Vosburgh Donna J H, Ku Bon Ki, Peters Thomas M
1. Department of Occupational and Environmental Safety and Health, University of Wisconsin-Whitewater, 800 West Main Street, Whitewater, WI 53190, USA.
Ann Occup Hyg. 2014 May;58(4):424-36. doi: 10.1093/annhyg/met082. Epub 2014 Jan 23.
The model DC2000CE diffusion charger from EcoChem Analytics (League City, TX, USA) has the potential to be of considerable use to measure airborne surface area concentrations of nanoparticles in the workplace. The detection efficiency of the DC2000CE to reference instruments was determined with monodispersed spherical particles from 54 to 565.7 nm. Surface area concentrations measured by a DC2000CE were then compared to measured and detection efficiency adjusted reference surface area concentrations for polydispersed aerosols (propylene torch exhaust, incense, diesel exhaust, and Arizona road dust) over a range of particle sizes that may be encountered in a workplace. The ratio of surface area concentrations measured by the DC2000CE to that measured with the reference instruments for unimodal and multimodal aerosols ranged from 0.02 to 0.52. The ratios for detection efficiency adjusted unimodal and multimodal surface area concentrations were closer to unity (0.93-1.19) for aerosols where the majority of the surface area was within the size range of particles used to create the correction. A detection efficiency that includes the entire size range of the DC2000CE is needed before a calibration correction for the DC2000CE can be created. For diesel exhaust, the DC2000CE retained a linear response compared to reference instruments up to 2500 mm(2) m(-3), which was greater than the maximum range stated by the manufacturer (1000 mm(2) m(-3)). Physical limitations with regard to DC2000CE orientation, movement, and vibration were identified. Vibrating the DC2000CE while measuring aerosol concentrations may cause an increase of ~35 mm(2) m(-3), whereas moving the DC2000CE may cause concentrations to be inflated by as much as 400 mm(2) m(-3). Depending on the concentration of the aerosol of interest being measured, moving or vibrating a DC2000CE while measuring the aerosol should be avoided.
美国德克萨斯州莱克城的EcoChem Analytics公司生产的DC2000CE型扩散充电器，在测量工作场所空气中纳米颗粒的表面积浓度方面具有很大的应用潜力。使用粒径范围为54至565.7纳米的单分散球形颗粒测定了DC2000CE相对于参考仪器的检测效率。然后，将DC2000CE测量的表面积浓度与在工作场所可能遇到的一系列粒径范围内多分散气溶胶（丙烯火炬废气、香、柴油废气和亚利桑那道路灰尘）的测量值及经过检测效率调整后的参考表面积浓度进行比较。DC2000CE测量的单峰和多峰气溶胶表面积浓度与参考仪器测量值的比值在0.02至0.52之间。对于大部分表面积在用于建立校正的颗粒粒径范围内的气溶胶，经过检测效率调整后的单峰和多峰表面积浓度的比值更接近1（0.93 - 1.19）。在能够创建DC2000CE的校准校正之前，需要一个涵盖DC2000CE整个粒径范围的检测效率。对于柴油废气，与参考仪器相比，DC2000CE在高达2500平方毫米每立方米的范围内保持线性响应，这超过了制造商规定的最大范围（1000平方毫米每立方米）。确定了DC2000CE在方向、移动和振动方面的物理限制。在测量气溶胶浓度时振动DC2000CE可能会导致浓度增加约35平方毫米每立方米，而移动DC2000CE可能会使浓度膨胀高达400平方毫米每立方米。根据所测量的目标气溶胶浓度，在测量气溶胶时应避免移动或振动DC2000CE。
