What is the maximum safe concentration of H2S in air before it becomes dangerous?

Hydrogen sulfide (H2S) is a highly toxic gas that poses serious health risks even at relatively low concentrations. The correct answer identifies 150 ppm as the maximum safe concentration at which H2S can be present before significant health effects begin to occur. At levels around this concentration, exposure can lead to respiratory irritation and other adverse effects.

Regulatory bodies and health organizations often establish permissible exposure limits to protect workers and the general public from the dangers associated with H2S. The threshold of 150 ppm is commonly noted as a critical level, above which immediate protective measures need to be taken.

Understanding these concentration levels is essential for environmental compliance inspectors, as they assess air quality and ensure that workplaces and public areas adhere to safety regulations. Recognizing this specific threshold helps inspectors identify potential hazards and implement appropriate safety protocols to mitigate risks associated with H2S exposure.