Understanding Biomass Burning Aerosol via Integrated Analyses of Aerosol Mass Spectrometry Data from DOE Campaigns and ACRF Sites

Principal Investigator(s):
Qi Zhang, University of California, Davis

Biomass burning (BB) is one of the largest sources of aerosol particles in the atmosphere and a significant source of trace gases important to atmospheric chemistry. Organic aerosols from biomass burning sources (BBOA) are an important but poorly characterized component of the earth’s climate system. BBOA composition and life cycle processes are associated with enormous complexities and contribute significantly to model uncertainties. Hence it is important to improve the ability to simulate the concentration and properties (chemical, optical, and hygroscopic) of BBOA and the atmospheric aging processes that affect these properties. Here, we propose to analyze ambient data collected from the DOE Biomass Burning Observation Project (BBOP) field campaign and from a long term measurement site of the Atmospheric Radiation Measurement (ARM) program – the Southern Great Plains (SGP), where transported BB plumes and elevated BBOA episodes were frequently observed.

This project is aimed at 1) gaining detailed, quantitative understanding of the chemical and physical properties of BBOA and their chemical changes during atmospheric aging via advanced analysis of aerosol measurement data acquired at the summit of Mt. Bachelor (MBO) during the BBOP campaign and through integration with concurrent measurements of trace gases, particle properties, and meteorological conditions performed at MBO and from the G-1 aircraft; 2) gaining better understanding of BBOA properties and its roles in radiative forcing via analysis of routine data from the ARM long-term measurement sites; and 3) integrating the results from 1) and 2) into a global database of aerosol mass spectrometry and collaborate with modelers on evaluating and improving numerical model performance as part of the ASR program.

Specifically we will perform the following tasks:

• Analyze real-time aerosol data acquired with a thermodenuder (TD) – high resolution aerosol mass spectrometer (HR-AMS) and scanning mobility particle sizer (SMPS) system deployed at MBO to gain a thorough understanding of the time-dependent variations of aerosol properties during BBOP.
• Perform nanospray Desorption Electrospray Ionization (nano-DESI) mass spectrometry analysis of PM2.5 filters collected at MBO to understand the molecular composition of ambient organic aerosol (OA) during BBOP and identify mass spectral signatures for secondary organic aerosol (SOA) related to biomass burning emissions.
• Integrate the results from above two tasks with concurrent MBO and G-1 measurements of trace gases, particle properties, and meteorological conditions to evaluate the effect of wildfire combustion efficiency on BBOA concentrations and properties and to investigate SOA formation and the effect of atmospheric aging on BBOA characteristics.
• Develop and evaluate a value added product (VAP) for routine ACSM data from ARM long term measurement sites using the ME-2 solver to better deconvolve and quantify BBOA and track the long-term variations of distinct OA factors;
• Synthesize aerosol chemical information (including VAP OA factors), emission sources, back-trajectories, and collocated long-term measurements of aerosol optical and hygroscopic properties and atmospheric radiation at the ARM SGP site to better understand the climate properties and impacts of BBOA.

This research will lead to new knowledge about BBOA that is valuable for development of aerosol and chemical transport models. It is responsive to the DOE Atmospheric System Research (ASR) goal of “advancing the science of clouds, aerosols, precipitation and their interactions, with the potential to improve confidence in regional and global climate model projections.”