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Health Effects Task Force Local Studies: 1995-2011
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We have completed work on ten local studies on air pollution in collaboration with UC Davis, California Air Resources Board (CARB), Kaiser Permanente, California Department of Health Services, California Office of Environmental Health Hazard Assessment and others, with funding from and in collaboration with the Sacramento Metropolitan Air Quality Management District.  In 2010 and 2011, three of these studies were accepted for publishing by the American Association of Aerosol Research (AAAR) in their journal, Aerosol Science and Technology (AS&T).

Health Effects Task Force Studies

April 2011 study in collaboration with Thomas A. Cahill, PhD, and Richard A. VanCuren, PhD, UC Davis Delta Group:
Wood Smoke Study at SMAQMD Del Paso Manor Monitoring Site

The 2009-2010 Del Paso Manor Winter PM2.5 study was conceived to demonstrate the utility of extremely high temporal and compositional resolution sampling as a means to unravel the various source contributions to elevated 24-hour PM2.5 concentrations.  The study demonstrated successful collection of samples with limited staff time invested at the sampling site, and a successful analytical program that has produced findings that are both scientifically novel and applicable to the needs of the SMAQMD.

The large data set, over 64,000 individual values in the 12 day intensive period around Christmas and New Year, lent itself to a statistical analysis.  A 9-component factor analysis technique was applied to the entire data set of gases and aerosols, as a function of particle size and composition.  This analysis was able to separate the contribution of finer ‘brake/tire dust’ from local road dust, showing that ‘brake/tire dust’ roughly matched the pattern of the Christmas period mass exceedances.  

A significant finding from this analysis was that the highest peak PM2.5 concentration during the study, occurring over the Christmas holiday, was driven by unusually fresh emissions from residential wood combustion, and, based on its temporal pattern, not primarily for heat.  It seems likely from these data that the SMAQMD program to control burning wood through a public information program based on meteorology has been successful, and that the unique events of Christmas 2009 were due to atypical behavior by residents who engage in infrequent burning for social reasons. 

Please click here to view the full text of the Del Paso Manor Wood Smoke Study.


January 2010 study in collaboration with Thomas A. Cahill, PhD, and David E. Barnes, UC Davis Delta Group:
Particulate Air Pollution and the Excess Mortality from Ischemic Heart Disease in  the California Central Valley; What are the Causes?

Using the UC Davis Rotating Drum Impactor (8 DRUM), this study confirmed the finding of our 1998 study on IHD mortality rates (see summary below), while providing much more complete data to isolate the causal factors in the death rate from IHD.  Data collected at five sites along the Central Valley over a one month period were compared to current mortality rates and confirmed that only fine and ultra fine particulates correlated with increased mortality rates.  This study generated a large body of original data suitable for medical impact analysis, offering a new option for better tying aerosols to health.

May 2009 study in collaboration with Thomas A. Cahill, PhD and David E. Barnes, UC Davis DELTA Group:
Comparison of Fine Mass, UC Davis DRUM versus FRM, at the ARB 13th and T Street Site

This one year side by side monitoring study, sanctioned by the California Air Resources Board at its 13th and T Street site, compares mass data collected by the U C Davis rotating drum impactor (8 DRUM) with ARB’s standard mass monitoring measurements.  The study showed that the 8 DRUM monitor proved to be a cost effective way to obtain important additional data for health and regulatory needs while being accurately comparable to the ARB’s mass measurements currently required by law.  In particular, this study introduces vital new information about ultrafine particulate matter which studies now show is capable of deep lung deposition, and heart and brain impacts.

April 2008 study in collaboration with Thomas A. Cahill, PhD, UC Davis:
Removal Rates of Particulate Matter onto Vegetation as a Function of Particle Size

Conducted at the University of California, Davis, this wind tunnel study showed that all forms of evergreen vegetation were able to remove 30% to 80% of very fine particles at wind velocities below roughly two miles per hour during the 2 to 4 seconds in which the particles were within the vegetation chamber. Redwood and deodar were about twice as effective as live oak. The success of this study has led to one to begin January 2009 that will compare protective qualities of evergreen vegetation downwind and adjacent to Highway I-5 in Sacramento as compared to unprotected sites also downwind of I-5. Click here to read a one page summary of the report.

