Assessment of C-14 and CO₂ in Atmospheric Air and Pine Needles in Gliwice, Poland
(under review…Radiocarbon):
A comprehensive study monitoring carbon dioxide levels and radiocarbon concentrations in an urban environment from August 2023 to July 2024.
Research Overview
Location
Gliwice, Silesia, Poland - third largest city in Upper Silesian metropolitan area with 180,000 inhabitants
Timeline
August 2023 to July 2024 with monthly integrated samples and seasonal pine needle collection
Methods
CARBOCAP GMP343 for CO₂ analysis, CRDS, MICADAS for ¹⁴C/¹²C ratio, liquid scintillation counter for needles
Monitoring Station Setup
Air Sampling System
New laboratory stand established at Silesian University of Technology campus in city center. Air intake positioned 20 meters above ground on faculty building roof.
Automatic sampling system with two 50L alumina-coated polyethylene bags, mass flow controller, and KNF pump with Viton membrane ensuring no isotopic fractionation.
Pine Needle Collection
Scots Pine (Pinus sylvestris L.) samples from ~20-year-old trees growing near main highway, less than 50m distance.
Needles collected quarterly from crown, separated by age (1-3 years old), approximately 100 grams per sample.
CO₂ Concentration Results
Monthly CO₂ mole fraction varied from ~430 to 470 ppm, showing seasonal patterns with higher concentrations in winter months when anthropogenic emissions dominate.
Radiocarbon Variations
Key Findings
¹⁴C in air samples varied randomly from -55 to -24‰ over the study period
Clear seasonal trend observed: ¹⁴C decreased during winter compared to other seasons, indicating increased fossil fuel combustion impact.
Comparison with Jungfraujoch reference site (Swiss Alps) showed fluctuation between -14.87 to -7.89‰, confirming local fossil fuel influence in Gliwice.
2.5%
Fossil Fraction
Estimated percentage of CO₂ from fossil fuels
11
Fossil CO₂
ppm from fossil fuel sources
Planetary Boundary Layer Impact
1
Daytime Dynamics
Surface heating enhances convection and turbulent mixing. Deep boundary layer dilutes CO₂ emissions in large air volume, decreasing near-surface concentrations.
2
Nighttime Accumulation
Surface cooling creates temperature inversion, weakening turbulence. Shallow boundary layer traps CO₂ from respiration and emissions, causing sharp concentration increases.
3
Seasonal Patterns
PBL height strongly influences CO₂ concentration year-round, especially in summer and spring. At midnight, CO₂ and PBL trends align; at midday, they show opposite patterns.
Biosphere vs. Atmosphere
Winter & Early Spring
Anthropogenic emissions from local and regional sources play more significant role. Minimal photosynthesis and plant respiration before growing season begins.
Daily CO₂ variations influenced by biological processes, anthropogenic activities (traffic, heating), atmospheric transport, and planetary boundary layer dynamics.
Pine Needle Analysis
01
Sample Preparation
Needles separated by age (1-3 years), treated with acid-alkali-acid process, converted to benzene for liquid scintillation counting.
02
Radiocarbon Measurement
¹⁴C concentration determined using Quantulus 1220 LSC. Mean F¹⁴C from all samples: 99.80(70) pMC.
03
Temporal Resolution
Quarterly collection (2021-2024) with 3-month resolution. No significant differences between seasons or needle ages within uncertainty ranges.
Key Conclusions
Urban Carbon Cycle
Approximately 11 ppm (2.5%) of atmospheric CO₂ in Gliwice originates from fossil fuels. Monitoring reveals complex interplay of emissions, seasonal fluctuations, and biosphere interactions.
PBL Influence
Planetary boundary layer height strongly controls short-term CO₂ fluctuations. Shallow layers increase concentrations; deep layers decrease them, with patterns varying by time of day.
Biosphere Archives
Pine needles show different radiocarbon composition than atmospheric air. Suess effect observed in both archives, though needles show enrichment compared to air samples.
Historical Context
Current results differ from 2012-2014 observations of very high ¹⁴C in needles, suggesting previous enrichment was a localized, time-limited phenomenon.
Future Directions
Continued Monitoring
Long-term surveillance essential for understanding local carbon cycle and environmental interactions. Recent policy changes in energy sector make CO₂ data valuable for comparing urban and natural carbon cycles.
Higher temporal resolution needed to capture full range of daily and seasonal variations in both atmospheric and biosphere archives.
Research Support
Study supported by EU grant for Silesia 2021-2027, MONCO2 project (Modern methods of monitoring CO₂ level and isotopic composition).
Who done what;)
Barbara Sensuła-idea, sampling, preparation of the samples for analysis up to convertion of benzen or graphite targets, measurements, data collection, analysis and presentation of the results, acquiring funding
Jakub Bartyzel & Miroslaw Zimnoch- creation of sampler, interlaboratory calibration, scientific discussion…
Alicja Ustrzycka- MICADAS operation
Adam Michczyński-Quantulus operation
under review (Radiocarbon)
