By particle size, filters pollutants, using diameter 47 mm 3 and install it into the tunnel through the exhaust sample dilution dilution (Dilution Tunnel) vault, for example, is made of material that does not rust.
The size of filter pollutants particle diameter were used 47 mm 3 series and installed into the sample dilution tunnel exhaust through the dilution. (Dilution Tunnel) series samples made from materials that do not rust