A Field Study on Background Radiation Variability with Elevation in Eastern Nepal

Bishal Neupane 

This research investigates how environmental radioactivity varies with altitude in the
diverse landscapes of Eastern Nepal. Employing two calibrated Geiger–Müller (GM)
counters, background radiation was recorded as counts per minute (cpm) across selected
sites in the districts of Dhankuta, Panchthar, Taplejung, and Ilam. Data were geo-
referenced using GPS to correlate radiation levels with elevation. The analysis reveals
a modest but consistent rise in background radiation with increasing altitude. This
trend aligns with the established influence of cosmic ray intensity, which increases at
higher elevations due to reduced atmospheric shielding. Local geological variations such
as rock composition and naturally occurring radioactive isotopes are also identified as
potential contributors to deviations from the trend. The resulting dataset serves as a
baseline for future environmental monitoring efforts in Nepal and offers insights into both
the cosmic and terrestrial components of background radiation in mountainous regions.
These findings have implications for public health assessment, geological surveys, and
environmental policy development.