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基于侧向散射激光雷达方程和Mie散射理论,建立了PM2.5浓度与侧向散射光强的关系模型,提出了一种基于电荷耦合器件(CCD)实时监测近地面PM2.5浓度的方法。设计了以波长532nm激光器为光源、CCD为接收器的侧向散射激光雷达装置,利用该装置测量了散射角在15°~45°之间的侧向散射回波信号图,从回波信号图提取灰度值矩阵并分析其光强分布。与赛默飞世尔科技公司PM2.5监测仪(SHARP)提供的测量结果对比,拟合了PM2.5浓度与3个灰度等级光总能量的关系式,拟合度均在0.97以上。该装置具有操作便利、移动便捷、监测实时、成本较低的特点,在近地面比后向散射激光雷达具有更高的精度与实用性,有助于建立PM2.5污染物的分布和运动模型并绘制污染地图。
Based on the theory of side scatter lidar and Mie scattering theory, a model of the relationship between PM2.5 concentration and lateral scattered light intensity was established. A method based on charge coupled device (CCD) to monitor the near-surface PM2.5 concentration in real time was proposed. The side scatter laser radar with 532nm laser as the light source and the CCD as the receiver was designed. Lateral scattered echo signal with scattering angle between 15 ° and 45 ° was measured. From the echo signal The gray value matrix is extracted and the light intensity distribution is analyzed. Compared with the measurement results provided by the Thermo Fisher Scientific PM2.5 Monitor (SHARP), the relationship between the PM2.5 concentration and the total energy of the three grayscale levels was fitted and the fitting degrees were all above 0.97. The device has the advantages of convenient operation, convenient movement, real-time monitoring and low cost. It has higher accuracy and practicability than near-surface backscatter lidar, and helps to establish the distribution and movement model of PM2.5 pollutant And draw a pollution map.