Laser induced fluorescence based detection of atmospheric nitrogen dioxide and comparison of different techniques during the PARADE 2011 field campaign

Abstract

Abstract. GANDALF (Gas Analyzer for Nitrogen Dioxide Applying Laser-induced Fluorescence), a new instrument for the detection of nitrogen dioxide based on the laser-induced fluorescence (LIF) technique, is presented in this paper. GANDALF is designed for ground based and air-borne deployment with a robust calibration system. In the current setup, it uses a multi-mode diode laser (447 -450 nm) and performs in situ, continuous, and autonomous measurements with a laser pulse repetition rate of 5 MHz. The performance of GANDALF was tested during the field experiment at a forested location with urban influence where 20 NO x levels were between 0.12 and 22 parts per billion by volume (ppb v ). Based on the field results, the limit of detection is estimated at 5 -10 parts per trillion by volume (ppt v ) in 60 s at a signal to noise ratio (SNR) of 2. The overall accuracy and precision of the instrument are better than 5 % (1 σ) and 0.5 % + 3 ppt v (1 σ min -1 ), respectively. A comparison of nitrogen dioxide measurements based on several techniques during the field campaign is presented to explore methodic differences. 25

Nitrogen oxides in the free troposphere: implications for tropospheric oxidants and the interpretation of satellite NO2 measurements

“…Accurate in situ measurements of NO 2 in the free troposphere are challenging because of low NO 2 concentrations and interferences from labile non-radical NO x reservoirs (HNO 4 , N 2 O 5 , and organic nitrates) when sampling at cold temperatures (Bradshaw et al, 1999;Browne et al, 2011;Reed et al, 2016;Nussbaumer et al, 2021). Current techniques to measure NO 2 in situ involve either (i) the conversion of NO 2 to NO by photolysis followed by measurement of NO through chemiluminescence (photolysischemiluminescence or P-CL; Walega et al, 1991;Ryerson et al, 2000;Bourgeois et al, 2022) or (ii) the direct measurement of NO 2 through laser-induced fluorescence (LIF; e.g., Thornton et al, 2000;Matsumoto et al, 2001;Javed et al, 2019), cavity ring-down spectroscopy (Osthoff et al, 2006), or cavity-enhanced differential optical absorption spectroscopy (Platt et al, 2009). Intercomparisons of NO 2 instruments have generally found agreement among the different techniques at high (> 1 ppbv -parts per billion by volume) NO 2 concentrations (Thornton et al, 2003;Fuchs et al, 2010;Sparks et al, 2019;Bourgeois et al, 2022) but poor agreement in free tropospheric conditions, where NO 2 concentrations are below 50 pptv (parts per trillion by volume) and close to the instrument detection limits (Gregory et al, 1990a;Sparks et al, 2019).…”

Comparison of Airborne Reactive Nitrogen Measurements During WINTER

“…A CRDS comparison with CL sampling ambient air (having NO 2 up to 60 ppbv) for 6 days in 2009 found NO 2 and NO agreed within 1% and 3%, respectively (Fuchs et al, ). In a recent paper, Javed et al () compared LIF, CL, CRDS, LP‐DOAS (long‐path differential optical absorption spectroscopy), and CE (cavity‐enhanced)‐DOAS NO 2 instruments at a forested site in Germany. They reported agreement within the experimental limitations and instrumental uncertainties over the ambient concentration range of 0.13 to 22 ppbv.…”