Which of the following emissions is NOT considered a gaseous pollutant?

Nitrogen is primarily considered a non-toxic, inert gas that makes up about 78% of the Earth’s atmosphere. While it is found in large quantities in the air, it does not contribute to pollution or environmental degradation in the same way that the other options do.

Methane, on the other hand, is a potent greenhouse gas that has a significant effect on global warming and is classified as a gaseous pollutant. Sulphur oxides are produced from the burning of fossil fuels and can lead to acid rain and serious respiratory issues. Carbon monoxide is a harmful gas produced from incomplete combustion of fossil fuels and is detrimental to air quality and human health.

Thus, nitrogen is not considered a gaseous pollutant like methane, sulphur oxides, or carbon monoxide, which are involved in environmental and health-related issues.