Radon (²²²Rn) As a Priority Environmental Contaminant: A Comparative Geophysical Assessment Within the Multi-Pollutant Framework of Tirana, Albania

Abstract

Urban environments in South-Eastern Europe are subject to a complex burden of environmental contaminants spanning the atmospheric, hydrospheric, and pedospheric compartments. Within this multi-pollutant framework, radon-222 (²²²Rn) — a naturally occurring radioactive noble gas of geogenic origin — occupies a distinctive and frequently underestimated position. This paper presents a comparative geophysical and epidemiological assessment of ²²²Rn relative to the principal chemical and physical pollutants recorded in Tirana, Albania's capital city, integrating peer-reviewed measurement data from soil gas, indoor air, and water matrices. Indoor radon concentrations in Tirana's educational buildings and workplaces range from 24 to 1,058 Bq/m³, with soil-gas radon reaching values of 0.9–130.0 kBq/m³, substantially exceeding the Albanian national reference level of 300 Bq/m³ in critical sectors. Contextualised against outdoor air pollutants (PM₂.₅ ~47 µg/m³; NO₂ ~34 µg/m³; PM₁₀ ~55 µg/m³), heavy metal soil contamination (Ni: mean 305.9 mg/kg; Cr: 174.2 mg/kg), and microbiological water quality deficiencies, radon emerges as the single contaminant with the highest documented carcinogenic potency per unit exposure in the non-smoking population, responsible for an estimated 3–14% of all lung cancer cases nationally. Predictive climate modelling under RCP 8.5 projects a 10–20% increase in indoor ²²²Rn by 2050. The paper argues that radon demands immediate policy prioritisation within Albania's national environmental strategy and European integration frameworks, and outlines evidence-based recommendations for monitoring and mitigation.