打印店内PM2.5和PM1的特征与影响因素分析

Analysis of characteristics and influencing factors of fine particulate matters and submicron particulate matters in printing shop

目的分析打印店内PM2.5和PM1的释放情况和特征,探讨打印机工作过程中颗粒物释放峰值的影响因素。方法于2018年1月5日在北京某打印店进行连续12hPM2.5和PM1的动态浓度监测,并采集PM2.5进行形态和元素构成分析;同时在密闭工作场所展开实验,分别探究不同打印机品牌、页面覆盖率及静息时间下打印机释放PM1的数量浓度峰值的差异。结果动态浓度监测显示,打印店工作时PM1的数量浓度和PM2.5的质量浓度峰值为7.510×10^4个/cm3和96.85μg/m^3;形态和成分分析显示,打印店室内PM2.5有球状(88.6%)、杆状(3.4%)和不规则状(8.0%),其粒径主要集中于100nm以下,并存在典型的团聚现象,分形维数D为2.591,PM2.5的主要构成元素为C、O、Si、Ca。3台不同品牌打印机打印工作中PM1释放峰值分别为3.60×10^4、3.43×10^4和0.31×10^4个/cm^3,差异没有统计学意义(χ^2=5.42,P>0.05)。当页面覆盖率依次为0%、2.5%、5%、10%、20%和50%时,A打印机工作中的PM1释放峰值依次为6.74×10^4、4.62×10^4、3.82×10^4、2.82×10^4、1.00×10^4和1.08×10^4个/cm^3,差异没有统计学意义(χ^2=7.01,P>0.05)。打印工作中PM1的释放峰值的自然对数值与打印前的静息时间及打印机部件加热锟的温度变化值均有关(r值分别为0.83和0.89,P值均<0.05)。结论打印店室内空气中PM2.5和PM1含量较高,形态和元素构成较为多样;加热锟的温度变化是导致PM1数量浓度峰值上升的重要因素之一。

Objective To analyze the physical characteristics of fine particulate matters (PM2.5) and submicron particulate matters (PM1), and investigate the factors influencing the emission peak of printer particles.Methods A 12-hour particle concentration monitoring for PM2.5 and PM1 was conducted in a printing shop on January 5th, 2018. PM2.5 in the air was analyzed after the monitoring process to figure out morphological characteristics and element composition of printer particles. Besides, experiments were carried out in an enclosed space to detect the number concentration peaks of PM1 during every printing process. Influencing factors investigated in this study were printer types, toner coverages and interval time between different printing processes.Results The 12-hour particles concentration monitoring showed that the number concentration of PM1 and the mass concentration of PM2.5 were 7.510×10^4 pt/cm^3 and 96.85 μg/m3. The diameter of most PM2.5 was less than 100 nm, with a fractal dimension of 2.591. Most PM2.5 appeared as regular spheres with typical agglomeration phenomenon, while some were in rhabditiform or irregular shapes. Element analysis showed that PM2.5 was mainly composed of C, O, Si, Ca, with less metallic element. The PM1 emission peak values of three printers were 3.60×10^4, 3.43×10^4, 0.31×10^4 pt/cm^3, respectively and the difference was not statistically significant (χ^2=5.42, P>0.05). When the page coverage rate was 0%, 2.5%, 5%, 10%, 20% and 50%, the PM1 emission peak value of printer A was 6.74×10^4, 4.62×10^4, 3.82×10^4, 2.82×10^4, 1.00×10^4 and 1.08×10^4 pt/cm^3, and the difference was also not statistically significant (χ^2=7.01, P>0.05). The natural logarithm of PM1 emission peak value in printing work was associated with the resting time before printing and the change value of heating roller temperature (r value was 0.83 and 0.89, respectively, all P values<0.05).Conclusion PM2.5 and PM1 in the printing shop stayed at a high level. Particles appeared as various shapes and element compositions were complex. The temperature change of heating roller was one of most important factors that lead to the increased number concentration peak of PM1.