Volatility properties of the ambient and laboratory generated aerosol

Atmospheric aerosols are indivisible from human life because of their pivotal role in air quality and climate. The aerosol's chemical, thermodynamic, and kinetic properties play a vital role in determining aerosol concentration and lifetime. In this work, the following aspects of aerosol volatility were investigated. We estimated the saturation vapor of the N-alkanes (C12 - C40), and carboxylic acids using measurement of gas-particles partitioning of these compounds in ambient aerosols. For normal alkanes with molecular weight between 275 - 375 g/mol, most of the estimated values were very close (within 20 %) to corresponding literature reported values. The measured total suspended particulate mass was comparable to the absorptive organic mass estimated using gas-particle partitioning theory. In addition, we evaluated a new method for estimation of enthalpy of vaporization using volatility tandem differential mobility analyzer (VTDMA) measurement of single components aerosol. The performed the a numerical evaluation of a new method to estimate uncertainties and sensitivity. Also this new technique was tested with adipic acid aerosol and enthalpy of vaporization was found to be 130 ± 3 kJ/mol, which is within the literature reported values. Volatility basis set (VBS) measurements were performed using a thermodenunder (TD) and a scanning mobility particle sizer at a sampling station in Reno, NV, USA during July-September 2017, December - February 2018, and June - July 2018. In addition to VBS, we estimated the volatility-based aerosol mixing state. Our observations show that aerosols were externally mixed most of the time. The extent of aerosol mixing state varies from season to season and among biomass burning events. In general, the extent of external mixing increases as the temperature of the measurement increases. The measured mean saturation vapor pressure was 10-1.05 µg/m3 with a standard deviation of 101.96 µg/m3 Based on the aerosol classification, aerosols are often found in low volatile and semi-volatile organic aerosol (LVOA + SVOA).

Level thesis:degree_level

Doctorate Degree

Year dc:date.issued

2021

Author dc:creator

• Bhattarai, Chiranjivi

Advisor dc:contributor.advisor

• Khlystov, Andrey

Committee members dc:contributor.committeemember

• Samburova, Vera
• Moosmuller, Hans
• Watts, Adam C
• Harris, Jr., Frederick

• Mixing state
• Partitioning
• Saturation Vapor Pressure
• TDMA
• Transpiration
• Volatility

Handle dc:identifier.uri

http://hdl.handle.net/11714/8014

OAI identifier oai:identifier

oai:scholarwolf.unr.edu:11714/8014