Viruses are falling from the skies

To determine how many viruses fall from the troposphere each day, automatic collectors were placed at two different locations in the Sierra Nevada Mountains of Spain at 1.75 km above sea level. Placing the collectors at this height allows sampling of air above the atmospheric boundary layer (pictured – image credit). Samples were retreived every 1-2 weeks over the course of two years and analyzed for the presence of viruses by flow cytometry after purification by centrifugation. The results show that billions of viruses fall from the atmosphere each day: from 0.3 to 3.8 x 109 per square meter. Most (69%) of the viruses that descend from the atmosphere are attached to dust or organic aggregates. The rate of falling viruses was not substantially different over the course of the study nor between the two different sites.See it on Scoop.it, via Viruses, Immunology & Bioinformatics from Virology.uvic.ca
Viruses are falling from the skies
Source: Viral Bioinformatics