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

摘要

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(PM10)和ρ(PM2.5)测量结果进行了对比.结果表明:①MP-CPM与BAM测量ρ(PM10)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(PM2.5)结果一致性较差,相关系数为0.69,MP-CPM测量ρ(PM25)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(PM2.5)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(PM10)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(PM2.5),与BAM测量ρ(PM2.5)结果平均相对偏差为79.27％,光散射法传感器严重低估ρ(PM10),与BAM测量ρ(PM10)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 PM2.5 based 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％.PM2.5 measured by light scattering sensor was closely correlated with BAM,with correlation coefficient 0.85 and average deviation 11.24％,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 sensor underestimated the particulate mass concentration,the relative deviation of both to BAM was less than 50％.During dust pollution,PM2.5 measured 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.