How are nitrogen oxides formed?

Nitrogen oxides, which include nitric oxide (NO) and nitrogen dioxide (NO2), are primarily produced during high-temperature combustion processes. When temperatures exceed approximately 538 degrees Celsius (1000 degrees Fahrenheit), the nitrogen in the atmosphere reacts with oxygen, leading to the formation of these oxides. This process is particularly significant in environments like car engines and power plants, where high temperatures are commonplace.

The other options do not accurately describe the formation of nitrogen oxides. For instance, the evaporation of water in the atmosphere and the decomposition of organic matter pertain to different processes that do not involve the specific chemical reactions necessary for nitrogen oxides to form. Similarly, while sulfur and oxygen react to form sulfur oxides, this is unrelated to the nitrogen oxides discussed in this context. Thus, the correct understanding is rooted in recognizing the role of high temperatures in driving the chemical reactions that produce nitrogen oxides.