Answer:To decrease carbon monoxide production oxygen is added to the combustion process.
Explanation: Carbon Monoxide(CO) is a type of harmful gas that is produced when there is a incomplete combustion of carbon. It is in odorless and poisonous/toxic form . Due to the less amount of oxygen there is incomplete combustion , so if there is more supply of oxygen the result will be a complete combustion and this would decrease the production of carbon monoxide.