Nitrogen is a highly reactive element that can form various oxides, each with its own characteristics and properties. Here are some notable oxides of nitrogen:

1. Nitric Oxide (NO): This is a relatively unstable oxide that is colorless and odorless. It is produced naturally during the combustion of fossil fuels and in certain biological processes. Nitric oxide is involved in several important physiological functions, such as regulating blood pressure and acting as a signaling molecule.

2. Nitrogen Dioxide (NO2): Nitrogen dioxide is a pungent, reddish-brown gas with a strong odor. It is also produced during combustion processes and can be a significant contributor to air pollution. Nitrogen dioxide is a respiratory irritant and can cause adverse effects on human health.

3. Nitrous Oxide (N2O): Also known as laughing gas, nitrous oxide is a colorless gas that has a sweet, slightly intoxicating odor. It has been used as a recreational drug and as an anesthetic in medical settings. Nitrous oxide is a greenhouse gas and can have negative environmental impacts.

4. Nitrogen Trioxide (NO3): This oxide is a blue gas that is highly reactive and unstable. It is not commonly found in significant amounts in the atmosphere.

5. Nitrogen Pentoxide (N2O5): Nitrogen pentoxide is a white crystalline solid that is extremely unstable and reactive. It is a powerful oxidizing agent and can react explosively with certain compounds.

6. Nitrous Acid (HNO2): This is an unstable, colorless acid that can be produced through the reaction of nitrogen dioxide with water. It is an intermediate in some industrial processes and is also present in the form of salts, such as sodium nitrite.

7. Nitric Acid (HNO3): Nitric acid is a highly corrosive, colorless, and pungent liquid that is one of the most important industrial acids. It is used in the production of various explosives, fertilizers, plastics, and other chemicals.

These oxides of nitrogen exhibit different chemical properties and have various roles in atmospheric chemistry, environmental impact, and industrial applications. The emissions and concentrations of these compounds are monitored and regulated due to their potential effects on air quality and human health.