Researchers at the University of Houston have determined that climate change -- in the form of a stronger sea breeze, the result of warmer soil temperatures -- contributed to the drop in high-ozone days in the Houston area.
Robert Talbot, professor of atmospheric chemistry, said that also should be true for coastal regions globally.
The researchers describe their findings in a paper published this week in the journal Atmosphere. In addition to Talbot, they include first author Lei Liu, a doctoral student, and post-doctoral fellow Xin Lan.
Researchers at the University of Houston have determined that climate change -- in the form of a stronger sea breeze, the result of warmer soil temperatures -- contributed to the drop in high-ozone days in the Houston area.
Robert Talbot, professor of atmospheric chemistry, said that also should be true for coastal regions globally.
The researchers describe their findings in a paper published this week in the journal Atmosphere. In addition to Talbot, they include first author Lei Liu, a doctoral student, and post-doctoral fellow Xin Lan.
The study relied upon ground-level ozone data collected over the past 23 years by the Texas Commission on Environmental Quality. The meteorological data was collected by the National Oceanic and Atmospheric Administration.
The researchers said they did not set out to find a connection between climate change and lower ozone levels -- the number of days in which ozone levels exceeded federal standards varied from year to year but overall, dropped dramatically between 1990 and 2013. For example, in Aldine, one of four sites studied, the number of days during which ozone levels exceeded federal standards over an eight-hour period dropped to an average of 11 days per year during 2001-2013, down from 35 days per year during 1990-2000.
Talbot said the steep decline made him suspect something was happening beyond a city-led effort to reduce nitrogen oxide emissions, one of the components of ozone.
Liu said they first ruled out other meteorological factors, including temperature, humidity and solar radiation. After they discovered the lower ozone readings coincided with days the southerly flow was strongest, they realized that climate change -- in the form of warmer soil temperatures -- had increased the southerly flow, she said.
Houston skyline image via Shutterstock.
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