Infrared band-pass filters are designed to detect and measure gases in the atmosphere. Many gases show specific absorption lines in the mid-to far-infrared range. The gas concentration can be measured using a filter that allows monitoring of the uptake of this particular gas. Application: mainly used in infrared optical smoke and dust concentration online monitoring equipment, pollution source smoke and dust emission monitoring, dust concentration monitoring in industrial manufacturing, dust load monitoring equipment in production workshops, etc. Detection gas type Central wavelength (μm) Transmittance(%) Semi-wide band (μm) Depth of cutoff C2H2 13 85 0.09/0.14 OD3…