Air that has only been over the Atlantic Ocean for more than two weeks can help to tell us the background concentrations of greenhouse gases in air arriving in Europe, and therefore offer important information for research, regulation and monitoring.

In NuClim, we will use the radon concentration in the air measured at Graciosa and @maceheadccaps.bsky.social to characterise how much the air reaching the stations has been recently influenced by land, or whether it has spent a long time just over the ocean.

Since most sources of pollution are also on land, just measuring the radon in air at remote sites in the ocean can tell us how likely it is that the air contains other pollution. Or how long the air has been away from any large pollution sources and is behaving like “background” air.

Together, these two properties mean that by just measuring radon, we can get some very interesting information about the air: mainly, in the past few weeks, how long has this particular bit of air spent over land.

As a gas, radon mixes with the air and is moved by wind. It has a half-life of about 3.8 days, so after 3.8 days half of the radon that came out of the ground will have disappeared. After 2 or 3 weeks, there is almost none left at all!

Radon is a naturally occurring radioactive gas. It originates nearly completely from land because it is created by the decay of naturally occurring radium in rocks and soils. As there is very little radium in suspended ocean sediments, not much radon comes from the oceans.

How does radon tell us about how air moves and mixes?
And what is the goal of our project?

Next round of lectures for the 7th @eumetsat.int @esa.int @ecmwf.int @copernicusecmwf.bsky.social Joint Training on Atmospheric Composition are tomorrow (9 Oct, CEST):

10:00 Alex Hoffman on EarthCARE observations
14:00 Viktoria Sofieva on stratospheric aerosols

eumetsat.zoom.us/meeting/regi...

Don’t miss this week’s online lectures at the 7th Joint Training Course on Atmospheric Composition hosted by @ecmwf.int, CAMS, @eumetsat.int and @esa.int (9–10 Oct 2025). Lectures are open to all and cover instruments & data, aerosol modelling & monitoring, ML applications and more.

At Graciosa, the daily commute on foot to the ARM station always included extra time to pat the goats and donkey.

Photos: Scott Chambers

Hello from the ICOS Atmosphere station Mace Head in Ireland! 👋 Our crew visited this unique coastal site, where some of the cleanest Atlantic air is measured, to film for the #ExploreICOS series. Stay tuned!

Learn more about the station: icos-cp.eu/news-and-eve...

Learn more on our website: www.nuclim.eu

The first measurements are running and more will follow soon!
NuClim aims to determine the baseline of greenhouse gas concentrations in the North Atlantic. We look at radon, greenhouse gases and a range of other parameters at the ENA observatory (Azores) and @maceheadccaps.bsky.social (Ireland).

@inesctec.bsky.social is using the world’s most sensitive detector, the 1500 L ANSTO radon monitor, with a detection limit as low as 0.025 Bq·m⁻³, to collect high-precision radon observations, pushing the boundaries of atmospheric research and extending applications of nuclear measurements.

Had fun setting up the Cluster Ion Counter on top of a shipping container at the ENA ARM site as part of the NuClim campaign. Proud to see it operational and measuring concentration + mobility of positive & negative cluster ions in real time! @inesctec.bsky.social @nuclim.bsky.social

Ready to start working on the installation of the radon detector and cluster ion counter at the ENA ARM facility in the Graciosa Island.

Terveisiä Azoreilta! Graciosan saarella mitataan nyt radonia ja kasvihuonekaasuja osana NuClim-hanketta. Mittaukset tukevat ilmastotutkimusta ja parantavat kasvihuonekaasupäästöjen arviointia.

‪@nuclim.bsky.social‬

www.ilmatieteenlaitos.fi/uutinen/4Tdl...

The container from the @ilmatieteenlaitos.fi , housing @icos-ri.eu -compliant instrumentation for carbon dioxide and methane gas measurements, has finally arrived at the Eastern North Atlantic (ENA) ARM User Facility on Graciosa Island in the Azores.

Do you want to know more about Project NuClim? then don't miss on Wednesday April 30th the poster X5.67 at the European Geosciences Union (EGU) meeting #EGU25

The container from the Finnish Meteorological Institute 🇫🇮 started its journey to the Azores 🇵🇹 ! Fully-prepared for high quality measurements of atmospheric carbon dioxide and methane, as well as comprehensive environmental radioactivity measurements. Can't wait for its arrival! 😀

We are eagerly awaiting for the arrival of the best atmospheric Rn-222 monitoring detector in the world! The very first CE Certified ANSTO 1500 L two-filter dual flow-loop radon monitor, that has left Australia and is now sailing its way to Graciosa Island, in the Azores.