Research Areas

Urban Nanoparticles

The goal of this project is to measure the chemical composition of ambient nanoparticles and to use this information to determine the impact of motor vehicle emissions on air quality.

Example Publication:

C.A. Zordan, S. Wang, and M.V. Johnston, “Time-Resolved Chemical Composition of Individual Nanoparticles in Urban Air”, Environmental Science and Technology (2008) 42, 6631-6636.

New Particle Formation

The goal of this project is to study the mechanisms of particle formation and growth in air.

Example Publication:

B.R. Bzdek, D.P. Ridge, M.V. Johnston “Size-Dependent Reactions of Ammonium Bisulfate Clusters with Dimethylamine” Journal of Physical Chemistry A (2010) 114, 11638-11644.

Secondary Organic Aerosol

The goal of this project is to elucidate chemical processes such as oligomer formation and oxidation that alter the volatility and optical properties of organic molecules in ambient particles.

Example Publication:

Y. Gao, W.A. Hall IV, M.V. Johnston “Molecular Composition of Monoterpene Secondary Organic Aerosol at Low Mass Loading” Environmental Science and Technology (2010) 44, 7897-7902.

Engineered Nanoparticles in the Environment

The goal of this project is to determine the fate of aqueous nanoparticles as they pass through a waste water treatment facility.

Example Publication (of methodology):

K. Adou and M.V. Johnston, “Flow Interface for Charge-Reduced Electrospray of Nanoparticle Solutions”, Analytical Chemistry (2009) 81, 10186-10192.

Aerosol Mass Spectrometry

This goal of this work is to develop instrumentation to measure the composition of individual particles in air. Current emphasis is on nanoparticle analysis with the nano aerosol mass spectrometer (NAMS) and coarse particle analysis with the real time single particle mass spectrometer (RSMS).

Example Publication:

S. Wang, C.A. Zordan, and M.V. Johnston, “Chemical Characterization of Individual, Airborne Sub-10 nm Particles and Molecules”, Analytical Chemistry (2006) 78, 1750-1754.

Recent Reviews and Introductory Publications:

B.R. Bzdek and M.V. Johnston, “New Particle Formation and Growth in the Troposphere”, Analytical Chemistry (2010) 82, 7871-7878.

M.V. Johnston, S. Wang, and M.S. Reinard, “Nanoparticle Mass Spectrometry: Pushing the Limit of Single Particle Analysis”, Applied Spectroscopy (2006) 60, 264A-272A.

D.G. Nash, T. Baer, and M.V. Johnston, “Aerosol Mass Spectrometry: An Introductory Review”, International Journal of Mass Spectrometry (2006) 258, 2-12.