2007 study in collaboration with Thomas A. Cahill, PhD, UC Davis and T.M Cahill, ASU:
Air Quality at Roseville Railyard Poses Cancer Risk : Recent Study by Health Effects Task Force Also Outlines Multiple Solutions

This study was conducted in collaboration with the Placer County Air Pollution Control District (PCAPCD) and its Roseville Railyard Aerosol Monitoring Project (RRAMP). The study report consists of seven components all of which bear on monitoring emissions from the Railyard in Roseville. Some components were funded by EPA Region IX in a grant to PCAPCD and some were collected by Dr. Cahill as a volunteer with Breathe California of Sacramento-Emigrant Trails (BCSET) and the Health Effects Task Force (HETF). This study is the first of its kind to analyze the chemical content of the highly toxic ultrafine particulates in locomotive diesel at the railyard. A key study finding revealed that the locomotive diesel exhaust from the Roseville Railyard is about 5.5.times richer in the most carcinogenic components of diesel exhaust (benzo[a]pyrene, among others) than is the exhaust from diesel trucks. A chapter of this report is dedicated to recommendations for mitigation of emissions at the Roseville Railyard.

2006 study in collaboration with Thomas A. Cahill, PhD, UC Davis:
Vehicular Particulate Exposures and Potential Mitigations Downwind of Watt Avenue, Sacramento, California

This third and final phase of a series of studies conducted by Dr. Cahill for Breathe California of Sacramento-Emigrant Trails focused on air quality impacts from traffic on Watt Avenue which confirmed previous findings that very fine and ultrafine particulates substantially impacted Arden Middle School immediately downwind of Watt Avenue at Arden Way. A new section in this report addresses mitigation opportunities for those who reside downwind of heavily trafficked urban corridors such as Watt Avenue. This report also emphasizes that although the California Air Resources Board has declared diesel particulates toxic to human health (California Almanac 2006), no health protection standards have been established by the California Air Resources Board or the Environmental Protection Agency for the very fine and ultrafine particulates found in diesel exhaust. This study received guidance and support from Arden Middle School and San Juan Unified School District personnel and county departments.

2005 study in collaboration with Thomas A. Cahill, PhD, UC Davis:
Sacramento/Interstate 5 Transect Study, Phase II, Winter Months

This second phase examined the impacts of secondary roadways carrying predominantly car traffic. On Watt Avenue, diesel trucks, although they represented only about 1.5 percent of all vehicles, contributed about 1/3 of all the very fine and ultrafine particulates, while cars contributed 2/3 of the very fine and ultrafine particulates, which substantially impacted Arden Middle School.

2003 study in collaboration with Thomas A. Cahill, PhD, UC Davis:
Sacramento/Interstate 5 Aerosol Transect Study

This study measured air pollution levels at nine sites upwind and downwind of Highway I-5 and east to the foothills. The level of diesel/smoking gasoline vehicle impacts was larger at Arden Middle School directly downwind of Watt Avenue than at the Crocker Art Museum directly downwind of Highway I-5, despite lower traffic flows on Watt Avenue. Very fine particulates traveled well away from freeways and filled large areas of downtown Sacramento.

2003 study in collaboration with the California Air Resources Board:
Short Term Study of Outdoor Air Quality at Two Sacramento Schools on Watt Avenue

This limited study provided some insight into the air quality of the two schools, Arden Middle School and Frederick C. Joyce Elementary, but showed that the overall Sacramento region had a stronger influence over the air quality of the schools than the local sources of air pollution. Diesel particulate was not measured as part of this study because no methods to measure diesel particulate were available to CARB at the time the study was conducted.

2003 study in collaboration with Michael Lipsett, MD, OEHHA on MediCal youth with asthma in the Sacramento Region:
Air Pollution and Exacerbation of Pediatric Asthma in Sacramento

Specific to the Sacramento Region, this study demonstrated a link between SMOG and childhood asthma attacks resulting in hospitalizations and emergency room visits. This study has not been released for publication.

