Ground-level (tropospheric) ozone ( $O3\text{O}_3$ ) is a major greenhouse gas and air pollutant that contributes to photochemical smog. Which of the following describes the primary chemical pathway responsible for the formation of tropospheric ozone in Earth's atmosphere?

The direct emission of ozone as a primary product during the high-temperature combustion of fossil fuels in vehicle engines.

The photolysis of nitrogen dioxide ( $NO2\text{NO}_2$ ) by sunlight, releasing reactive oxygen atoms that combine with molecular oxygen ( $O2\text{O}_2$ ).

The catalytic oxidation of sulfur dioxide ( $SO2\text{SO}_2$ ) by atmospheric water vapour and oxygen under ultraviolet radiation.

The anaerobic decomposition of agricultural organic matter, releasing volatile organic compounds that directly isomerise into ozone.

The direct emission of ozone as a primary product during the high-temperature combustion of fossil fuels in vehicle engines.

The photolysis of nitrogen dioxide ( $NO2\text{NO}_2$ ) by sunlight, releasing reactive oxygen atoms that combine with molecular oxygen ( $O2\text{O}_2$ ).

The catalytic oxidation of sulfur dioxide ( $SO2\text{SO}_2$ ) by atmospheric water vapour and oxygen under ultraviolet radiation.

The anaerobic decomposition of agricultural organic matter, releasing volatile organic compounds that directly isomerise into ozone.

Interpreting and interacting with earth systems

Question 6

Markscheme

Interpreting and interacting with earth systems

Question 6

Markscheme

Interpreting and interacting with earth systems

Question 6

Interpreting and interacting with earth systems Questions

Interpreting and interacting with earth systems

Question 6

Interpreting and interacting with earth systems Questions