AIR POLLUTION INJURES TREES


The main gaseous air pollutants that injure trees are sulfur dioxide, fluorides, and oxidants.

Sulfur dioxide comes mostly from burning coal and oil to generate electricity. It also is produced in smelting ores that contain sulfur and in manufacturing sulfur products.

Fluorides are produced by processing aluminum ore, manufacturing phosphate fertilizer and processing stone.

The oxidants are formed in the atmosphere from chemical reactions powered by sunlight. The oxidants that cause the most tree damage are ozone and PAN (Peroxyl Acetyl Nitrate). They are produced mostly from industrial and auto emissions, and they are common components of smog. Low concentrations of ozone also occur naturally in the atmosphere.

The most serious forms of air pollution are difficult to prevent without a community effort. Contact local environmental agencies and citizen groups to offer your help. Minimize the air pollution you produce by keeping your automobiles tuned, limiting your use of internal combustion engines, and obeying local open-burning ordinances.

Air pollution damage to trees is most common around large cities, but it can also be seen in rural areas.
These trees are relatively tolerant to common air pollutants:
  • ARBORVITAE
  • BOXELDER
  • DOUGLAS-FIR
  • ENGLISH OAK
  • MAGNOLIA
  • NORWAY MAPLE
  • RED OAK
  • WHITE DOGWOOD
  • WHITE SPRUCE

These trees are relatively intolerant to common air pollutants:
  • AMERICAN ELM
  • CATALPA
  • JACK PINE
  • LARCH
  • LOMBARDY POPLAR
  • PONDEROSA PINE
  • QUAKING ASPEN
  • VIRGINIA PINE
  • WHITE PINE
  • WILLOW

Healthy pine needles. Pollution-injured pine needles. Green and brown bands on pine needles indicate air pollution damage.

Healthy maple leaves. Pollution-injured maple leaves. Discoloration along the midrib of hardwood leaves may indicate air pollution damage.


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