Forums | ZGroup

02 June 2023, 10:43 AM

Overview

The Wideband Integrated Bioaerosol Sensor (DMT, WIBS-NEO) is a precision instrument for the measurement of biological aerosols such as moulds, pollen and fungi. The instrument is manufactured by Particle Measuring Technology (DMT) in the USA. It measures single particle light scattering, fluorescence (three different metrics), particle size, and asymmetry factor (AF) for aerosols from 0.5 to 15 µm and calculates the number concentration distribution of the aerosol. The instrument uses a UV-xenon light source to excite single-particle aerosols to produce fluorescence.

WIBS-NEO can be used for fixed point observations in laboratories, on the ground and in pylons, or mounted on aircraft and balloons for aerial observations, and is an effective tool for detecting environmental bioaerosols, monitoring air quality, and studying the effects of bioaerosols on human health.

The principle of operation

The principle of operation of the WIBS-NEO is shown in the diagram on the left. Sample aerosols are pumped into the inlet of the instrument by the built-in air pump, arranged in a single row as they pass through the laminar flow feed system, and subsequently scattered in all directions by a laser beam with a wavelength of 635 nm. The measured forward scattered light is used to determine the shape of the aerosol particles; the measured lateral scattered light is converted into a current pulse and triggers the first xenon tube (Xe1) at a wavelength of 280 nm, from which the induced fluorescence (emitted by the aerosol) is aggregated and filtered and sent to two fluorescence detectors, FL1 and FL2. The fluorescence induced by this source is also aggregated and filtered and sent to the two fluorescence detectors, FL1 and FL2.

The WIBS-NEO generates a two-dimensional (2x2) excitation-emission light matrix for each aerosol particle, corresponding to three fluorescence measurements for each particle (the Xe2/FL1 channel is ignored because the signal received by FL1 is saturated). xe1/F1 is highly sensitive to tryptophan, while f2 is essentially representative of NADH.

Technical specifications

• Measurement parameters: single particle light scattering; single particle fluorescence (three independent measurements); aerosol size; aerosol asymmetry factor
• Calculation parameters: Aerosol concentration particle size range: 0.5 - 15 μm;
• Maximum number concentration: approx. 2x104 particles/litre (this is the number concentration with all measured parameters, the total aerosol concentration is higher than this value);
• Fluorescence excitation: dual wavelengths, 280 nm and 370 nm;
• Fluorescence emission: dual wavelengths, 310 - 400 nm and 420 - 650 nm;
• Flow rate: total flow rate of 2.5 L/min, with a sample flow rate of 0.3 L/min and a sheath gas flow rate of 2.2 L/min;
• Laser: 635 nm diode laser;
• Power supply: 100 W, 90 - 230 VAC
• Dimensions/weight: 37 cm L x 45 cm W x 24.14 cm H (5 cm increase in instrument height with inlet port attached)/13.6 kg;

Standard Equipment

• 1 Bioaerosol double UV spectrometer
• 1 instrument control, real-time data acquisition and display software package
• 1 custom reusable instrument transport case

Main applications

Bioaerosol studies (moulds, pollen, fungi, etc.)

Ambient air quality studies

Aerosol health effects studies

Data acquisition software

The WIBS user visualisation graphical software is composed of the following parts. The graphical window (left) shows a time series of each parameter (fluorescence variation, particle size variation, particle concentration, etc.); the main window (top right) is used to control and monitor the instrument; the scatter plot (bottom right) shows the correlation of the optional parameters. There is also a frequency window displayed as a bar graph.

References

1. 1. D. Baumgardner, K. McCabe, G. Kok, G. Granger, and M. Hernandez. "Using Real-time Multibank time Fluorescence Signatures to Discriminate between Bioaerosol Classes": A presentation given October 3, 2013, at the AAAR Conference in Portland, Oregon.
2. E. Toprak and M. Schnaiter, "Fluorescent biological aerosol particles (FBAPs) measured with the Waveband Integrated Bioaerosol Sensor WIBS-4: laboratory tests combined with a one-year field study." Atmos. Chem Phys. Discuss., 12, 17607–17656, 2012.
3. C. Pohlker, J.A. Huffman, and U. Poschl, "Autofluorescence of atmospheric bioaerosols-fluorescent biomolecules and potential interferences," Atmos. Meas. Tech., 5. 37-71, 2012.
4. A.M. Gabey, M.W. Gallagher, et al. "Measurements and comparison of primary biological aerosol above and below a tropical forest canopy using a dual channel fluorescence spectrometer," Atmos. Chem. Phys., 10, 54453-4466, 2010.

