Automated Measurement of Nitrogen Trifluoride in Ambient Air

Abstract

We present an analytical method for the in situ measurement of atmospheric nitrogen trifluoride (NF(3)), an anthropogenic gas with a 100-year global warming potential of over 16,000. This potent greenhouse gas has a rising atmospheric abundance due to its emission from a growing number of manufacturing processes and an expanding end-use market. Here we present a modified version of the "Medusa" preconcentration gas chromatography/mass spectrometry (GC/MS) system of Miller, B. R.; Weiss, R. F.; Salameh, P. K.; Tanhua, T.; Greally, B. R.; Mühle, J.; Simmonds, P. G. Anal. Chem.2008, 80 (5), 1536-1545. By altering the techniques of gas separation and chromatography after initial preconcentration, we are now able to make atmospheric measurements of NF(3) with relative precision <2% (1σ) for current background clean air samples. Importantly, this method augments the currently operational Medusa system, so that the quality of data for species already being measured is not compromised and NF(3) is measured from the same preconcentrated sample. We present the first in situ measurements of NF(3) from La Jolla, California made 11 times daily, illustrating how global deployment of this technique within the AGAGE (Advanced Global Atmospheric Gases Experiment) network could facilitate estimation of global and regional NF(3) emissions over the coming years.

Recent increases in the atmospheric growth rate and emissions of HFC-23 (CHF&lt;sub&gt;3&lt;/sub&gt;) and the link to HCFC-22 (CHClF&lt;sub&gt;2&lt;/sub&gt;) production

“…Ambient air measurements of HFC-23 and HCFC-22 at each site are made using the AGAGE GC-MS-Medusa instrument which employs an adsorbent-filled (HayeSep D) microtrap cooled to ∼ −175 • C to pre-concentrate the analytes during sample collection from 2 L of air (Miller et al, 2008;Arnold et al, 2012). Samples are analysed approximately every 2 h and are bracketed by measurements of quaternary standards to correct for short-term drifts in instrument response.…”

Global and regional emissions estimates of 1,1-difluoroethane (HFC-152a, CH&lt;sub&gt;3&lt;/sub&gt;CHF&lt;sub&gt;2&lt;/sub&gt;) from in situ and air archive observations

“…Based on a Peltier-cooled pre-concentration microtrap cooled to −50 • C during the adsorption phase, the ADS provided on-site calibrated air samples every 4 h, i.e., six per day (Simmonds et al, 1995). In 2004, the ADS-GC-MS was replaced with a more advanced custom-built pre-concentration system (Medusa) with enhanced cooling to ∼ −180 • C and the relatively mild adsorbent HayeSep D (Miller et al, 2008;Arnold et al, 2012). Agilent 5973 MSDs (mass selective detector) were also upgraded to the Agilent 5975 MSDs over the course of the Medusa observations.…”

Earth’s Climate System

“…As a consequence, movements are underway throughout the world to reduce both the direct emission of aerosols as well as the emission of aerosol precursors. Reductions in the abundance of tropospheric aerosols and aerosol precursors, in response to air quality legislation motivated by public health concerns, have been readily observed by space-borne 33 Atmospheric abundance of NF 3 peaked at 0.0012 ppb in late 2011 (Arnold et al 2012) and radiative efficiency is 0.2 W m −2 ppb −1 (Table 8. instrumentation throughout the world (Streets et al 2013;Yoon et al 2014;He et al 2016). As such, the climate system is presently transitioning from an era where the cooling of climate due to aerosols may have had close to comparable strength as GHG induced warming to an era where the radiative warming due to GHGs will dominate aerosol cooling (Smith and Bond 2014).…”