Air pollution monitoring refers to the process of determining the types and concentrations of pollutants in the atmosphere, observing their temporal and spatial distribution and changing rules. The purpose of air pollution monitoring is to identify the pollutants in the atmosphere, master their distribution and diffusion rules, and monitor the emission and control of atmospheric pollution sources.

Ø Nitrogen oxide monitoring

Nitrogen oxide monitor adopts chemiluminescence method to measure the luminous intensity of the gas-phase luminescence reaction between NO and O₃, and the luminous intensity is proportional to the concentration of nitric oxide, thus the concentration of nitric oxide is determined; the determination of nitric oxide, nitrogen dioxide, and nitrogen oxide in the sample gas can be realized by alternately passing through the reaction chamber of nitric oxide and total nitric oxide.

Ø Sulfur dioxide monitoring

The sulfur dioxide monitor adopts ultraviolet fluorescence method. The ultraviolet light emitted by zinc lamp is filtered into monochromatic light of 214nm and focused into SO₂ reaction chamber. SO₂ in sample gas absorbs ultraviolet light to generate energy level transition, SO₂ changes from ground state to excited state, SO₂ in excited state is unstable, and the fluorescence with central wavelength of 330nm is emitted instantaneously. The intensity of fluorescence is directly proportional to SO₂ concentration. The PMT converts optical signal into electrical signal, thus measuring SO₂ concentration.

BEIJING HAMAMATSU PHOTON TECHNIQUE INC. can provide PMTs and detectors for NOx and SO₂ detection.

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