Ultraviolet light measurements (280–400 nm) acquired from stratospheric balloon flight to assess influence on bioaerosols

Abstract

Abstract Viable microorganisms collected from the Earth’s upper atmosphere are mysterious considering the intensely biocidal ultraviolet (UV) light conditions dominating rarefied air. Historically, most investigations examining the relationship between bioaerosols and UV conditions in the upper atmosphere have relied upon model-generated data. To address the shortage of in situ UV measurements in the upper troposphere and lower/middle stratosphere, we flew a meteorological balloon equipped with a UV radiometer and other core environmental sensors. The balloon payload launched from Illinois, USA, on October 6, 2018, and acquired UVA (315–400 nm) + UVB (280–315 nm) measurements for ~ 2 h up to 30.9 km. Above the atmospheric boundary layer, UVA + UVB values registered around 6 mW cm−2, results that were largely consistent with Tropospheric Ultraviolet–Visible model predictions. Performed in a low-cost, reusable manner with commercially available instruments, we show that reliable UV flux data can be acquired with meteorological balloon payload systems. This short communication provides relevant UVA + UVB results for aerobiology and astrobiology studies evaluating the survivability of microorganisms in the upper atmosphere.