光散射法与β射线衰减-光散射联用法颗粒物在线测量方法对比

Inter-Comparison between Light Scattering and Beta-Attenuation-Light Scattering Particulate Matter On-Line Monitoring

为考察光散射法和β射线衰减-光散射联用法的适用性,以β射线衰减法颗粒物自动监测仪(BAM)为标准,于2016年2月4日—4月18日,在中国环境科学研究院利用β射线衰减-光散射联用法颗粒物自动监测仪(MP-CPM)与光散射法传感器对ρ(PM_(10))和ρ(PM_(2.5))测量结果进行了对比.结果表明:(1)MP-CPM与BAM测量ρ(PM_(10))的结果具有较好的一致性,相关系数为0.92,平均相对偏差为0.04%;ρ(PM_(2.5))结果一致性较差,相关系数为0.69,MP-CPM测量ρ(PM_(2.5))整体较高于BAM,平均相对偏差为45.8%.(2)光散射法传感器与BAM测量ρ(PM_(2.5))结果一致性较好,相关系数为0.85,平均相对偏差为11.24%,但ρ(PM_(10))远低于BAM,平均相对偏差为-44.64%.在特殊污染情景下,光散射法将因受到较大影响而严重错估颗粒物浓度.烟花燃放期间,MP-CPM和光散射法传感器严重低估颗粒物浓度,与BAM测量颗粒物浓度的平均相对偏差均低于-50%;沙尘污染过程中,MP-CPM严重高估ρ(PM_(2.5)),与BAM测量ρ(PM_(2.5))结果平均相对偏差为79.27%,光散射法传感器严重低估ρ(PM_(10)),与BAM测量ρ(PM_(10))结果平均相对偏差为-59.35%.研究显示,不同原理的仪器,在不同的使用场景下应该区别对待.

In order to investigate the performance methods of light scattering and beta-attenuation-light scattering,inter-comparison between light scattering and beta-attenuation-light scattering combined method of particulate matter on-line monitoring equipment for PM10 and PM2.5based on beta-attenuation method（BAM） was conducted from February 2016 to April 2016 at the Chinese Research Academy of Environmental Sciences. The results showed that PM10 concentrations measured by MP-CPM were greatly correlated with BAM,with the correlation coefficient of 0. 92 and average deviation 0. 04%,much better than the results of PM2.5,for which the correlation coefficient was 0. 69 and the average deviation was 45. 8%. PM2.5measured by light scattering sensor was closely correlated with BAM,with correlation coefficient 0. 85 and average deviation11. 24%,but PM10 was far lower than the BAM results,with average deviation-44. 64%. In some special pollution episodes,the result of light scattering misestimated the real value of ambient PM. During fireworks,MP-CPM and light scattering sensorunderestimated the particulate mass concentration,the relative deviation of both to BAM was less than 50%. During dust pollution,PM2.5measured by MP-CPM was overestimated,with average deviation between MP-CPM and BAM 79. 27%,while PM10 measured by light scattering sensor was underestimated,with average deviation between light scattering sensor and BAM-59. 35%. The research shows that different principles of instrument should be treated differently under the different usage scenarios. The study provides scientific reference for the methods of light scattering and beta-attenuation-light scattering.