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Clean Air NJ
What is Smog and How is it Formed?


Oxygen NOx VOCs Sun Ozone

How is Smog Formed?

Ground-level ozone, also known as smog, is an air pollutant known to cause a number of health effects and negatively impact air quality and the environment in the state of New Jersey.  Ozone is formed when oxides of nitrogen (NOx) and volatile organic compounds (VOCs) react in the presence of sunlight.  Smog can irritate any set of lungs, but those with lung-related deficiencies should take extra precautions on bad ozone days.

The What's Your Air Quality Today? page on this site tells you how to sign up to receive notifications and find out when your local air has reached unhealthy ozone levels.  Since each ozone episode is different, depending on a number of meteorological and air quality factors, you can find out the specifics on ozone exceedances in New Jersey’s non-attainment areas this year by clicking here.

Good v.Bad Ozone

Ozone is a gas that occurs both in the Earth's upper atmosphere and at ground level. Ozone can be "good" or "bad" for your health and the environment, depending on its location in the atmosphere. Click here to find out more.

Why is it Worse in Summer? Understanding the Link Between Weather and Ozone Formation

Smog, otherwise known as ground-level ozone, can be a summertime air pollution problem in the region, and weather plays a key role in the levels of ozone that we experience. Meteorologists and other weather professionals and enthusiasts can help educate the public about smog’s health effects, and provide tips on minimizing exposure to ozone and simple actions to take that reduce ozone formation.

Click on a presentation below to hear New Jersey’s meteorology and air quality experts talk about how to educate the public about this weather-dependent pollutant.

  • Expanding weather forecasts to address ozone health issues – Dan Zarrow, NJ101.5 Meteorologist ( PDF - MP4 )
  • How ground level ozone is formed — Ann Marie Carlton, Rutgers Atmospheric Chemist ( PDF - MP4 )
  • Weather trends and hot summer days – Dave Robinson, NJ State Climatologist/Rutgers ( PDF - WMV )
  • Health effects of ozone — Kevin Stewart, American Lung Association of the Mid-Atlantic Environmental Director (a longer presentation from Mr. Stewart with more details on ozone’s health effects can be found here.) ( PDF - MP4 )
  • NJDEP’s Ozone Forecasting - Greg John, NJDEP ( PDF - WMV )

The opinions and information contained in these presentations are solely those of the original author and as such, do not necessarily reflect the official policy or position of NJDEP or the State of New Jersey.