NO 2 measurements in Hong Kong using LED based long path differential optical absorption spectroscopy

Citations of this article
Mendeley users who have this article in their library.


<p><strong>Abstract.</strong> In this study we present the first long term measurements of atmospheric nitrogen dioxide (NO<sub>2</sub>) 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 NO<sub>2</sub> 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 (<i>R</i> = 0.74). Furthermore, we used the long-term data set to validate the Ozone Monitoring Instrument (OMI) NO<sub>2</sub> data product. Monthly averaged LP-DOAS and OMI measurements correlate well (<i>R</i> = 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).</p>




Chan, K. L., Pöhler, D., Kuhlmann, G., Hartl, A., Platt, U., & Wenig, M. O. (2012). NO 2 measurements in Hong Kong using LED based long path differential optical absorption spectroscopy. Atmospheric Measurement Techniques, 5(5), 901–912.

Register to see more suggestions

Mendeley helps you to discover research relevant for your work.

Already have an account?

Save time finding and organizing research with Mendeley

Sign up for free