LY-DOAS Ultra-low Concentration UV-DOAS Gas Measurement Optical Module (Standard Type)

Module Introduction

LYDOAS Ultra-low Concentration UV-DOAS Gas Measurement Optical Module, based on ultraviolet differential optical absorption spectroscopy (DOAS), can be used to measure gaseous pollutants simultaneously such as SO2, NOx gases, etc. It has many advantages including high accuracy, fast response , simultaneous measurement of multiple gases, powerful anti-interference performance, and low detection limit, etc. It can be widely applied to fields of stationary source  emission monitoring, mobile pollution source emission monitoring, industrial process gas analysis, the lab gas analysis etc.



When the UV-Vis light of continuous spectrum passes through the target gas- in the gas cell, light of specific wavelength will be absorbed by the Target gas. The absorption (absorbance) of light is proportional to the concentration of the target gas. An empirical relation curve between the laboratory calibrated absorbance and the concentration of the sample gas is established by spectral analysis and chemometrics methods, then the concentration of the target gas can be calculated in real time according to the absorbance of the sample gas.  

LYDOAS UV-DOAS gas measurement module adopts a new type of multi-reflection gas chamber designed by LaoYing. After multiple reflections by the concave reflector in the gas chamber, the incident light finally converges to the light outlet. Since the light beam is reflected by reflectors fixed at both ends of the gas chamber the chamber wall is not involved in the light reflection, thus avoiding signal drift, sensitivity loss, etc. caused by aging of the gas chamber with traditional inner wall and ensuring the optical path stability in long-term use. The multi-reflection technique can achieve both small size and long optical path at the same time, and the optical path can be customized according to application requirements.


  • Adopt the UV-DOAS to measure the concentrations of SO2, NO, NO2 and other gases in real time, with no interference from water vapor or dust;
  • Adopt our independently developed deep ultraviolet spectrometer to optimize the ultraviolet spectral response performance;
  • Long service life and short warm-up time by using a low power consumption pulse xenon lamp as the light source.
  • Low power consumption,long service life and short warm-up time by using a pulse xenon lamp as the light source.
  • Constant temperature control of the gas chamber enables stronger environmental adaptability and ensures the accuracy and stability of measurement results;
  • Measuring NO2 directly , with no need of a reformer;
  • The measuring range can be customized;
  • The mechanical structure and specifications according to customer application requirements.
  • Ambient air analysis

  • Analysis of waste gas from pollution sources

  • Analysis of emission from mobile pollution Sources

  • Industrial gas analysis

  • The lab gas analysis


Technical Indicators


Technical Indicators

Technical Parameters

Measured gas




Measuring range




Customizable according to user requirements

Indication error

≤±2% FS

Detection limit



≤1% FS

Zero drift

≤±2% FS /24h

Measuring range drift

≤±2% FS /24h


Zero - calibration and spancalibration

Response time

T90 < 30 s@1L/min

Operating temperature


Relative humidity


Output signal

Concentration/Original AD value

Communication interface


Power supply



<100W(During warm-up);<15W(Stable operation)





Note: The concentration in the table is the mass concentration under the standard state (temperature 273.15 K, pressure 101.325 kPa).


The above parameters are totally up to the requirements of the relevant national standards. If product upgrades, or image does not match with real machine, please refer to the real machine.


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