Which of the following is a consequence of NOx emissions?

The correct answer is related to the formation of greenhouse gases as a consequence of NOx emissions. Nitrogen oxides (NOx) are pollutants produced from combustion processes, such as those found in vehicles and power plants. When released into the atmosphere, NOx can contribute to the formation of ozone and particulate matter, both of which play a role in climate change.

Specifically, NOx emissions can lead to the creation of secondary pollutants that act like greenhouse gases, enhancing the greenhouse effect. This occurs because these secondary pollutants can trap heat in the atmosphere, leading to global warming. Reducing NOx emissions is therefore a key part of strategies aimed at mitigating climate change.

Other options, such as reduction of energy efficiency, increased water purity, and improved plant growth, do not directly relate to the primary consequences of NOx emissions. While it is true that NOx can have various environmental impacts, including effects on energy efficiency and ecosystem health, the most straightforward and significant consequence concerning climate change is the formation of greenhouse gases.