Feature

Ozone Monitoring Made Easy
11.30.06
A small garden
To measure ozone in the Earth's atmosphere, NASA built the approximately 6,500-pound Aura satellite. The spacecraft carries four high-tech instruments that scan the globe from more than 700 kilometers above the planet.

Image to right: The ozone garden at Goddard Space Flight Center is full of plants that scientists have found to be ozone-sensitive. Credit: NASA

For students, there is an easy way to monitor ozone in their own neighborhood. It's as simple as growing a few carefully selected plants. Scientists at NASA's Goddard Space Flight Center in Greenbelt, Md., are showing how this can be done. They've installed an ozone-monitoring garden outside the Goddard visitor center.

A diagram showing how sunlight affects nitrogen oxides and volatile organic compounds to create ground-level ozone
Ozone, a molecule made up of three oxygen atoms, can be both good and bad. Good ozone is found high up in the atmosphere -- in the stratosphere -- where it occurs naturally and protects humans and other living things from the sun's harmful ultraviolet rays. Bad ozone forms in the lower atmosphere -- in the troposphere -- when pollution from cars, trucks, factories and other manmade sources interacts with sunlight.

Image to left: High concentrations of ozone found in the Earth's lower atmosphere are hazardous to life. Credit: NASA

Too much tropospheric ozone makes air unhealthy for people to breathe. Some plants are also sensitive to ozone, which enters plants through tiny pores in a leaf's outer layer. When exposed to high levels of the gas for extended periods of time, leaves on these plants may develop small colored spots or turn yellow, and reduced photosynthesis may hinder overall plant growth.

Related Resources
+ Goddard Ozone Monitoring Garden

+ ChemMatters: Aura Launches! (pdf)

+ MY NASA DATA: Trouble in the Troposphere -- A Lesson on Tropospheric Ozone
Goddard's ozone garden contains several types of ozone-sensitive plants: the black-eyed Susan, cut-leaf coneflower, flowering dogwood and snap beans. The garden is meant to educate the public, including school groups that visit Goddard, about ozone in the atmosphere. Students anywhere can monitor ozone by looking in their neighborhoods for ozone-damaged plants, and by making similar gardens outside their school or in their own backyard.

Many U.S. cities are working hard to reduce ozone pollution. Students and adults can help by walking, carpooling, or taking public transportation, thus limiting the number of vehicles on the road and pollution in the air. Other helpful steps include turning off lights and appliances not in use, and cutting back on heating and air conditioning.

A discolored leaf of a black-eyed Susan plant affected by ozone
Image to left: Plants with ozone damage have very fine colored spots on the upper surfaces of their leaves. Some leaves also turn yellow. Credit: NASA

How's your city doing? Build an ozone garden and find out!





Additional Information
Aura monitors ozone and other gases at all levels of the atmosphere. The satellite consists of four instruments -- two radiometers and two spectrometers -- that each look down on Earth from a different angle. Together, these instruments are able to capture a complete view of the sky, from top to bottom.

How do Aura's instruments estimate ozone? They measure specific frequencies of energy absorbed and emitted by the Earth's atmosphere in the form of heat and light. Because the various gases in the atmosphere absorb and emit energy at different wavelengths, ozone can be identified by looking for a particular pattern of absorption and emission.

NASA is committed to building strategic partnerships and linkages between science, technology, engineering and mathematics formal and informal educators. Through hands-on, interactive educational activities, NASA is engaging students, educators, families, the general public and all agency stakeholders to increase Americans' science and technology literacy.

Dan Stillman, Institute for Global Environmental Strategies