What are the different methods for detecting toxic gases in industrial environments?

Toxic gas detection methods: Electrochemical sensors (specific reactions generate current proportional to concentration - H2S, CO, Cl2), Semiconductor/MOS (resistance changes with gas absorption - general hydrocarbon detection), Photoionization (UV ionizes compounds, measures current - VOCs, ppb sensitivity), Infrared (absorption measurement - specific gases), and Colorimetric tubes (color change indicates concentration - spot checks). Selection factors: target gas, concentration range, response time, cross-sensitivity, environmental conditions, and maintenance requirements. Many industrial applications use electrochemical sensors for common toxic gases.