid sulfate soils have been disturbed. Hydrogen sulfide has also been found to contaminate bore water and surface water bodies, usually at low levels, due to bacteria which convert sulfur materials into hydrogen sulfide. In Western Australia some coastal communities have been exposed to hydrogen sulfide generated by the breakdown of seaweed that has accumulated on the shore line.

Human activities and industries that may produce hydrogen sulfide include: Hydrogen sulfide occurs naturally in some environments such as sulfur springs, swamps and salt marshes, and is often associated with the decomposition of organic material. Hydrogen sulfide (H 2S) is a colourless gas with a characteristic odour of rotten eggs which being denser than air may pool in low areas in still conditions.