A Study On The Detection Method Of Aerosol Extinction Coefficient And Its Device Design

With the rapid economic development, air pollution problem has been paid more and more attention by people. Aerosol pollution would not only harm people's health but also the environment and climate have been greatly affected, such as the attenuation of light and the reduction of atmospheric visibility. Atmospheric aerosol extinction coefficient reflects its extinction characteristics, which can be used for further discussing of other environment quality problems, such as through rate and visibility atmospheric. So, it has great practical significance for the measurement of atmospheric aerosol extinction coefficient.The measurement system used an aerosol particle to filter membrane. In this measurement system, one beam was changed into two beams when it through the semi-permeable semi-reflective mirror. One beam went through the filtered atmosphere for reference; another beam was the one for measurement, which directly through the unfiltered air. Compared by these two lights, we got a good solution to reduce the interferences on the measurement results which caused by light instability and air molecules, thereby improving the accuracy of the system.The hardware part of this system included light modulation circuit, optical detection circuit, filter circuit and the true value conversion circuit etc. In Software part we adopted the modular design method. It includes the clock setting routines, LCD initialization routine, AD collection initialization routine, and pulse signal module. They took advantage of the rich resources of MSP430's own, then collected and operated the conditioned light, and finally operate the results to the user by the LCD display.In the test part, aerosols of different concentrations were tested. The result showed that this method had good linearity and error was less than 4%. The atmospheric aerosol detector developed by this method has many merits, such as small size, easy and quick to operate. So it has certain application value on monitoring air pollution and visibility.