Particulate mass concentration detection device and method for suspended particulate matter in the atmosphere

Abstract

The invention discloses a particulate matter mass concentration detection device applied to atmosphere suspended particulate matters, and a method thereof. The particulate matter mass concentration detection device is composed of a particulate matter sampling unit, a particulate matter measuring sensor, and a signal processing unit; the particulate matter sampling unit comprises air pumps, a particulate cutting head, a high-efficiency gas filter, a gas flowmeter, gas conduits, and a sampling power supply; the particulate matter measuring sensor comprises a multichannel particulate measuring part, a high-stability laser, an optically trap, a sheath gas unit, a metal capillary, optical lenses, and high-performance photoelectric detectors; and the signal processing unit comprises a signal conditioning circuit, a data acquisition card, a computer, and a signal power source. The particulate matter mass concentration detection device is reasonable in design; manufacturing and installation are convenient; and measuring optical path pollution caused by particulate matters is not caused. The signal processing unit is simple in structure, and excellent in performance; and data processing and reading are both convenient to realize. The measured particulate matter mass concentration dynamic performance is excellent; precision is high; and linearity is high.

Description

technical field [0001] The invention relates to the field of research and detection of particle mass concentration, in particular to a particle mass concentration detection device and method for suspended particles in the atmosphere. Background technique [0002] The mass concentration detection of particulate matter is becoming more and more important along with the increasingly severe air pollution in China. Existing methods for measuring the mass concentration of micron-scale suspended particulate matter in the atmosphere mainly include four kinds, 1) manual weighing method, the particles are collected on the filter membrane by a large flow sampler, and the filter membrane is weighed with a precision balance every few hours. The mass concentration of particulate matter can be obtained by weight. This method takes a long time to sample, the accuracy is greatly affected by environmental factors, and the real-time mass concentration cannot be obtained; 2) β-ray method, which...

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Problems solved by technology

Existing methods for measuring the mass concentration of micron-scale suspended particulate matter in the atmosphere mainly include four kinds, 1) manual weighing method, the particles are collected on the filter membrane by a large flow sampler, and the filter membrane is weighed with a precision balance every few hours. The mass concentration of particulate matter can be obtained by weight. This method takes a long time to sample, the accuracy is greatly affected by environmental factors, and the real-time mass concentration cannot be obtained; 2) β-ray method, which also collects particles on the filter membrane, and then passes through the ray from the radioactive source. Permeable membrane, judge the weight of particles according to the degree of attenuation of rays. This method uses a source of radiation, which is complicated and expensive to maintain. It does not use large-scale applications, and it is also impossible to obtain the real-time mass concentration of particles; 3) Conical element oscillating microbalance method , the particles are collected on the filter membrane, the square of the oscillation frequency of the cone element is inversely proportional to the mass of the particles on the filter membrane, so the mass concentration of the particles can be obtained according to the oscillation frequency of the cone element; the calibration of this method is very complicated and affected by temperature and humidity Larger, expensive and complicated maintenance work; 4) The light scattering method, which calculates the particle mass concentration according to the scattered light intensity when the particles pass through the optical path, is currently the only in-situ method for measuring the particle mass concentration, and it is also the most real-time method. It is a good method for measuring the mass concentration of particulate matter, but it is inconvenient to calibrate when using it, and needs to be recalibrated for different application environments; at the same time, according to the Mie theory, the distribution of light intensity scattered by submicron particles in all directions is relatively uniform, but with the particle size The scattered light is gradually concentrated forward, while the existing light scattering instrument is usually single-channel and the sensor is arranged in a 90° direction. Although it can help the research and improve the dynamic detection range of the instrument, it will cause large particles to scatter light. Underestimated, it will also lead to the inability to effectively detect submicron particles

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