Busy streets next to parks, childcare centers, and schools are often concerning, particularly when it comes to exposing young children to air pollution that can harm their developing brain.
This concern prompted Tempe city staff to collaborate with Arizona State University Professor Jenni Vanos to measure air pollution concentrations in green spaces located near busy streets. The team wanted to know if desert-specific plants could reduce air pollutant concentrations in spaces used by kids through the dense planting—otherwise known as vegetative barriers—that captures pollutants with its leaves.
LEVERAGING VEGETATION TO REDUCE POLLUTION
Hedge and shrub characteristics that reduce air pollution are dense hedge canopy, smaller leaf size, complex leaf shape, stiffer leaf structure, waxy or hairy leaf surface, longevity of leaves (i.e., evergreen), and high leaf area density and leaf area index. Hedge heights of at least 6 feet are needed to significantly reduce air pollution exposures.
“Using strategically-placed and selected vegetation may help lower exposures, especially next to busy roadways, to help prevent health issues for children. As a new mother, this work has an even higher level of urgency. It’s necessary for us all to work together to reduce neurotoxic exposures for all the children of Tempe,” said Dr. Vanos.
Dr. Vanos and her students collected air quality data—PM2.5 (i.e., particulates <2.5m in diameter) and nitrogen dioxide (NO2)—using eight networked, low-cost air quality sensors by Clarity, Inc. The team is working on a peer-reviewed publication that shares examples from around the world of passive green barriers, and describes the data collection process.
PLANT MITIGATION GUIDE FOR RESIDENTS OF SOUTHWESTERN CITIES
While the air quality monitoring was underway, Tempe staff and ASU partners collaborated to develop a Plant Mitigation Guide that rates the ability of desert plants to reduce air pollution.
The plant guide is an easy to use and practical guide to the plants Tempe residents can use to shade their homes and yards while improving their local air quality. It's an awesome, evidenced-based guide to healthier outdoor spaces for our children.
ENGAGING THE COMMUNITY IS KEY
Community members were invited to a free native plant and shrub give-away early this year organized by Tempe’s Sustainability and Resilience Office to learn about these efforts. Families with kids under 3 years old were allowed to select two free plants from an assortment of available fruit trees, native trees and shrubs. Staff chatted with parents about how trees and shrubs can support healthy babies and children through better local air quality.
Practical information about reducing exposures to chemicals at home were shared too. Feel free to share with your residents too: “5 Baby Foods with Arsenic and Lead – Safer Choices and 10 Steps for Healthy Water for Your Babies
WHAT COMES NEXT?
The City of Tempe has allocated funds to invest more in urban forestry, green stormwater infrastructure and school greening projects. The lessons learned from this project and the plant guide will be used to inform what trees and shrubs we plant throughout the city. The City is also embarking on a Resilient Tempe Master Plan and Feasibility Study to create a 25-year vision for green stormwater infrastructure, urban cooling and urban forestry. This plan will support creating a more shaded city with better air quality that is healthier for babies and children.
Would your city like to learn more about Tempe's work? Contact Dr. Jenni Vanos, Arizona State University Professor at Jenni.Vanos@asu.edu.
Is your city interested in being part of Healthy Babies Bright Futures’ Bright Cities program? To discuss this and anything else, please contact Bright Cities Program Director, Kyra Naumoff Shields at email@example.com.