Metal oxide semiconductors in detecting environmentally important gases

3 Metal oxide semiconductors in detecting environmentally important gases 

In this section we review the use of metal oxide semiconductor gas sensors for the detection of environmentally important gases such as carbon monoxide, carbon dioxide, ammonia and nitrous oxides. 

Carbon monoxide concentration (ppm) COwb level (%) Signs and symptoms 

200 20 Slight headache within 2 to 3 hours loss of judgement 

800 30 Dizziness, nausea and convulsions within 45 minutes, insensible within 2 hours 

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