Hotspots of Aiborne Lead Identified in Delhi, India (Publication and Press Coverage)

A new article by the Ault Group highlighting airborne lead hotspots in Delhi, India was recently published in Environmental Science and Technology, with the title of "Elevated Concentrations of Lead in Particulate Matter on the Neighborhood-Scale in Delhi, India As Determined by Single Particle Analysis". Professor Ault and first author Hongru Shen worked in collaboration with Prof. Thomas Peters (University of Iowa), Gary Casuccio (RJ Lee Group), and Prof. Naresh Kumar (University of Miami). Soon after the publication, this work was highlighted in a press release by Michigan News and reported on in the Hindustan Times, and Governance Now.

This work provides scientific evidence that emissions from informal recycling operations of used lead-acid battery, may contribute to localized high airborne lead concentrations in Delhi, India. Our collaborators (led by Prof. Kumar) collected the particle samples across Delhi (August - December 2008) using the passive samplers. RJ Lee Group characterized the samples using computer-controlled scanning electron microscopy with energy dispersive X-ray spectroscopy (CCSEM-EDX). During our data analysis at Michigan higher than expected lead-rich particles jumped out and caught our attention. Traditional sources, such as coal-fired power plants, leaded fuel, and resuspended road dust, were excluded after temporal and spatial analysis. With both physical and chemical properties of each single particle, we further confirmed informal recycling operations of used lead-acid battery as the likely source. For more details check out our paper and the press linked above!

MGU Symposium 2016

Bringing together graduate and undergraduate students from the disciplines of earth, oceanic, atmospheric, and space sciences, the Michigan Geophysical Union (MGU) symposium, held on central campus at U of M, was a success again in 2016! Hosted by the Climate and Space Sciences and Engineering (CLaSP) department, this 13th annual symposium fosters collaboration and works to generate interest among the various departments. This year, poster keyword bingo was played to further discussion among students from different programs and fields.

Graduate students Becky Craig and Amy Bondy presented posters at the symposium, as did undergraduate students Sydney Niles and Peter Tirella, all shown in the photos below with their posters. Congratulations to Becky for winning 2nd place in the chemistry section of the poster competition!

Amy Bondy presents on her latest manuscript, sea spray aerosol (SSA).

Sydney Niles presents on secondary organic aerosol (SOA) structure, which she also took to the ACS national meeting this spring.

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Peter Tirella presents his first-ever poster on surface enhanced Raman spectroscopy (SERS).

Becky Craig presents research on her latest publication, pH of aerosol single particles.

The Mobile Lab is Here!

A couple of weeks ago, Dr. Ault and I traveled to Fenton, Michigan to pick up our new Mobile Lab trailer. The trailer is 8.5 ft x 20 ft long and will allow us to embark on field campaigns with all of our instrumentation!

The first field study planned with the mobile lab will be to the University of Michigan Biological Station (UMBS) this July. Next winter, another field study to Kalamazoo, Michigan is planned.

Some of the instrumentation that will be aboard include:

Aerosol Time-of-Flight Mass Spectrometer (ATOFMS)

Chemical Ionization Mass Spectrometer (CIMS)

Ambient Ion Monitor- Ion Chromatograph (AIM-IC)

Dr. Andrew Ault (above) and Ryan Cook (below) in front of the brand new trailer!

In addition to plenty of room for our instruments, the trailer also has a large amount of storage!

We are looking forward to the currently planned field studies as well as future deployments of our mobile lab. This unique setup enables us to study atmospheric chemistry from a much different angle!

Water Center Funds Ault and Pratt Groups to Develop Mobile Laboratory

The Ault Group received a research grant from the University of Michigan Water Center to "advance water research capabilities at the University of Michigan". This collaboration with the Pratt Group will develop a mobile laboratory to to transport state-of-the-art instrumentation for field sampling of atmospheric aerosols produced from wave-breaking on the Great Lakes, a phenomenon we have termed "lake spray aerosol (LSA)" as the freshwater corollary to sea spray aerosol. This research builds on efforts with the Water Center to understand impacts of harmful algal blooms on air quality, in addition to water quality, for coastal communities on the Great Lakes. This research direction has grown in recent years with a general focus characterizing lake spray aerosol (aerosols produced by wave-breaking on the Great Lakes) both in the laboratory and in the field. This exciting project has produced two manuscripts that will be submitted shortly. 

