Friday, January 18, 2013

Vehicle Emissions and Water Quality

Understanding Atmospheric Deposition in Tampa Bay(3 page pdf, Bay Region Atmospheric Chemistry Experiment (BRACE))

Also discussed here: From the Tailpipe to Tampa Bay: Air Pollution Research Reveals Impact of Cars(Bradenton Times, Dec. 17, 2012)

Vehicle emissions not only cause harmful health impacts for people near them but they also affect the quality of the water near urban areas by adding nitrogen dioxides to the water off the coast which promotes algae growth, starving the fish of oxygen. Today we review a report from Tampa on the amount of nitrogen oxides reaching the water from the atmosphere, mainly from vehicle emissions that pollute Tampa Bay. Many of the same strategies for improving urban air quality on land apply here as well for water quality: more low emission vehicles, more monitoring of dry deposition and reestablish atmospheric monitoring stations. As EPA notes: “driving a car is a typical citizen’s most polluting daily activity.” tampa mapno2 and tampa  

Key Quotes:

“Atmospheric nitrogen comes from emissions from both natural and anthropogenic (human-derived) sources. Natural sources include fecal matter from wild animals, forest fires, lightning, oceans, soils, and vegetation. In a densely populated watershed such as Tampa Bay’s, natural sources make up a relatively small component of all atmospheric deposition. Human-derived sources include emissions from fertilizer production and use, human and farm animal waste, and fossil fuel combustion.”

 “too much nitrogen can cause excessive algae growth that can block sunlight necessary for seagrass growth. It can also deplete dissolved oxygen levels, leading to fish kills.”

 “Direct Atmospheric Deposition occurs when air pollutants such as NOx and NH3 fall directly onto Tampa Bay, interacting with the bay’s water surface.....Indirect Atmospheric Deposition occurs when air emissions fall first onto the land or watershed surface and then enter the bay with stormwater.”

 “cars, trucks, and other mobile vehicles deposit four times more nitrogen oxide, or NOx, in Tampa Bay than power plants…mobile sources have a disproportionately large impact, because emissions from cars, trucks and boats are generated closer to the ground, and more of their emissions wind up in the bay”

 "In 2002….57% of all nitrogen entering Tampa Bay came from atmospheric sources. Of that, 17% was direct deposition to the bay; 40% returned indirectly to the bay via stormwater runoff from the watershed. In 2002, nitrogen coming from the air made up 1,973 tons of the 3,485 total tons of nitrogen entering the bay.”

  • "Encourage use of low-emission personal vehicles and public transportation. US EPA cites that driving a car is a typical citizen’s most polluting daily activity.
  • Support partner actions..related to air quality improvements.
  • Re-establish atmospheric deposition monitoring stations within the Tampa Bay watershed to track changes in emissions.
  • Develop better monitoring and measurements of direct dry deposition.”
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