New Particle Formation and Growth in an Isoprene-Dominated Ozark Forest: From Sub-5 nm to CCN-Active Sizes

Journal Article · Tue Nov 25 04:00:00 EST 2014 · Aerosol Science and Technology, 48(12):1285-1298

DOI:https://doi.org/10.1080/02786826.2014.984801· OSTI ID:1188948

Yu, Huan; Ortega, John; Smith, James N.; Guenther, Alex B.; Kanawade, V. P.; You, Y.; Liu, Yiying; Hosman, Kevin P.; Karl, T.; Seco, R.; Geron, Chris; Pallardy, Stephen G.; Gu, Lianhong; Mikkila, Jyri; Lee, Shan-Hu

Particle Investigations at a Northern Ozarks Tower: NOx, Oxidant, Isoprene Research (PINOT-NOIR) were conducted in a Missouri forest dominated by isoprene emissions, from May to October 2012. This study presents results of new particle formation (NPF) and the growth of new particles to cloud condensation nuclei (CCN)-active sizes (~100 nm) observed from this field campaign. The measured sub-5 nm particles were up to ~20000 cm-3 during a typical NPF event. Nucleation rates J1 were relatively high (11.0±10.6 cm-3s-1), and one order of magnitude higher than formation rates of 5 nm particles (J5). Sub-5 nm particle events were observed on 64% of the measurement days, with a high preference in biogenic volatile organic compounds (BVOCs)- and SO2-poor northwesterly (90%) air masses than in BVOCs-rich southerly air masses (13%). About 80% of sub-5 nm particle events led to the further growth. While high temperatures and high aerosol loadings in the southerly air masses were not favorable for nucleation, high BVOCs in the southerly air masses facilitated the growth of new particles to CCN-active sizes. In overall, 0.4-9.4% of the sub-5 nm particles grew to CCN-active sizes within a NPF event. During a regional NPF event period that took place consecutively over several days, concentrations of CCN size particles increased by a factor of 5 in average. This enhanced production of CCN particles from new particles was commonly observed during all 13 regional NPF events observed during the campaign.

• Research Organization: Pacific Northwest National Laboratory (PNNL), Richland, WA (US)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 1188948
• Report Number(s): PNNL-SA-107541
• Journal Information: Aerosol Science and Technology, 48(12):1285-1298, Journal Name: Aerosol Science and Technology, 48(12):1285-1298
• Country of Publication: United States
• Language: English

Related Subjects

cloud condensation nuclei
isoprene
BVOC
new particle formation
nucleation