------------------------------------------------------------------------------------------------------------------------

仪器简述

生物气溶胶双紫外光谱仪（英文名：Wideband Integrated Bioaerosol Sensor，品牌：DMT, 型号：WIBS-NEO）是一种测量霉菌、花粉、真菌等生物气溶胶的精密仪器。该仪器由美国粒子测量技术公司（DMT）制造。它能测量0.5 到15 微米气溶胶的单颗粒光散射、荧光（三种不同的指标）、粒径、以及不对称因子（AF），并且计算得到气溶胶的数浓度分布。该仪器使用紫外氙光源激发单颗粒气溶胶使之产生荧光。

WIBS-NEO既可用于实验室、地面和铁塔等定点观测，也可安装在飞机和气球上进行空中观测，是检测环境生物气溶胶、监测空气质量、以及研究生物气溶胶对人体健康影响的有效工具。

工作原理

WIBS-NEO的工作原理如左图所示。样本气溶胶被内置气泵抽入仪器的进样口，在经过层流进样系统时被排列成单行，随后通过波长为635nm 的激光束，向各个方向散射光。测到的前向散射光被用来确定气溶胶粒子的形状；测到的侧向散射光被转成电流脉冲，并触发第一个波长为280 nm 的氙气管（Xe1），由此诱发的（由气溶胶放射的）荧光经过聚集和滤光后被送到两个荧光探测器，FL1 和FL2。随后，第二个波长为370nm 的氙气管（Xe2）放光，由这个光源诱发的荧光同样通过聚集和滤光后同样被送至FL1 和FL2 那两个荧光探测器。

WIBS-NEO对每一颗气溶胶粒子都生成一个二维（2x2）的激发-发射光矩阵，相当于对每个粒子进行三次荧光测量（Xe2/FL1 通道因FL1 接收的信号已饱和而被忽略）。Xe1/F1 对色氨酸高度敏感，而F2 所测基本上代表NADH。

技术指标

• 测量参数: 单颗粒光散射量; 单颗粒荧光量（三种独立的测量值）; 气溶胶粒径; 气溶胶不对称因子
• 计算参数: 气溶胶浓度粒径范围: 0.5-15μm；
• 最大数浓度: 约2x104颗/升（这是含所有测量参数的数浓度，气溶胶总数浓度要高于此值）；
• 荧光激发: 双波长，280 nm 和370 nm；
• 荧光放射: 双波段，310-400 nm 和420 - 650 nm；
• 流量: 总流量2.5 L/min，其中样本流量0.3 L/min、鞘气流量2.2 L/min；
• 激光: 635nm 二极管激光；
• 电源: 100 W, 90 - 230 VAC
• 尺寸/重量: 37 cm 长 x 45 cm 宽 x 24.14 cm 高（连接进样口后仪器高度增加 5 cm）/13.6 kg；

标准配置

• 1 台生物气溶胶双紫外光谱仪
• 1 套仪器控制、实时数据采集和显示软件
• 1 个定制可重复使用的仪器运输箱

主要用途

• 生物气溶胶研究（霉菌、花粉、真菌等）
• 环境空气质量研究
• 气溶胶健康效应研究

数据采集软件

WIBS用户可视化图形软件由于以下几部分组成。图形窗口（左）显示各参数（荧光变化、粒径变化、粒子浓度等）的时间序列；主窗口（右上）用于控制和监控仪器；散点图（右下）显示可选参数的相关性。另有以柱形图显示的频率窗口。

参考文献

• D. Baumgardner, K. McCabe, G. Kok, G. Granger, and M. Hernandez. "Using Real-time Multibank time Fluorescence Signatures to Discriminate between Bioaerosol Classes": A presentation given October 3, 2013, at the AAAR Conference in Portland, Oregon.
• E. Toprak and M. Schnaiter, "Fluorescent biological aerosol particles (FBAPs) measured with the Waveband Integrated Bioaerosol Sensor WIBS-4: laboratory tests combined with a one-year field study." Atmos. Chem Phys. Discuss., 12, 17607–17656, 2012.
• C. Pohlker, J.A. Huffman, and U. Poschl, "Autofluorescence of atmospheric bioaerosols-fluorescent biomolecules and potential interferences," Atmos. Meas. Tech., 5. 37-71, 2012.
• A.M. Gabey, M.W. Gallagher, et al. "Measurements and comparison of primary biological aerosol above and below a tropical forest canopy using a dual channel fluorescence spectrometer," Atmos. Chem. Phys., 10, 54453-4466, 2010.