Determination of the Optical Properties of Secondary Organic Aerosol Particles

The enhanced greenhouse effect is currently considered to be our most important global environmental problem. While the magnitude of radiation absorbed by greenhouse gases is known to a high certainty, the absorption of radiation by atmospheric aerosol particles is not. In the initial Visiting Faculty Program application, we proposed the use of an ultraviolet-visible (UV/Vis) spectrometer equipped with a liquid waveguide capillary flow cell to determine the extent to which secondary organic aerosol particles (SOA) absorb visible light. Early in the research period, the UV/Vis technique was optimized for three solvent systems (methanol, water and 0.1 M hydrochloric acid). Using the optimized UV/Vis technique optical properties such as mass specific absorption cross-section and imaginary refractive index were determined for SOA dissolved in different solvent systems. The end result of the UV/Vis studies is the inclusion of SOA optical properties into climate models developed at the Pacific Northwest National Laboratory (PNNL). This knowledge will help to improve climate models, which currently do not include the effect of SOA. We also utilized Fourier Transform Infrared Spectroscopy to help elucidate the chemical composition of SOA. Finally, an experimental method was developed to determine the peroxide content of SOA. It is expected that these studies will connect the chemical composition of SOA to their optical properties. The research carried out at PNNL will be included in two undergraduate senior theses at Concordia University - Portland (CU). It is also expected that this research will be included in a peer-reviewed journal article. It is our hope that success of our work will result in future collaborations between PNNL and CU students

Optical Properties of Secondary Organic Aerosols

It is well known that the increased warming effect due to greenhouse gases is a major environmental concern. While the amount of solar radiation absorbed by greenhouse gases is known to a high certainty, the amount absorbed or reflected by secondary organic aerosols (SOA) is not. Our study aimed to discover how much radiation SOA particles absorb between ~200 and 800 nm. The SOA were created in one of two temperature controlled Teflon chambers within Dr. John Shilling’s lab at the Pacific Northwest National Laboratory (PNNL) and were collected on 47 mm Teflon filters. We used an ultraviolet-visible (UV/Vis) spectrometer equipped with a liquid waveguide capillary flow cell to determine the amount of radiation SOA absorbs at various wavelengths. We developed and optimized UV/Vis procedures for SOA dissolved in three solvents: water, methanol, and 0.1 M hydrochloric acid. We also successfully determined the mass absorption coefficients and imaginary refractive indices for the generated SOA. These values will be used in climate models developed at PNNL

Optical Properties of Secondary Organic Aerosols Using Ultraviolet/Visible Spectroscopy

It is well known that the increased warming effect due to greenhouse gases is a major environmental concern. While the amount of solar radiation absorbed by greenhouse gases is known to a high certainty, the amount absorbed by secondary organic aerosols (SOA) is not. Our study aimed to discover how much radiation SOA particles absorb between ~200 and 800 nm. The SOA were created in one of two temperature controlled Teflon chambers within Dr. John Shilling’s lab at PNNL and were collected on 47 mm Teflon filters. We used an ultraviolet-visible (UV/Vis) spectrometer equipped with a liquid waveguide capillary flow cell to determine the amount of radiation SOA absorbs at various wavelengths. We developed and optimized UV/Vis procedures for SOA dissolved in three solvent systems: water, methanol, and 0.1 M hydrochloric acid. We also successfully determined the mass absorption coefficient values and imaginary refractive indices for the generated SOA. These values will be used in climate models developed at PNNL

Optical Properties of Secondary Organic Aerosols Using Ultraviolet/Visible Spectroscopy

It is well known that the increased warming effect due to greenhouse gases is a major environmental concern. While the amount of solar radiation absorbed by greenhouse gases is known to a high certainty, the amount absorbed by secondary organic aerosols (SOA) is not. Our study aimed to discover how much radiation SOA particles absorb between ~200 and 800 nm. The SOA were created in one of two temperature controlled Teflon chambers within Dr. John Shilling’s lab at PNNL and were collected on 47 mm Teflon filters. We used an ultraviolet-visible (UV/Vis) spectrometer equipped with a liquid waveguide capillary flow cell to determine the amount of radiation SOA absorbs at various wavelengths. We developed and optimized UV/Vis procedures for SOA dissolved in three solvent systems: water, methanol, and 0.1 M hydrochloric acid. We also successfully determined the mass absorption coefficient values and imaginary refractive indices for the generated SOA. These values will be used in climate models developed at PNNL