The Lake Spray Aerosol Project and mobile lab to study it have received press from across Michigan in recent months.

The funding for this project was recently highlighted by the University of Michigan Biological Station (UMBS) (link).

In addition the general Lake Spray Aerosol (LSA) project was recently highlighted in the Grand Traverse Record Eagle (link).

We are looking forward to getting out and seeing what the Great Lakes tell us the next time the wind causes waves like this!

Photo Credit: Dave Sanford

New method for measuring pH of aerosol particles

An new article by the Ault Lab detailing a new method to measure the pH of individual aerosol particles was recently accepted by the Journal of Physical Chemistry A. Co-first author Rebecca Craig worked in collaboration with Dr. Joel Rindelaub (co-first author), a recent graduate from the Shepson Lab at Purdue University, and Lucy Nandy, a graduate student from the Dutcher Lab at the University of Minnesota, on the paper titled "Direct Measurement of pH in Individual Particles via Raman Microspectroscopy and Variation in Acidity with Relative Humidity." 

Aerosol particle acidity plays on important role in secondary organic aerosol (SOA) formation and other atmospheric processes, but has traditionally been difficult to measure as sulfate and bisulfate are not distinguishable by most methods used to determine aerosol chemical composition. This work used a Raman microspectrometer to probe the sulfate and bisulfate vibrational modes in laboratory generated aerosol particles, which were atomized from solutions of magnesium sulfate with varying concentrations of sulfuric acid. Using calibration curves relating integrated peak area to concentration for sulfate and bisulfate and their relationship with the acid dissociation constant, activity coefficients and pH could be determined for each aerosol particle.

Particles at ambient relative humidity had measured pH between 0.18 and 0.79. Continued probing of the particles as relative humidity was varied showed that aerosol particle pH increases as a function of increasing relative humidity and yielded pH measurements within the range of -0.68 to 1.33. This is consistent with the -0.5 to 3 range recently reported for ambient aerosol pH in the southeast United States from indirect methods. Future work will expand this method to other acid/base equilibrium systems to cover a wider range of pH, as well as work to apply this method to ambient aerosol particles.

Highlight in the U-M Water Center Fall Newsletter!

On Wednesday, November 18, 2015 the University of Michigan's Water Center sent their quarterly Newsletter in which one of our projects was highlighted related to lake spray aerosol, the freshwater equivalent of sea spray aerosol. Here is the link for those of you who would like to check it out: http://graham.umich.edu/water/newsletter/featured-projects-2015-11#ault-project, and they include a project factsheet as well.

Mobile Lab Design is Underway!

Design of an atmospheric mobile laboratory for the Ault and Pratt Labs has begun! Some instruments that are planned for deployment in the mobile lab are the following:

Aerosol Time-of-Flight Mass Spectrometer (ATOFMS)

Chemical Ionization Mass Spectrometer (CIMS)

Ambient Ion Monitor (AIM-IC)
 Aerosol Sizing Instrumentation (SMPS and APS)

Gas Phase Instrumentation (NOx and O3)

The goal is that the mobile lab, will be finished by January to be used for a winter study in collaboration with the Pratt Lab. It will come equipped with an A/C unit to keep the instruments from becoming to hot, a ramp to allow for easier loading and unloading of instruments and a roof platform to help with installment of the sampling setup. Potential other additions such as cabinets may also be part of the design.

The development process is currently taking over part of the Ault Lab as we do our best to get a spatial visualization of the mobile lab, by using tape to mark the area of the trailer. 

Foam boards are cut out to represent the different instruments.

Dr, Ault discussing the layout of the mobile lab design.

Dr. Pratt checking on the progress of the mobile lab design