The samplers take readings at hourly intervals. EPA's health-based national air quality standard for NO 2 is 0.053 ppm, measured as an annual arithmetic mean concentration. Health and other effects of NO 2 Irritate eyes and nose Increase susceptibility to influenza. Cause visible leaf damage and stunt plant growth. Create brown haze.
Ozone is a reactive form of oxygen.
It is the prime ingredient of smog in our cities. When these compounds react with heat and sunlight, it forms ozone. Ground-level ozone forms readily in the atmosphere, especially during hot weather. Nitrogen oxides are emitted from motor vehicles, power plants, and other sources of combustion. Ozone concentrations can vary from year to year due to changing weather patterns.