2002 study in collaboration with Steve Van Den Eeden, PhD, Kaiser Permanente:
Particulate Air Pollution and Morbidity in the California Central Valley

This study found strong and consistent air pollution effects between particulate matter and acute and chronic respiratory hospitalizations among Kaiser Permanente members, 60 percent of whom lived in the Sacramento Region.

1998 study in collaboration with Thomas A.Cahill, PhD, UC Davis:
Comparison of Cardiac and Stroke Mortality to Carbon Monoxide, Ozone, and Particulate Air Pollution Concentrations in the Sacramento Valley Region

This study compared CA Dept. of Health Services mortality data to CARB air pollution data, suggesting a statistically strong link between PM 10 and increased mortality from ischemic heart disease, with weaker evidence for heart attacks and strokes and ozone air pollution.

For more information regarding these studies or the Health Effects Task Force, please contact Betty Turner at (916) 444-5900 ext. 214 or

The Health Effects Task Force and its studies are supported by the Sacramento Metropolitan Air Quality Management District.

Health Effects Task Force

The Health Effects Task Force (HETF) is a group of air quality and health experts who for over 15 years have volunteered to leverage their skills and expertise to further locally based studies on the health impacts of air pollution in Sacramento and the Central Valley of California. This is an area with known and serious air pollution problems that differ significantly in type from other extensively studied areas in California and the nation.

The HETF has been chaired since its inception by Jananne Sharpless, former chairwoman of the California Air Resources Board, with members drawn from organizations such as the Cal EPA/ARB, Kaiser Permanente, California Office of Environmental Health Hazard Assessment, University of California, Davis, Sacramento County Health Department, and local research companies, among others.

Local air districts have funded the work of HETF with modest grants for over ten years with results only achievable because of the dedication of this extraordinary group of volunteers.

Eight studies specific to this region have been completed identifying:

  • How strategically placed vegetation downwind of busy roadways can remove ultrafine particulates from the air, thereby protecting the health of residents,
  • Effects of air pollution on mortality rates from ischemic heart disease and stroke in the Central Valley,
  • Particulate air pollution and rate of hospitalizations;
  • Increased hospitalizations and emergency room visits of MediCal youth with asthma during high ozone days; and
  • Three studies on exposure to ultrafine particulates across Sacramento and at a school site directly downwind of a densely trafficked urban corridor.

Other studies in progress include a ten year study looking at air pollution effects on the elderly; a study on the health protection effect of vegetation and downwind barriers on very fine and ultrafine particulates from freeways; and a one year comparative study of data captured by the Cahill 8 drum sampler and the California Air Resources Board monitor at the 13th and T Streets site in Sacramento.


Members of the Health Effects Task Force

Jananne Sharpless, Chair
Former Chairperson
California Air Resources Board; Former Member
California Energy Commission

Tom Cahill, PhD
Director, Delta Group, Land, Air & Water Resources

Linda Davis-Alldritt, RN,MA,PHN,FNASN
School Nurse Consultant, Ca., Dept. of Education

Larry Greene, Ex Officio Member
Executive Director, Air Pollution Control Officer

Farla Kaufman, PhD
Reproductive & Cancer Hazard Assessment, Branch Ofc.of Environmental Health Hazard Assessment

Michael Lipsett, M.D., Chief
CA Dept. of Public Health, Env. Health Investigations Branch

Helene Margolis, PhD, MA
Assistant Adjunct Professor of Medicine, Dept. Internal Medicine: General Medicine & UCD, Center for Health Care Policy and Research
School of Medicine, Univ. of California, Davis

Charles Plopper, PhD, DVM
Professor Emeritus, Dept. VM Anatomy, Physiology & Cell Biology, Univ. of California, Davis

Ralph Propper, MS, MPH
Air Pollution Research Specialist, Air Quality & Climate Science Section, California Air Resources Board

Glennah Trochet, M.D.
Former Sacramento County Public Health Officer , County of Sacramento

Richard A. Vancuren, PhD
Delta Group, Air, Land & Water Resources, UC Davis

Dane Westerdahl, D.Env.
Assistant Professor, Sibley School of Mechanical And Aerospace Engineering, Cornell University

Earl Withycombe, PE
Air Resources Engineer, California Air Resources Board

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