What is the primary anthropogenic source of nitrogen oxides (NOx\text{NO}_xNOx, representing NO\text{NO}NO and NO2\text{NO}_2NO2) in the troposphere?
Microbial denitrification of synthetic nitrogen fertilizers in agricultural soils
High-temperature reaction of atmospheric nitrogen and oxygen in internal combustion engines
Anaerobic decay of organic matter in waterlogged soils and municipal landfill sites
Incomplete combustion of carbonaceous fuels under restricted oxygen supply
32 exam-style questions on OCR GCSE Chemistry Interpreting and interacting with earth systems. Each one has a worked solution and a mark scheme showing where the marks go.