How city gases condense into particulate matter
In the air of many metropolises, nanometer-sized airborne particles are produced. However, previous observations of their growth contradict the common understanding of how the particles form. Now experiments offer a possible explanation.
A research group led by Mingyi Wang from Carnegie Mellon University in Pittsburgh (USA) has discovered how particles in the air grow faster than previously thought due to the condensation of ammonium nitrate - under conditions that are typical in many cities in winter to rule. Although the authors of the study made their observations in a laboratory, they argue that very similar conditions can temporarily prevail in large cities.
Particulate matter is a significant factor in air quality in many major cities around the world, as medical professionals link it to numerous diseases. In addition, it interacts with solar radiation and clouds and thus influences the regional climate. The small particles not only contribute to the total number of particles in the air, they can also serve as nuclei for clouds. In order to predict how particulate matter affects he alth and the surrounding climate, it is therefore important to know how the particles are formed and grow.
In recent years, researchers have found out more and more about how suspended matter forms in the air. However, with their current understanding of the early stages of particle growth - the crucial phase in which an initial collection of molecules grows so large that a suspended particle is actually formed - they cannot explain why new fine dust particles form in large cities…