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February 6, 2001

What Is the Major Source of Air Pollution in Mobile County?

It Depends On Who You Ask,
And the Results May Surprise You

by Edmund Tsang

An environmental profile of coastal Alabama residents was recently constructed by researchers from the University of South Alabama based on a November, 1999 survey of 1,270 adults living in Mobile and Baldwin counties. One of the questions in the telephone survey asked respondents to identify the major source of air pollution in coastal Alabama. "Industries" was cited by 57.4 percent of those surveyed; 3.9 percent named "incinerators"; and 36.3 percent identified "automobiles" as the major source of air pollution in Mobile County. The remaining 2.4 percent represent respondents who indicated they do not know or gave no answer. Based on these results, the researchers stated that 62 percent of the respondents replied they know the major source of air pollution but failed to identify it, and only 36 percent of those who replied they know the answer were able to identify it. The researchers said they use the national norm -- automobiles as the major source of air pollution -- in evaluating the responses to the question on major source of air pollution in Mobile County.

Even though the national norm as well as the views of opinion makers point to automobiles as the main culprit of air pollution in Mobile County, data provided by the Alabama Department of Environmental Management (ADEM) and the Environmental Protection Agency (EPA) show that perhaps coastal Alabamians have it right all along regarding the major source of air pollution in Mobile County.

Bill Finch, the environmental editor of the Mobile daily newspaper, told The Harbinger in a telephone interview that the stories the paper has published focus on the seven pollutants mentioned in the Clean Air Act, which include nitrous oxide and ground-level ozone. "Getting a handle" on the TRI pollutants is "difficult," Mr. Finch said in a telephone interview. "We are in the same boat as other cities" regarding air quality, he concluded.

According to the Alabama Department of Environmental Management, regarding nitrous oxide emission in Mobile County in 1996, the latest year for which data are available, automobiles and off-road vehicles accounted for 23 percent (31.98 million pounds) while point sources due primarily to industries accounted for 73 percent (102.6 million pounds) of the total emitted. About one-half of all industrial emissions came from Alabama Power Company's Barry Steam Plant. Regarding volatile organic compounds (VOC), a main component of ground-level ozone, mobile sources such as automobiles accounted for 16 percent (25.2 million pounds); point sources such as industries accounted for 26 percent (42.28 million pound); and area sources -- those facilities, such as dry cleaners, that are small emitters of VOC compared to point sources -- accounted for 11 percent (18.39 tons). The remaining 47 percent of VOC are emitted as a result of biogenetic and other natural occurrences.

Compared to the total amounts of nitrous oxide and VOC emitted into the air of Mobile County, which are 140.9 million pounds and 85.9 million pounds, respectively, the 20 million pounds of TRI (Toxic Release Inventory) air pollutants in 1998 -- the latest year of which data are available -- is relatively small: about 8 percent of the total amount of hazardous air pollutants emitted in Mobile County.

Using nitrous oxide, VOC and TRI pollutants as the main air pollutants, automobiles and off-road vehicles are responsible for 31.98 million pounds of nitrous oxide and 25.2 million pounds of VOC emitted to the air of Mobile County in 1996. Point sources, which come mainly from industries and utilities, accounted for 102.6 million pounds of nitrous oxide, 42.28 million pounds of VOCs, and 20.28 million pounds of TRI pollutants emitted in Mobile County.

Casi Callaway, executive director of Mobile Bay Watch, Inc., said she disagrees with the view that automobiles are the main source of air pollution in Mobile County. "I still firmly believe that point sources are the number-one cause of ozone in Mobile rather than automobiles," Callaway said. "The number of automobiles versus the tons of emissions discharge of ozone precursor emission in 1997, according to my calculations, show that point sources were more numerous. Bill Finch (of Mobile Register) has broken the math down to one sport utility vehicle (SUV) emitting 40 pounds of nitrous oxide per year. The new IPSCO steel mill would emit 2,800 tons of nitrous oxide, and that would be equivalent to 140,000 SUVs according to Finch's estimates."

"How do they [the researchers] know that in Mobile, a county with an inordinate number of air pollution permits compared to citizens, pollution is caused by cars?" Callaway asked. Callaway also said the Mobile County Air Quality Study, which will be completed within a year, will have monitors that will be able to differentiate carbon monoxide emitted by cars from point source emissions.

Comparison Between Automobiles’ vs. Industry’s Contribution to Air Pollution in Mobile County Based on Nitrous Oxide, Volatile Organic Compounds (VOCs), and Toxic Release Inventory (TRI) Air Pollutants Emission


(Automobiles, etc.)

(factories & utilities)

Nitrous Oxide Nox

31.98 million pounds

102.60 million pounds


25.20 million pounds

42.28 million pounds

TRI Air Pollutants


20.28 million pounds


57.18 million pounds

165.16 million pounds

Source: Alabama Department of Environmental Management and Environmental Protection Agency.


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