INVESTIGATION OF THE SOURCES AND PROPERTIES OF ULTRAFINE PARTICLES IN IRVINE, CALIFORNIA

Aerosols, or particles suspended in air contribute to the haze that is perceived as smog. Ultrafine particles (those with diameters smaller than 100 nm), released into the air can influence climate and cause health problems such as bronchitis and asthma. In this project, the group reports the factors that contribute to the formation and evolution of ultrafine particles in the Irvine area. This research will provide insights into the magnitude and sources of this important pollutant. The study utilizes data from a scanning mobility particle sizer, which is used to obtain the particle size distributions. Meteorological data and emissions inventories compiled were also incorporated but regulatory agencies like the US EPA were used to infer the composition of the aerosol particles. Our analysis shows that wind direction is critical for determining the amount of ultrafine particles present. Extended periods of higher concentrations correlate best with winds from the NE, most remarkably during periods of strong Santa Ana winds. The dominant wind direction from the NE also corresponds to brief but intense bursts of ultrafine particles, suggesting major sources of these pollutants also exist along the coast North of Irvine.