Interview to Jasper Kirkby - CLOUD experiment's results on new mechanism behind urban smog

CLOUD experiment interview of Jasper Kirkby spokesperson Rapid growth of new atmospheric particles by nitric acid and ammonia condensation Nanoscale particles have been observed to form and grow in the atmospheres of many cities, contradicting our understanding of particle-formation processes. Experiments now reveal a possible explanation for this mystery. New-particle formation is a major contributor to urban smog1,2, but how it occurs in 3 cities is often puzzling. If the growth rates of urban particles are similar to those found in cleaner environments (1–10 nanometres per hour), then existing understanding suggests that new urban particles should be rapidly scavenged by the high concentration of pre-existing particles.