Trees and Air Quality

How do we love thee, tree? Let us count the ways...

Tall tree with moss
There are numerous benefits to planting trees including conserving energy, providing shade and cooling, filtering and retaining stormwater, screening for privacy, enhancing views, providing habitat for wildlife, and creating oxygen that supports the lives of many species on Earth, including humans. Studies indicate that over a period of one year, an acre of mature trees can provide enough oxygen for 18 people to breathe.

While some trees emit large amounts of volatile organic compounds (VOCs) that contribute to the formation of ground-level ozone air pollution, overall trees remove pollution from the air and reduce energy demand. When trees are placed strategically around a home, they can cut summer air conditioning needs significantly.

Trees can increase property values by as much as 15 percent. They help to block unsightly views and can muffle sounds from nearby streets. Trees absorb dust, block wind, sooth the eye and heal the body and spirit. Studies have shown that patients with views of trees out their windows actually heal faster and with less complications. 

It is easy to see why we need more trees in our community. When it is time to select a new tree to plant, there are many characteristics to consider while making that decision such as: 

  • How tall will the tree get? 
  • What will the canopy size be when it is mature? 
  • How thirsty is the tree and will it bother people who have allergies?  
  • Is the tree native to the Sonoran Desert?
  • Does the tree emit high levels of VOCs that may contribute to the creation of ground-level ozone?   

Tall Bare TreesThese questions can be answered using an "Urban Tree Selection List" that was created by Maricopa County Air Quality Department after researching information from the Desert Botanical Garden and many other organizations.

Enough similarities exist between Pima and Maricopa counties that this tree selection list is applicable for the greater metropolitan Tucson area. If possible, avoid the "high VOC-emitting" trees to help reduce emissions that form ground-level ozone air pollution. 

Local tree-planting guidance and low cost trees can be obtained from the non-profit Tucson Clean and Beautiful's "Trees for Tucson" program. Call (520) 791-3109 for information.