|
PM2.5 is the chief air pollutants in most Chinese City. The PM2.5 parameter was usually evaluated by the weight per
unit volume (mg/m3) and the size was generally ignored. A method measuring the particle size distribution of PM2.5
based on light scattering was put forward. A special sector sensor, SSPA(Self Scanning Photodiode Array), was designed
to detect the distribution of weak space light energy. We researched a special optoelectronic detector with sector
detection area. The sensor has high sensitivity and high reliability. It's suitable for detecting the distribution of space
light energy, especially the diffraction and scattering energy distribution. The paper researched the signal processing
method. Based on the principle and characteristics of SSPA, a signal acquisition and processing method controlled by
computer was introduced. The amplification of weak signal, the matching of time sequence, the fast peak holding with
low leakage, the high speed A/D conversion and nonlinear correction were discussed. The method can acquire the peak
signal of every ring of sector SSPA with high accuracy and in real time. The particle size distribution of PM2.5 acquired
in Hangzhou City was analyzed. Results showed that the particles with diameter below 2.5um were above 90%.
|