Optical Properties of Secondary Organic Aerosols

It is well known that the increased warming effect due to greenhouse gases is a major environmental concern. While the amount of solar radiation absorbed by greenhouse gases is known to a high certainty, the amount absorbed or reflected by secondary organic aerosols (SOA) is not. Our study aimed to discover how much radiation SOA particles absorb between ~200 and 800 nm. The SOA were created in one of two temperature controlled Teflon chambers within Dr. John Shilling’s lab at the Pacific Northwest National Laboratory (PNNL) and were collected on 47 mm Teflon filters. We used an ultraviolet-visible (UV/Vis) spectrometer equipped with a liquid waveguide capillary flow cell to determine the amount of radiation SOA absorbs at various wavelengths. We developed and optimized UV/Vis procedures for SOA dissolved in three solvents: water, methanol, and 0.1 M hydrochloric acid. We also successfully determined the mass absorption coefficients and imaginary refractive indices for the generated SOA. These values will be used in climate models developed at PNNL

Composition of Secondary Organic Aerosols

The enhanced greenhouse effect is considered one our greatest global environmental problems. The amount of radiation absorbed by greenhouse gases is known to high certainty. However, absorbance from atmospheric aerosols particles is not. This study was conducted to determine the chemical composition of secondary organic aerosol particles (SOA) and to determine the compositional effect on their optical properties. The SOA were created in a temperature controlled chamber at Pacific Northwest National Laboratory (PNNL) in Richland, WA and collected on filters. The SOA were then analyzed for chemical composition using Fourier Transform Spectroscopy (FTIR). Analysis of the IR spectra revealed specific chemical functional groups degraded during storage while others amplified. The area under select peaks was calculated and a relationship between storage time and peak area was modeled

Optical Properties of Secondary Organic Aerosols

It is well known that the increased warming effect due to greenhouse gases is a major environmental concern. While the amount of solar radiation absorbed by greenhouse gases is known to a high certainty, the amount absorbed by secondary organic aerosols (SOA) is not. The experimental procedure used to measure the amount of radiation absorbed by SOA was optimized using fulvic acid. The optimized method was then used to measure how much radiation SOA absorb between ~200 and 800 nm. Using this data, mass absorption coefficient (MAC) values at 405 nm and imaginary refractive indexes (k) were calculated. These values will be used to help improve climate models developed at PNNL that currently do not take into account radiation absorbed by SOA

Workshop U.S.- Italy on Sediment Managment Research: A Cleaner Scenario

Research Questions: What is the chemical composition of SOA? Does SOA absorb UV/Vis radiation? If SOA does absorb UV/Vis radiation, how strong of an absorber is it

Optical Properties of Secondary Organic Aerosols

It is well known that the increased warming effect due to greenhouse gases is a major environmental concern. While the amount of solar radiation absorbed by greenhouse gases is known to a high certainty, the amount absorbed by secondary organic aerosols (SOA) is not. The experimental procedure used to measure the amount of radiation absorbed by SOA was optimized using fulvic acid. The optimized method was then used to measure how much radiation SOA absorb between ~200 and 800 nm. Using this data, mass absorption coefficient (MAC) values at 405 nm and imaginary refractive indexes (k) were calculated. These values will be used to help improve climate models developed at PNNL that currently do not take into account radiation absorbed by SOA

Composition of Secondary Organic Aerosols

The enhanced greenhouse effect is considered one our greatest global environmental problems. The amount of radiation absorbed by greenhouse gases is known to high certainty. However, absorbance from atmospheric aerosols particles is not. This study was conducted to determine the chemical composition of secondary organic aerosol particles (SOA) and to determine the compositional effect on their optical properties. The SOA were created in a temperature controlled chamber at Pacific Northwest National Laboratory (PNNL) in Richland, WA and collected on filters. The SOA were then analyzed for chemical composition using Fourier Transform Spectroscopy (FTIR). Analysis of the IR spectra revealed specific chemical functional groups degraded during storage while others amplified. The area under select peaks was calculated and a relationship between storage time and peak area was modeled