How sulfate causes air in Texas' Gulf of Mexico coast to be more polluted

You might want to be careful the next time you're out on the beach, as new research suggests the air along the Gulf of Mexico coast in Texas can be more polluted.

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According to a report from the University of Houston (UH) this is because of "the highly processed and acidic chemical components of a particular matter, which are microscopic solid or liquid particles in the air." 

The report cites a new study, led by Shan Zhao, research assistant professor of atmospheric chemistry, which was in turn, published in the Environmental Science & Technology journal. 

"We found that ocean air was hazier and more polluted than the land breeze," Dr. Zhao told UH. "The next question we had was why is it not clean?" 

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The answer? Dr. Zhao, who is the first and corresponding author of the study, explained part of it is manmade. 

"We concluded the microscopic particles known as particulate matter or aerosols from the Gulf of Mexico contain high concentrations of sulfate, which originates from anthropogenic (human-generated) shipping emissions," she said. "The emissions likely pump a lot of chemicals over the gulf and with a strong sea breeze, it brings that polluted air to land." 

Other factors, UH said citing the Environmental Protection Agency (EPA), are caused by meteorological conditions, additionally, such as high sunlight intensity, temperature as well as "enhanced air humidity provided a favorable environment for chemical reactions that formed secondary aerosols, which can be harmful to your lungs and heart."

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Researchers spent several weeks collecting atmospheric data from Corpus Christi and San Antonio. The former is because UH says Corpus Christi is "understudied in atmospheric chemistry literature compared to other regions like Houston-Galveston." 

Additionally, there are only a handful of studies investigating the composition of matter originating in the Gulf of Mexico and traveling into the region. 

The most abundant component researchers found in the data they collected was Sulfate. 

"The authors write that this observation points to a strong anthropogenic influence on sulfur sources over the Gulf of Mexico," UH explained in its report. "The Gulf is one of the busiest maritime transport regions with 11 of the 15 busiest water ports in the U.S. located along its shores, one of them being the Port of Corpus Christi. Large commercial vessels typically burn fuel oil and this can produce sulfur oxides."


In fact, UH noted the emissions over the Gulf of Mexico explain about 78% of the total sulfate in the air. Combined with pollutant chemicals, humidity essentially makes for the most ideal condition for sulfur dioxide to convert into sulfates. The chemicals are most effective in diminishing its visibility by scattering light before it can be observed, so water then acts as a catalyst promoting the reaction, causing the pollution to move so rapidly.

 "The main difference I noticed in the coastal air pollution versus continental air pollution is that the coast pollution was very acidic," Dr. Zhou said. "Acidic means it’s worse for your health compared to non-acidic particles."


Despite the gravity of noting this study, Dr. Zhou told UH she hopes the study will encourage other researchers in their own understanding of pollution in the Gulf Coast across the state and potentially come up with solutions to address these concerns. Not to mention open doors for other questions researchers can examine.  

"Almost the entire state of Texas is potentially under oceanic flow throughout the year," she concluded. "How far can this sulfur pollution come inland and how frequently can this happen?"