11:32 am - Monday May 28, 2012

Gaseous Pollution

Gaseous pollution is a harmful gas emitted into the air. This can include but not limited to: NOx’s, Sulphoxides, Methane, Carbon di/monoxide, PM10′s, PM2.5′s.

smokeThe most common method for controlling gaseous pollutants is the addition of add-on control devices to recover or destroy a pollutant. There are four commonly used control technologies for gaseous pollutants: absorption, adsorption, condensation, and incineration (combustion). The choice of control technology depends on the pollutant(s) that must be removed, the removal efficiency required, pollutant gas stream characteristics, and specific characteristics of the site. Absorption, adsorption, and condensation all are recovery techniques while incineration involves the destruction of the pollutant.

Gaseous pollutant monitoring can be accomplished using various measurement principles. As an example, sulfur dioxide monitoring can be accomplished with dynamic samplers for average concentrations over a 24-hour period and with static samplers for longer periods, e.g., 30 days. Some of the most common techniques to analyze gaseous pollutants include spectrophotometry, chemiluminescence, gas chromatography-flame ionization detector (GC-FID), gas chromatography-mass spectrometry (GC-MS), and Fourier transform infrared spectroscopy (FTIR).

With all sampling and analysis procedures, the end result is quantitative data. The validity of the data depends on the accuracy and precision of the methods used in generating the data. Accuracy is the extent to which measurements represent their corresponding actual values, and precision is a measurement of the variability observed upon duplicate collection or repeated analysis. To ensure the validity of data, various quality control measures are employed for each reference method. The primary quality control measure is calibration. Calibration checks the accuracy of a measurement by establishing the relationship between the output of a measurement process and a known input. Each of the reference methods has precise calibration procedures that must be followed to ensure accurate results.

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