激光散射法与β射线法测量环境空气中颗粒物质量浓度的差异

The Difference of Particle Mass Concentration in Ambient Air Measured by Laser Scattering Method and β- rays Method

研究了激光散射法与β射线法测量环境空气中颗粒物质量浓度的差异。实验结果表明：激光散射法测得颗粒物PM10的质量浓度偏低,测得PM1.0的质量浓度偏高。对于PM2.5,当AQI≤100时,激光散射法的测定结果高于β射线法,AQI〉100时,激光散射法的测定结果低于β射线法。两种方法测得数据的相关性为PM2.5〉PM10〉PM1.0,相关系数分别为0.9462,0.8540,0.8508。假设β射线法测定颗粒物日均值浓度结果为真值,激光散射法测定颗粒物PM10的相对误差在-10%~10%之间出现的频率最高,为27.4%,测定PM2.5的相对误差在-10%~10%之间出现的频率最高,为47.9%,测定PM1.0的相对误差大部分大于20%,出现频率为64.4%。用t检测法确定两种检测方法之间的系统误差发现测定颗粒物PM2.5的日均值无显著差异,而测定颗粒物PM10和PM1.0的日均值存在显著性差异。

The difference of particle mass concentration in ambient air measured by laser scattering method and β- rays method is studied. It shows that measured concentration of PM10 is lower while PM1. 0concentration is higher using laser scattering method. As for PM2. 5,measured concentration is higher using laser scattering method when AQI≤100. But when AQI 〉 100,measured concentration is lower. It is founded that particle concentrations measured using the two different methods have a significant positive correlation. The correlation coefficients are 0. 9462, 0. 8540, 0. 8508 for PM2. 5, PM10 and PM1. 0respectively. Supposing that the concentration measured by β- rays method is true value, the relative error of PM10 concentration measured by laser scattering method is mainly- 10% ~ 10% and the appearing frequency in the interval is27. 4%. As for PM2. 5,the appearing frequency in the interval is 47. 9%. However,the relative error of PM1. 0is mainly larger than 20% and the appearing frequency is 64. 4%. t detection method is used to determine the system error between the two measuring methods. It shows that daily mean values of PM2. 5are almost the same while the difference is apparent for PM10 and PM1. 0.