Investigating the Effects Of Atmospheric Aging on the Radiative Properties and Climate Impacts of Black Carbon AerosolEPA Grant Number: R835033
Title: Investigating the Effects Of Atmospheric Aging on the Radiative Properties and Climate Impacts of Black Carbon Aerosol
Investigators: Kroll, Jesse H. , Davidovits, Paul , Heald, Colette L.
Institution: Massachusetts Institute of Technology , Boston College
EPA Project Officer: Hunt, Sherri
Project Period: May 1, 2012 through April 30, 2015 (Extended to April 30, 2016)
Project Amount: $899,654
RFA: Black Carbon's Role In Global To Local Scale Climate And Air Quality (2010) RFA Text | Recipients Lists
Research Category: Global Climate Change , Climate Change , Air
Black carbon (BC) particles play a significant role in climate forcing, yet the effects of aging – atmospheric processes that affect the mass, size, shape, and chemical composition of aerosol particles – on their radiative properties are poorly constrained. This combined laboratory and modeling study will provide new insights into the detailed effects of atmospheric aging on the climate impacts of black carbon particles.
The proposed laboratory work will utilize a suite of state-of-the-art aerosol instrumentation to measure the changing radiative properties of BC-containing particles as a function of photochemical processing and relative humidity. Flame-generated BC particles will be characterized based on size, shape, chemical composition, and optical properties (e.g. extinction, scattering, and absorption), and these properties will be tracked as a function of several aging pathways (the condensation of inorganic species, the condensation of secondary organic aerosol, and the heterogeneous oxidation of the BC surface). Results will be compiled and condensed into a look-up table of key optical properties as a function of aerosol aging for use in atmospheric modeling. The modeling component of this project will incorporate these properties into a global model framework to investigate and quantify how such changes impact climate via direct radiative forcing (DRF).
This proposed project will result in fundamentally new insights into the role of black carbon in the climate system. The role of atmospheric aging will be investigated in detail, generating a detailed laboratory-based dataset containing the optical properties of BC-containing particles over a wide range of atmospheric conditions. The new global estimates of DRF by BC aerosol will be the first based on a realistic treatment of aerosol aging, leading to improved understanding of the policy-relevant relationships between emissions and regional and global climate. This work directly addresses two research topics of the solicitation: the determination of the impacts of long range transport of BC and related co-pollutants on climate forcing, and the development of new modeling tools to quantify and evaluate the climate effects of BC.