Nitrogen Dioxide has both human and environmental effects.

Human effects: Breathing air with a high concentration of NO2 can irritate airways in the human respiratory system. Short exposure to NO2 can aggravate respiratory diseases, leading to coughing, wheezing, and hospital admissions. Longer exposure can lead to severe respiratory problems, such as lung cancer.

Environmental effects: Nitrogen oxides are molecules made of nitrogen and oxygen atoms. These nitrogen oxides contribute to air pollution problems such as acid rain (which harms lakes and forests), visibility/haze (which makes it more difficult to see outdoors), and nutrient pollution (which causes air and water to become polluted/contaminated).