Abstract View
New Particle Formation (1-3nm) in Preschools in Nur-Sultan, Kazakhstan
MEHDI AMOUEI TORKMAHALLEH, Kamila Turganova, Tomiris Madiyarova, Zhuldyz Zhigulina, Enoch Adotey, Milad Malekipirbazari, Dept Chem & Mat Engr, Sch Engr & Dig Sci, Nazarbayev Univ
Abstract Number: 282
Working Group: Indoor Aerosols
Abstract
This study is the first report that provides evidence for the exposure to new particles in indoor environments with a focus on preschools, and demonstrates the major driving force for the formation of cluster mode particles (1-3nm). Cluster mode particles and ultraviolate absorbing particles (UVPM) were measured inside two modern preschools located in Nur-Sultan city of Kazakhstan from October 28 to November 27, 2019. Candle burning contributed to the emission of new particles as small as 2 nm. The major source of the new particle formation indoors was secondary organic aerosol (SOA) with particles below 2nm and concentrations above 107 particles/cm3. New particle formation (NPF) events were observed at different time of the day and also continuously throughout the day depending on the concentrations of the VOCs and independent of the ozone concentration in the range of 20 to 60 ppb. Below 20 ppb ambient ozone no major NPF event was observed. The major sources of volatile organic carbon (VOC) sources for the SOA formation were cleaning detergents, painting and gluing materials in the two preschools. Additionally, VOCs from frequent smoking near the preschool II served as the precursor of NPF events in the form of SOA. The infiltration of smoking fumes into the preschool II was well associated with the elevation of the ultraviolet PM (UVPM at 375 nm) concentrations inside the preschool II. The UVPM concentration reached as high as 7µg/m3 in one of the measurement days. Some changes in the training and cleaning programs may cause significant reductions in the exposure to the children to new particles. Such changes includes but are not limited to performing cleaning before and after the presence of the children in the preschools and conducting the art activities in the morning when the ozone concentration is lower compared to the afternoon.