A device for measuring the number concentration of atmospheric ultrafine particles

Abstract

The invention discloses a number concentration measurement device of atmospheric ultrafine particles. The number concentration measurement device comprises an atmospheric airflow channel, a sample gas flow channel, a shell gas flow channel, a gas inlet device, a saturated solution device, a condensing device and an optical detection device. According to the number concentration measurement device, on the basis of a condensation nucleus theory and a light scattering measurement theory, i.e. shell gas flow passes through steam of a heated saturated solution and then is mixed with the air flow of the atmospheric ultrafine particles, the ultrafine particles pass through the condensing device and then are condensed to grow up, and then a light scattering technique is used for measuring the particles which are condensed to grow up, so as to obtain a number concentration value of the particles. By using the shell gas flow designed in the number concentration measurement device, the loss of sample gas flow particles can be reduced, and the condensation nucleus efficiency of the ultrafine particles can be effectively improved. The number concentration measurement device has the advantages of small and compact structure and high applicability, and the number concentration of the particles with a particle diameter range between 3 nm to 5 microns can be measured.

Description

technical field [0001] The invention relates to a device for measuring the number concentration of atmospheric ultrafine particles, which belongs to the technical field of atmospheric aerosol monitoring. Background technique [0002] Atmospheric particulate matter has a certain degree of harm to the environment and human health, and with the increase of number concentration and the decrease of particle size, the harm of atmospheric particulate matter to human health is greater. Epidemiological and toxicological studies have found that atmospheric ultrafine particles are significantly correlated with diseases and deaths of the human respiratory system and cardiovascular system. The researchers believe that the number concentration and chemical composition of atmospheric particulate matter are the main factors affecting human health, rather than the mass concentration as previously thought. Atmospheric ultrafine particles have a high number concentration and small particle si...

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Problems solved by technology

The minimum detection limit that can be obtained by the traditional stand-alone laser scattering instrument is 0.1 μm, and the maximum detection limit is 3 to 10 μm, which can no longer meet the detection requirements of ultrafine particles. The particle size range that the measuring device mentioned in the patent CN102890045A can measure is 10nm-10μm, the minimum detection limit can only reach 10nm, and it is impossible to measure particles with smaller particle sizes. It uses atmospheric particles to be directly mixed with saturated solution vapor, which will easily cause the diffusion loss of particles and affect the efficiency of condensation nuclei, thus affecting the measurement. result

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