Breakout Summary Report

ARM/ASR User and PI Meeting

2 - 6 May 2016

Session Title: New Particle Formation
Session Date: 2 May 2016
Session Time: 1:00 PM - 3:00 PM
Number of Attendees: 0
Summary Authors: Jim Smith

Breakout Description

The primary objective of the breakout was to build and strengthen collaborations among DOE ASR New Particle Formation (NPF) researchers. This work requires interactions among experimentalists, theorists, and modelers. The discussion was organized around the following themes:
1. Overview of the recent white paper "New Particle Formation: Future Research Needs," which was prepared for ASR leadership recently as input for the new Science Plan
2. Discussion of ongoing ASR NPF collaborations
3. Ideas for new ASR NPF collaborations.
Much of the discussion focused on identifying instruments, sampling, and deployment strategies that are relevant to NPF research.

Main Discussion

Instrumentation

The following instruments/measurements are most beneficial to the research objectives of the NPF Focus Group. These need to be co-located to create a complete data set. The measurements marked with an “*” are those that we believe to be new.
• Size distribution (1* nm – 1 μm)
• Hygroscopicity (HTDMA) and CCN activity (CCN-100/200)
• Particle number concentrations for sizes greater than 3 and 10 nm (e.g., TSI 3772 & 3776 CPCs)
• PM1 composition (ACSM)
• VOCs* (e.g., PTR-MS)
• [NOx]*
• [O3]*
• [SO2]
In addition, the group agreed that very little is known about the sources of amines, ammonia, and low-volatility gas-phase precursors. We need to understand and map these in order to properly predict NPF. This involves measurements of:
• Gas-phase bases: ammonia, amines
• low- and “extremely low” volatility inorganic and organic compounds

Sampling

The NPF Focus Group strongly recommends obtaining vertical distributions of trace gases and aerosol properties. This could be performed using tall towers, tethered balloons, or aircraft. The periodic Cessna aircraft flights over SGP provide one possible opportunity.
 
Deployments

• Long-term observations are key components of the deployment of any instrument suite that addresses the needs of NPF research. This is not always possible due to the nature of the instrumentation (e.g., those that require full-time monitoring).
• IOPs, featuring specialized measurements that may require more supervision, should ideally be coupled with long-term observations when possible.
• The group recognized the utility of observations from remote-sensing instruments (e.g., ceilometer, Doppler lidar) in connecting ground-based observations to climate impacts. Because of this, it is important to deploy instruments suites for periods that span seasons to years to sites that include remote-sensing instruments.

Future Plans

• SGP will remain an outstanding site for studying NPF. HI-SCALE will be an important campaign for NPF research. Current plans to deploy a comprehensive suite of instruments for studying NPF during HI-SCALE Phase II are proceeding.
• Long-term measurements initiated previously should continue at the SGP site. They are proving to be a great resource for NPF research.
• Looking into the future, there is growing interest in a NPF-focused field campaign in the California Central Valley with the G-1, as a follow-on to CARES and complement to HI-SCALE.

Action Items

• NPF leadership will inquire as to whether the white paper "New Particle Formation: Future Research Needs," can appear on the NPF focus group web site for the benefit of group members.
• A study of the vertical structure of the atmosphere and its impact on NPF-climate coupling is currently underway by Smith et al.
• A collaborative chamber campaign involving the PNNL chamber is currently being explored by Smith and Shilling.