What are oxides of nitrogen, and how do they contribute to acid rain?

Oxides of nitrogen are compounds formed when nitrogen reacts with oxygen at high temperatures, such as in vehicle engines. They contribute to acid rain by reacting with water vapor in the atmosphere to form nitric acid, which falls as acid rain.

A strong answer should directly address the approved learning objective to explain that oxides of nitrogen can cause acid rain. This question belongs to Properties and effects of atmospheric pollutants within Common atmospheric pollutants and their sources, so the response should use that exact curriculum context rather than a generic statement. The answer is correct when it names the key idea, explains the link to acid rain, and keeps the wording specific to AQA GCSE revision.