Air Pollutant Trends
Burning Fuels Causing a Warming Planet
We rely on the burning of fossil fuels (i.e., gasoline, coal, and natural gas) for nearly all aspects of our everyday lives.
This heightened energy demand for and use of these finite resources over the last century has introduced an excess of noxious gases to the atmosphere.
Some of these gases (e.g., carbon dioxide, methane, and nitrous oxide), also known as greenhouse gases, are responsible for trapping reflected heat from the earth’s surface.
This process is vital to maintaining a habitable planet, but excess greenhouse gases in the atmosphere enhances this effect by trapping more heat and increasing air temperatures globally.
Warmer air temperatures impact rain and snow patterns, sea level rise, and species migrations.
Acid Rain Impact on Kezar Lake Watershed
Fossil fuel combustion also emits sulfur dioxide and nitrogen oxides to the atmosphere. These gases react with water vapor, oxygen, and other gases in the atmosphere to form sulfuric and nitric acids, which fall on water and land surfaces as acid rain.
Acid rain lowers the pH of aquatic and terrestrial systems, causing reduced reproductive capacity of sensitive aquatic organisms, lower body weight of fish, decreased species diversity, and forest mortality.
Substantial effort was made to reduce acid rain deposition through the 1970 Clean Air Act, which established national ambient air quality standards for controlling these noxious emissions.
While emissions have decreased and the damaging short-term effects of acid rain have been minimized, many waterbodies are still recovering from the long-term effects of acidification.
In particular, parts of the northeastern United States have thin soils with granite geology that lack carbonates, a key component of a system’s buffering capacity or ability to neutralize acidic compounds.
We see this in streams of the Kezar Lake watershed where low-pH rain (5.0) temporarily decreases the pH of surface waters. These swings in pH create stressful environments for sensitive aquatic organisms.