ATMOSPHERIC PARTICLE IDENTIFICATION AND CHARACTERIZATION OF FIELD COLLECTED SAMPLES
Atmospheric particles originate from all over the globe with wildly different sources such as sea spray aerosols of the ocean, mineral dust from deserts, biogenic emissions from forests, anthropogenic emissions of urban and industrial areas, volcanic eruptions, and many more. All of these particles can then be transported during which aging can occur where the external and internal chemical composition of particles and drastically be altered in which their physiochemical properties change or new particles as a whole are formed. Understanding what can cause this aging and correctly identifying how these particles change is vital for assessing climate in local areas.
Chapter 3 focuses on dry intrusion (DI) and non-DI periods where vertical mixing of air occurs and allows for long range transport of particles. DI periods introduces populations of aged particles from far away sources into local regions. Identification and chemical characterization is performed for both of these periods to highlight the changes the DI period introduces in regards to particle morphology, chemical composition and lifetime. Analysis was performed via computer controlled scanning electron microscopy (CCSEM) for external information of the particles and scanning transmission x-ray microscopy (STXM) was used for internal information. The combination of these two techniques allows for a complete and thorough understanding of the particles during the two periods.
Chapter 4 covers the first experiment done on a newly constructed cryogenic cooling cart which was created in the hopes to identify individual ice nucleating events of particles in situ when mimicking real world atmospheric conditions through temperature and humidity control.
- Master of Science
- West Lafayette