Increasing atmospheric helium due to fossil fuel exploitation

Importance and Impact of International Agreements or Protocols to Protect Ozone and Beyond

“…Nevertheless, the O( 3 P) production rates from photolysis of NO2 below ~40 km altitude of stratosphere is more than the total O( 3 P) loss rates The similar situation with different time scale and impact would also appear for the enhancement of upper stratospheric H2SO4 concentration because of large SO2 injection in the stratosphere (41). This is also the case for the significant enhancement of other stratospheric gas molecules including noble gas molecules (49) Most of the CFC, HCFC and HFC molecules degrade predominantly by photolysis within middle stratosphere to produce halogen atoms and atmospheric lifetimes of CFC, HCFC and HFC molecules to produce halogen atoms are much longer than that of ozone photolysis (3,31,48). In the stratosphere where big ozone hole is observed, it has been pointed out above that how inert CO2 molecule via its regeneration in presence of steady state O( 1 D) assists the ClO + O( 3 P) → Cl + O2 reaction to cause ozone depletion via Cl + O3 → ClO + O2 reaction.…”

Short-term variability of atmospheric helium revealed through a cryo-enrichment method

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Tropospheric helium variations are tightly linked to CO2 due to the co-emission of He and CO2 from natural gas burning. Recently Birner et al (2022) showed that the global consumption of natural gas has measurably increased the He content of the atmosphere. Like CO2, He is also predicted to exhibit complex spatial and temporal variability on shorter time scales, but measurements of these short-term variations are lacking.

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“…Here we present the development of an improved gas delivery and purification system for the semi-continuous mass spectrometric measurement of the atmospheric He-to-nitrogen ratio (He/N2). The method replaces the chemical getter used previously by Birner et al (2021Birner et al ( , 2022 to preconcentrate He in an air stream with a cryogenic trap which can be more simply regenerated by heating and which improves the precision of the measurement to 22 per meg in 10 minutes (1σ). Using this "cryo-enrichment" method, we measured the He/N2 ratios in ambient air at La Jolla (California, USA) over 5 weeks in 2022.…”

“…Relying on archived air samples, Birner et al (2022) used this "getter-helium" method to show that the atmospheric concentration of 4 He increased by 1930±140 per meg since 1974. The atmospheric build-up has accelerated over time, paralleling natural gas usage, yielding a rate of rise in 2020 of ~66 per meg per year, based on the published curve fit.…”

“…Here we present an alternative He/N2 method that uses a different pressure-stabilization/switching system and substitutes a cryogenic trap for the titanium sponge getter. This "cryo-enrichment" method avoids the flow corrections of Birner et al (2021Birner et al ( , 2022, improves precision, and allows automated and nearly continuous measurements, because the cryo-trap can be regenerated by a brief 25-minute warming cycle. We illustrate the method by detecting quasi-continuous variations over several weeks in air drawn from the pier Scripps Institution of Oceanography ("Scripps Pier") in La Jolla, California, USA.…”