Anthropogenic Extremely Low Volatility Organics (ELVOCs) Govern the Growth of Molecular Clusters Over the Southern Great Plains During the Springtime
[1];
[2];
[1];
[3];
[4];
[4];
[1];
[1];
[1];
[1];
[5];
[5];
[6];
[8]
- Pacific Northwest National Laboratory Richland WA USA
- Pacific Northwest National Laboratory Richland WA USA, Now at Lawrence Berkeley National Laboratory Berkeley CA USA
- State Key Joint Laboratory of Environmental Simulation and Pollution Control School of Environment Tsinghua University Beijing China
- Department of Atmospheric Science Colorado State University Fort Collins CO USA
- Office of Research and Development US Environmental Protection Agency Research Triangle Park NC USA
- Department of Environmental Toxicology University of California Davis CA USA, Agricultural and Environmental Chemistry Graduate Group University of California Davis CA USA
- Department of Environmental Toxicology University of California Davis CA USA
- State Key Joint Laboratory of Environmental Simulation and Pollution Control BIC‐ESAT and IJRC College of Environmental Sciences and Engineering Peking University Beijing China
Abstract New particle formation (NPF) often drives cloud condensation nuclei concentrations and the processes governing nucleation of molecular clusters vary substantially in different regions. The growth of these clusters from ∼2 to >10 nm diameters is often driven by the availability of extremely low volatility organic vapors (ELVOCs). Although the pathways to ELVOC formation from the oxidation of biogenic terpenes are better understood, the mechanistic pathways for ELVOC formation from oxidation of anthropogenic organics are less well understood. We integrate measurements and detailed regional model simulations to understand the processes governing NPF and secondary organic aerosol formation at the Southern Great Plain (SGP) observatory in Oklahoma and compare these with a site within the Bankhead National Forest (BNF) in Alabama, southeast USA. During our two simulated NPF event days, nucleation rates are predicted to be at least an order of magnitude higher at SGP compared to BNF largely due to lower sulfuric acid (H 2 SO 4 ) concentrations at BNF. Among the different nucleation mechanisms in WRF‐Chem, we find that the dimethylamine (DMA) + H 2 SO 4 nucleation mechanism dominates at SGP. We find that anthropogenic ELVOCs are critical for explaining the growth of particles observed at SGP. Treating organic particles as semisolid, with strong diffusion limitations for organic vapor uptake in the particle phase, brings model predictions into closer agreement with observations. We also simulate two non‐NPF event days observed at the SGP site and show that low‐level clouds reduce photochemical activity with corresponding reductions in H 2 SO 4 and anthropogenic ELVOC concentrations, thereby explaining the lack of NPF.
- Sponsoring Organization:
- USDOE
- Grant/Contract Number:
- SC0021208; SC0019000
- OSTI ID:
- 2475238
- Journal Information:
- Journal of Geophysical Research. Atmospheres, Journal Name: Journal of Geophysical Research. Atmospheres Journal Issue: 21 Vol. 129; ISSN 2169-897X
- Publisher:
- American Geophysical Union (AGU)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
Similar Records
Multiple new-particle growth pathways observed at the US DOE Southern Great Plains field site
New particle formation leads to cloud dimming