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 airborne deployment with a robust calibration system. In the current set-up, 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 summer of year 2011 (15 August–10 September) in a field experiment at Kleiner Feldberg, Germany. The location is within a forested region with an urban influence, where NOx levels were between 0.12 and 22 parts per billion by volume (ppb). Based on the field results, the limit of detection is estimated at 5–10 parts per trillion by volume (ppt) in 60 s at a signal-to-noise ratio (SNR) of 2. The overall accuracy and precision of the instrument are better than 5 % (1σ) and 0.5 %+3 ppt (1σ min−1), respectively. A comparison of nitrogen dioxide measurements based on several techniques during the field campaign PARADE 2011 is presented to explore methodic differences.

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, 2009). In a recent paper, Javed et al (2019) compared LIF, CL, CRDS, LP-DOAS (long-path differential optical absorption spectroscopy), and CE (cavityenhanced)-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.…”

Measurement of NO<sub><i>x</i></sub> and NO<sub><i>y</i></sub> with a thermal dissociation cavity ring-down spectrometer (TD-CRDS): instrument characterisation and first deployment

“…The chemistry leading to the formation of gas-phase NO x from NO y trace gases adsorbed at the denuder surface under humid conditions cannot be elucidated in detail with our experimental set-up. However, a strong humidity dependence in the heterogeneous generation of HONO and NO from NO 2 adsorbed on soot particles has been reported (Kalberer et al, 1999;Kleffmann et al, 1999). Formation of HONO from NO x has also been observed on wet aerosol and ground surfaces in field studies (Lammel and Perner, 1988;Notholt et al, 1992).…”

“…The best CLD devices have detection limits for NO and NO 2 in the single-digit parts per trillion by volume (pptv) range (Hosaynali Beygi et al, 2011;Reed et al, 2016;Tadic et al, 2020). Detection of NO 2 via LIF involves photoexcitation in its visible absorption band at wavelengths > 400 nm and detection of fluorescent emission at wavelengths > 600 nm, with detection limits of the order of parts per trillion by volume achieved for an integration time of a few seconds (Day et al, 2002;Javed et al, 2019). The structured spectrum of NO 2 between ≈ 400 and 600 nm is used to detect light absorption by ambient NO 2 by DOAS, using either broadband light sources (long-path DOAS, with a path length of more than a few kilometres) or natural sun-light (Platt et al, 1979;Leser et al, 2003;Pohler et al, 2010;Merten et al, 2011).…”

Measurement of NO<sub><i>x</i></sub> and NO<sub><i>y</i></sub> with a thermal dissociation cavity ring-down spectrometer (TD-CRDS): Instrument characterisation and first deployment

“…The best CLD devices have detection limits for NO and NO2 in single-digit pptv range (Beygi et al, 2011;Reed et al, 2016;Tadic et al, 2019). Detection of NO2 via LIF involves photo-excitation in its visible absorption band at wavelengths > 400 nm and detection of fluorescent emission at wavelengths > 600 nm, with detection limits of the order of pptv achieved for an integration time of a few seconds (Day et al, 2002;Javed et al, 2019). The structured spectrum of NO2 between  400 and 600 nm is used to detect light absorption by ambient NO2 by DOAS, using either broad-band light sources (long-path DOAS, over a few km pathlength) or natural sunlight (Platt et al, 1979;Leser et al, 2003;Pohler et al, 2010;Merten et al, 2011).…”