National Aeronautics and Space Administration

Signs of ozone damage

• Tiny, evenly spaced purple or black dots (known as stippling). Stippling occurs
  • on upper surface of leaf only
  • not in the veins of the leaf
  • more on the lower, older leaves
• Yellowing (known as chlorosis). Note that chlorosis may occur for reasons other than ozone over-exposure.
• Eventually leaves that accumulate enough ozone damage die and fall off. However, not all injury to plant leaves are a result of ozone damage. For a list of known ozone-sensitive species, please visit the National Park Service, Ozone Bioindicators website.

Ozone damage on a red oak (Quercus rubra) leaf. Shennandoah National Park, VA, June 2006. Ozone damage on red raspberry (Rubus strigosus) leaves. Pictured Rocks National Lakeshore, Munising, MI. July, 2006.

Cutleaf coneflower (Rudbeckia laciniata) exhibitng ozone damage. NASA/Goddard Space Flight Center, Greenbelt, MD, July 2006.

Ozone damage on common blackberry (Rubus allegheniensis). White pine (Pinus strobes) showing ozone damage on needles.