The DELTA Group

for the Detection and Evaluation of the Long-Range Transport of Aerosols

See our latest photos
from the Roseville site!

Department of Applied Science

World Trade Center
Who We Are
DQAP Download




A Few of Our Projects

| New | Current | Past |



Roseville Rail Yard

Local Area High Schools and Breathe California - Sacramento Emigrant Trails

Lake Tahoe, TERC collaboration


Lake Tahoe, CalTrans




Roseville Rail Yard

Fine particles from the Denio's Site downwind of rail yard. The dark lines that you see are composed primarily of diesel exhaust. Dr. Cahill with sample of larger size particles. The light coloration in this stage is indicative of dust particles.
Project manager Nick Spada and Dr. Tom Cahill Junior testing their capabilities in sampling organics using a Lundgren sampler.
Dr. David Barnes and Dr. Cahill changing out drums at the upwind Johnson Pool site.
Fine particles from the upwind Johnson Pool sampler.
Placer County meteorological data monitor, Johnson Pool, with the Roseville Rail Yard seen in the background.
Photographs by Rachel DuBose


Local Area High Schools and Breathe California - Sacramento Emigrant Trails
 For a period of six weeks in January and February, Tom Cahill helped guide and train local area high school students in air sampling using the DELTA Group's DRUM technology. The students also tracked weather conditions and conducted a traffic count of vehicles on nearby roads and in parking lots to correlate with the air quality data they obtained. After they conduct the full series of analyses, the students are then able to suggest improvements that will promote better air quality on their campuses. Burbank High students and staff with Tom Cahill and representatives from the American Lung Association Sacramento-Emigrant Trails.

Tom Cahill shows where the particulates impact Tom Cahill demonstrates how the DRUM sampler functions Burbank High Students and Staff with Tom Cahill and Representatives of Breathe California - Sacramento Emigrant Trails


Lake Tahoe, TERC collaboration

Continuous sampling with PM10 inlet across 8 size ranges.  Currently archived samples from May 2, 2007 through July 2007









8-DRUM sampler TERC roof

Incline Village, NV

May 2, 2007






Lake Tahoe CalTrans (under construction)
The DELTA Group is
assisting CalTrans in the evaluation of particles generated by alternative de-icing protocols on Highway 50 at South Lake Tahoe, CA, winter, 2003-2004, and their projected effects on the clarity of the lake.
We were able to take advantage of archived samples from prior experiments at Lake Tahoe since aerosols were measured at South Lake Tahoe near Hwy 50 (just west of Bijou) from Jan 11, 2002 through April 16, 2002, as part of a TRPA (Tahoe Regional Planning Agency) study of fine particle impacts on visibility and lake clarity. However, to continue the study, we installed two samplers near the lake with the current CalTrans funding.
We collected aerosols in 8 size modes, 10 μm to 0.09 μm, at the TRPA South Lake Tahoe (SOLA) site and the ARB Sandy Way site, upwind and downwind of Highway 50. This sampling began Dec. 3, 2002, picked up again on Dec. 3, 2004, and will continue through Jan 15, 2004.
We also collected similar aerosol samples, at the TRPA South Lake Tahoe (SOLA) site from Jan 15 to April 15, 2004.
Later, we will analyze historical samples taken in the Period Feb - April, 2002 at SOLA to match the 2004 data.
Finally, we will correlate these data with local and regional meteorology, CalTrans operations, and other factors.   
This contract was extended into 2006 more sampling was done in fall 2005, and we submitted the final report in September, 2006.

Sampling substrate with black strips of particulate matter collected overnight at Tahoe Sampler, Highway 50 and Lake Tahoe


One of the great treasures of climate research is the data from the Greenland ice cores. These ice cores, from the sheet which holds a large fraction of the earth's fresh water, possess layers of materials other than just ice. One such material found in the core samples is mineral dust.
If the mineral dust layers could be correlated with atmospheric mineral aerosols, then the cores could provide further information on the aerosols as a function of time. This information would greatly aid in the paleo-climatic record.
Under a subcontract with U.C. Merced and with Professor Roger Bales as the Principal Investigator, the DELTA Group agreed to design and build a DELTA Group 8-DRUM sampler modified to operate during  an entire year at the Greenland ice cap. The samples are currently being analyzed for mass and elemental concentrations using DELTA Group techniques.



he Tracking of Asian Aerosol Episodes using Time, Size, and Compositionally Resolved Analyses at Surface Sites during ACE-Asia
Thomas A. Cahill, Steven S. Cliff, and Michael Jimenez-Cruz, UC Davis. Kevin D. Perry and Wang Ming-Xing, Meteorology Department, San Jose State University; Academy of Science, Beijing

Tracking aerosols across the Pacific during ACE-Asia. The values from Cheju Kosan are divided by 5. Note that peak Silicon (soil) values during the April dust storm at Adak Island, Mauna Loa, and Crater Lake NP decline only modestly versus distance, and that the March dust storm was not seen at either Adak Island or Mauna Loa Observatory.



Preliminary data (relative) from the cruise of the R/V Ron Brown. The zero values were caused by the automatic wind direction sensor to avoid pollution from ship exhaust.



On the left,  Chinese dust storm.
On the right, a clear day.

On the left, a Chinese coal-fired power plant. On the right, dirty filters from China v. the clean (on the bottom) from Hawaii.

Strips showing polluted Chinese air on the left, compared to cleaner Hawaiian air on the right


The purpose of the project was to characterize aerosols downwind of Cincinnati freeways as a function of distance from the freeway and season of the year. More information will be published soon.

---------------------------------------------------------------------------------------------------------------------Collaborator Acknowledgments

Tim Bates--RV Ron Brown R. Zhang, Beijing; Jun Xu and R. Wu, Hefei, PR China Mikio Kasahara (and group)--Kyoto/Tango/Mt. Heie, Japan Young J. Kim-Kwangju and Cheju; Ki-Hyun Kim, Jianzhen Yu-Kosan; Prof. Kang--1100 m Cheju, Korea George Lin Taiwan Russ Schnell--Mauna Loa Observatory Catherine F. Cahill--Adak Island/Poker Flat, Alaska National Park Service--Crater Lake, Oregon Funding National Science Foundation, with help from National Oceanic and Atmospheric Administration and National Park Service IMPROVE (samplers).

For information on other DELTA Group projects, please contact us.