For all of the questions I get on a seemingly regular basis about the impact of air pollution on urban gardens, there is surprisingly little research that has been done on the topic. What we do know undeniably is that some plants are more sensitive to air pollution and ozone than others. Though not true of every plant, air pollution in the garden can present itself in the form of brown spots and leaf discoloration that is caused by ozone entering the plant and oxidizing its tissues.
It is also speculated (though not proven as there have been no studies of which I am aware) that air pollution leads to smaller and less vibrant plants with a lesser yield than similar plants grown without air pollution.
If you live in an area that you suspect may have air pollution issues, there are several things you can do to handle produce grown in areas with air pollution:
- Remove the outermost leaves of vegetables with layers (like cabbage).
- Wash and peel fruits and vegetables before use.
- Wash root vegetables (it is not necessary to peel them in most cases).
The American Geosciences Institute has a tutorial aimed at grades 6-9 that teaches kids how to create an ozone garden to monitor the effects of excessive ozone on plants. The information is useful for adults as well.
- Using Sensitive Plants as Bioindicators of Ground Level Ozone Pollution
Dr. Irene Ladd & Susan Sachs
- List of Ozone Bioindicators
from The National Park Service