Acousto-Optic Differential Optical Absorption Spectroscopy for Atmospheric Measurement of Nitrogen Dioxide in Hong Kong

2004 ◽  
Vol 58 (12) ◽  
pp. 1462-1468 ◽  
Author(s):  
Andrew Y. S. Cheng ◽  
M. H. Chan
Keyword(s):  
Hong Kong ◽  
Optical Absorption ◽  
Nitrogen Dioxide ◽  
Absorption Spectroscopy ◽  
Differential Optical Absorption Spectroscopy ◽  
Optical Absorption Spectroscopy ◽  
Atmospheric Measurement

scholarly journals Spatially resolved measurements of nitrogen dioxide in an urban environment using concurrent multi-axis differential optical absorption spectroscopy

2006 ◽  
Vol 6 (6) ◽  
pp. 12671-12700
Author(s):  
R. J. Leigh ◽  
G. K. Corlett ◽  
U. Frieß ◽  
P. S. Monks
Keyword(s):  
Remote Sensing ◽  
Optical Absorption ◽  
Nitrogen Dioxide ◽  
Urban Environment ◽  
Absorption Spectroscopy ◽  
Differential Optical Absorption Spectroscopy ◽  
Optical Absorption Spectroscopy ◽  
High Time Resolution ◽  
In Situ Techniques

Abstract. A novel system using the technique of concurrent multi-axis differential optical absorption spectroscopy system has been developed and applied to the measurement of nitrogen dioxide in an urban environment. Using five fixed telescopes, slant columns of nitrogen dioxide, ozone, water vapour, and the oxygen dimer, O4, are simultaneously retrieved in five vertically separated viewing directions. The application of this remote sensing technique in the urban environment is explored. Through, the application of several simplifying assumptions a tropospheric concentration of NO2 is derived and compared with an urban background in-situ chemiluminescence detector. The remote sensing and in-situ techniques show good agreement. Owing to the high time resolution of the measurements, the ability to image and quantify plumes within the urban environment is demonstrated. The CMAX-DOAS measurements provide a useful measure of overall NO2 concentrations on a city-wide scale.

scholarly journals Long term NO<sub>2</sub> measurements in Hong Kong using LED based Long Path Differential Optical Absorption Spectroscopy

2011 ◽  
Vol 4 (6) ◽  
pp. 6615-6642
Author(s):  
K. L. Chan ◽  
D. Pöhler ◽  
G. Kuhlmann ◽  
A. Hartl ◽  
U. Platt ◽  
...  
Keyword(s):  
Hong Kong ◽  
Optical Absorption ◽  
Absorption Spectroscopy ◽  
Differential Optical Absorption Spectroscopy ◽  
Optical Absorption Spectroscopy ◽  
Data Sets ◽  
Ozone Monitoring Instrument ◽  
Data Set ◽  
Weekly Cycle

Abstract. In this study we present the first long term measurements of atmospheric nitrogen dioxide (NO2) using a LED based Long Path Differential Optical Absorption Spectroscopy (LP-DOAS) instrument. This instrument is measuring continuously in Hong Kong since December 2009, first in a setup with a 550 m absorption path and then with a 3820 m path at about 30 m to 50 m above street level. The instrument is using a high power blue light LED with peak intensity at 450 nm coupled into the telescope using a Y-fibre bundle. The LP-DOAS instrument measures NO2 concentrations in the Kowloon Tong and Mong Kok district of Hong Kong and we compare the measurement results to concentrations reported by monitoring stations operated by the Hong Kong Environmental Protection Department in that area. Hourly averages of coinciding measurements are in reasonable agreement (R = 0.74). Furthermore, we used the long-term data set to validate the Ozone Monitoring Instrument (OMI) NO2 data product. Monthly averaged LP-DOAS and OMI measurements correlate well (R = 0.84) when comparing the data for the OMI overpass time. We analyzed weekly patterns in both data sets and found that the LP-DOAS detects a clear weekly cycle with a reduction on weekends during rush hour peaks, whereas OMI is not able to observe this weekly cycle due to its fix overpass time.

scholarly journals NO<sub>2</sub> measurements in Hong Kong using LED based long path differential optical absorption spectroscopy

2012 ◽  
Vol 5 (5) ◽  
pp. 901-912 ◽  
Author(s):  
K. L. Chan ◽  
D. Pöhler ◽  
G. Kuhlmann ◽  
A. Hartl ◽  
U. Platt ◽  
...  
Keyword(s):  
Hong Kong ◽  
Optical Absorption ◽  
Absorption Spectroscopy ◽  
Differential Optical Absorption Spectroscopy ◽  
Optical Absorption Spectroscopy ◽  
Ozone Monitoring Instrument ◽  
Data Set ◽  
Weekly Cycle ◽  
Mixing Ratios

Abstract. In this study we present the first long term measurements of atmospheric nitrogen dioxide (NO2) using a LED based Long Path Differential Optical Absorption Spectroscopy (LP-DOAS) instrument. This instrument is measuring continuously in Hong Kong since December 2009, first in a setup with a 550 m absorption path and then with a 3820 m path at about 30 m to 50 m above street level. The instrument is using a high power blue light LED with peak intensity at 450 nm coupled into the telescope using a Y-fibre bundle. The LP-DOAS instrument measures NO2 levels in the Kowloon Tong and Mongkok district of Hong Kong and we compare the measurement results to mixing ratios reported by monitoring stations operated by the Hong Kong Environmental Protection Department in that area. Hourly averages of coinciding measurements are in reasonable agreement (R = 0.74). Furthermore, we used the long-term data set to validate the Ozone Monitoring Instrument (OMI) NO2 data product. Monthly averaged LP-DOAS and OMI measurements correlate well (R = 0.84) when comparing the data for the OMI overpass time. We analyzed weekly patterns in both data sets and found that the LP-DOAS detects a clear weekly cycle with a reduction on weekends during rush hour peaks, whereas OMI is not able to observe this weekly cycle due to its fix overpass time (13:30–14:30 LT – local time).

scholarly journals Spatially resolved measurements of nitrogen dioxide in an urban environment using concurrent multi-axis differential optical absorption spectroscopy

2007 ◽  
Vol 7 (18) ◽  
pp. 4751-4762 ◽  
Author(s):  
R. J. Leigh ◽  
G. K. Corlett ◽  
U. Frieß ◽  
P. S. Monks
Keyword(s):  
Remote Sensing ◽  
Optical Absorption ◽  
Nitrogen Dioxide ◽  
Urban Environment ◽  
Absorption Spectroscopy ◽  
Differential Optical Absorption Spectroscopy ◽  
Optical Absorption Spectroscopy ◽  
High Time Resolution ◽  
In Situ Techniques

Abstract. A novel system using the technique of concurrent multi-axis differential optical absorption spectroscopy system has been developed and applied to the measurement of nitrogen dioxide in an urban environment. Using five fixed telescopes, slant columns of nitrogen dioxide, ozone, water vapour, and the oxygen dimer, O4, are simultaneously retrieved in five vertically separated viewing directions. The application of this remote sensing technique in the urban environment is explored. Through the application of several simplifying assumptions a tropospheric concentration of NO2 is derived and compared with an urban background in-situ chemiluminescence detector. Trends derived from remote sensing and in-situ techniques show agreement to within 15 to 40% depending on conditions. Owing to the high time resolution of the measurements, the ability to image and quantify plumes within the urban environment is demonstrated. The CMAX-DOAS measurements provide a useful measure of overall NO2 concentrations on a city-wide scale.

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