1．Formation of ____________ results from incomplete combustion of fuel and is caused by a rich fuel mixture or lack of air mass.
WPS
QC
HC
CO
2．Particulate matter (PM) is partly burnt fuel associated mainly with diesel engines, and is also formed by the reaction between other pollutants.
对
错
3．carbon dioxide (CO2)
一氧化物
氧化物
二氧化碳
颗粒物质
