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.
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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.
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