Saint Regis Mohawk Tribe
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SO2 - NO2

Sulfur dioxide (SO2) results from the combustion of sulfur-containing coal and oil used for energy production and industrial processes, largely from stationary sources such as power plants, steel mills, refineries, pulp and paper mills and from nonferrous smelters. Many emissions originate from tall stacks, enabling them to be dispersed according to wind patterns, temperature and velocity. Once released, Sulfur dioxide and other oxides of sulphur can combine with oxygen to form sulfates and with water to form aerosols of sulfurous and sulfuric acid. This mixture is a precursor of acid rain, which is associated with the acidification of lakes and streams, impacts on forest soils and the decline of certain high elevation tree

Nitrogen oxides (NOx) are a group of highly reactive gases primarily formed through the use of fossil fuels. Although short-term health effects of nitrogen dioxide are inconclusive, prolonged exposure may increase the incidence of respiratory conditions, especially in children. Nitrogen oxides are an important precursor to the formation of ground-level ozone and acid rain. Nitrogen deposition influences both chronic and episodic acidification of lakes and streams, sometimes resulting in uninhabitable conditions for fish and plankton species. Acidic deposition may also result in forest damage due to nutrient leaching, corrosion of historical structures and exacerbation of respiratory illnesses.

The Air Program is using a UV fluorescent analyzer for SO2 and a chemiluminescence analyzer for NOx. The SO2 analyzer depends on the radiation produced by SO2 molecules when excited by UV Radiation. A reference detector measures the excitation UV radiation and a photomultiplier tube measures the fluorescent radiation. The final concentration of SO2 is corrected for temperature and pressure changes, and is displayed in units of parts per million or milligrams per cubic meter.

The NOx analyzer is designed to measure the concentration of nitric oxide (NO), total oxides of nitrogen (NOx) and, by calculation, nitrogen dioxide (NO2). The instrument measures the light intensity of the chemiluminescent gas phase reaction of nitric oxide NO and ozone O3. The reaction of NO with ozone results in electronically excited NO2 molecules. The excited NO2 molecules release their excess energy by emitting a photon and dropping to a lower energy level. The analyzer samples the gas stream and measures the NO concentration by digitizing the signal from the analyzer's photomultiplier tube (PMT). A valve then routes the sample stream through a converter containing heated molybdenum to reduce any NO2 present to NO. The analyzer now measures the total NOx concentration. The NOx and NO values are subtracted from each other by the built in computer yielding the NO2 concentration. The three results NO, NO2, NOx are then further processed and stored by the computer yielding several instantaneous and long term averages of all three components.

General Motors - Styrene emissions associated with the General Motors Central Foundry-Powertrain plant in Massena, NY have impacted the St. Regis Mohawk Reservation for several years. Shutdown in 2009 and demolished in 2011. For more information go to the GM remediation update:

Alcoa-Modernization has started in 2013 with the Alcoa east plant for more information go to: In Onerahtokha/April 2013 Alcoa west was issued a record of decision for the Grasse River. For more information go to:

Saint Regis Mohawk Tribe Environment Division Posted: 2014.02.26