OPEN ACCESS

Articles online

Analysis of a Multi-Year Record of Size-Resolved Hygroscopicity Measurements from a Rural Site in the U.S.

Category: Aerosol and Atmospheric Chemistry

Volume: 17 | Issue: 6 | Pages: 1489-1500
DOI: 10.4209/aaqr.2016.10.0443
PDF | Supplemental material | RIS | BibTeX

Manasi Mahish, Don Collins

  • Department of Atmospheric Sciences, Texas A&M University, College Station, Texas 77843-3150, USA

Highlights

50 nm particles least hygroscopic.
Size D < 100 nm: κday> κnight> κmorning, D > 100 nm: κday > κmorning> κnight.
D < 100 nm: κNPF event > κnon-event during day and night.
GF mode: Hygroscopic at large and small D, less-hygroscopic at intermediate D.
More internal mixing during daytime and summer months.


Abstract

Hygroscopic growth factor (GF) distributions of 13, 25, 50, 100, 200, and 400 nm particles measured with a Hygroscopic Tandem Differential Mobility Analyzer (HTDMA) from 2009 to 2012 at the Southern Great Plains (SGP) site in Oklahoma, U.S. were used to describe time of day- and annually-averaged hygroscopicity parameters (κ). A diel pattern was often observed with an average daytime κ that was higher than that at other times, especially on days with new particle formation (NPF) events. The average hygroscopicity of the smaller and larger particles at the tails of the measured size range was higher than that in between, with the minimum for each of the 4 years at 50 nm. This pattern is thought to result in part from addition of soluble inorganic and organic compounds formed through gas phase and aqueous phase reactions for the smaller and larger particles, respectively. The size dependence is reflected in the averaged κ and in the frequency with which GF distributions possessed modes categorized as nearly-hydrophobic, less hygroscopic, and hygroscopic. A hygroscopicity-based mixing state parameter, MShyg, defined as the ratio of the standard deviation (SD) of a measured GF distribution to the size specific threshold SD roughly separating internal and external mixtures, was used to study the diel and seasonal variation in particle mixing state. Internal mixtures were found to be more common during the daytime and during the summer, likely reflecting more rapid photochemical processing and growth at those times.

Keywords

Aerosol Hygroscopicity Growth factor Mixing state


Related Article

Effects of Wintertime Polluted Aerosol on Clouds over the Yangtze River Delta: Case Study

Chen Xu, Junyan Duan, Yanyu Wang, Mei Li, Tiantao Cheng , Hua Wang , Hailin Zhu, Xin Xie, Yuehui Liu, Yan Ling, Xiang Li, Lingdong Kong, Qianshan He, Hongli Wang, Renjian Zhang

Investigation of Diurnal Pattern of Generation and Resuspension of Particles Induced by Moving Subway Trains in an Underground Tunnel

Sang-Hee Woo, Jong Bum Kim, Gwi-Nam Bae , Moon Se Hwang, Gil Hun Tahk, Hwa Hyun Yoon, Se-Jin Yook
Accepted Manuscripts
DOI: 10.4209/aaqr.2017.11.0444
PDF

Two Way Relationship between Aerosols and Fog: A Case Study at IGI Airport, New Delhi

Pramod Digambar Safai , Sachin Ghude, Prakash Pithani, Somnath Varpe, Rachana Kulkarni, Kiran Todekar, Suresh Tiwari, Dilip Motiram Chate, Thara Prabhakaran, Rajendra Kumar Jenamani, Madhavan Nair Rajeevan
Accepted Manuscripts
DOI: 10.4209/aaqr.2017.11.0542
PDF

Trend in Fine Sulfate Concentrations and the Associated Secondary Formation Processes at an Urban Site in North China

Yating Zhang, Liang Wen, Jianmin Chen, Xinfeng Wang , Likun Xue, Lingxiao Yang, Liwei Wang, Zeyuan Li, Chuan Yu, Tianshu Chen, Wenxing Wang
;