1. Compare, e.g., air protection plans and exhaust gas standards as stipulated by national and international legislation.
2. Compare data published by the European Industrial Gases Association under https://www.eiga.eu/
3. Environmental Health Criteria 213 CARBON MONOXIDE (SECOND EDITION), World Health Organization Geneva, 1999, http://apps.who.int/iris/bitstream/10665/42180/1/WHO_EHC_213.pdf
4. High-temperature ceramic gas sensors: a review;Akbar;Int. J. Appl. Ceram. Technol.,2006