Design and Operation of A portable Laser Absorption System to Detect NO2 gas Concentration

Abstract

In this study a portable laser absorption system was designed and operated to detect nitrogen dioxide gas (NO 2) concentration which is a common air pollutant, by means of measurements of laser beam intensity transmitted through this gas inside a glass tube using laser absorption spectroscopy. Diode laser of 650 nm wavelength and power of 10 mW with photodiode detector, was used to calculate the concentration of NO2 in samples collected from cars exhaust using petroleum products (benzene, gasoline, gas, and mixture of benzene and oil) as fuel, and from petroleum refinery station out of Khartoum at distances of 300m and 2000m apart. The study was illustrated that, the attenuation of laser intensity by NO2 and the concentration of it in the collected samples depends on the iii ‫‪sort of the fuel, the age of the engine, while for it depends on the distance‬‬ ‫‪between the sample collection area and the refinery‬‬ ‫‪The system succeeded to detect the existence of NO 2 in the collected‬‬ ‫‪samples. The system was able to determine the NO 2 concentration in all‬‬ ‫‪the samples with high efficiency in a simple way to get real and accurate‬‬ ‫‪results. The system was so cheep, fast and simple to be used as a portable‬‬ ‫.‪device in different areas of fuel combustion without need of fixed lab‬‬