2009 Progress Report: Project 5 -- Architecture Development and Particle Deposition

EPA Grant Number: R832414C005
Subproject: this is subproject number 005 , established and managed by the Center Director under grant R832414
(EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).

Center: San Joaquin Valley Aerosol Health Effects Research Center (SAHERC)
Center Director: Wexler, Anthony S.
Title: Project 5 -- Architecture Development and Particle Deposition
Investigators: Wexler, Anthony S. , Plopper, Charles
Institution: University of California - Davis
EPA Project Officer: Chung, Serena
Project Period: October 1, 2005 through September 30, 2010 (Extended to September 30, 2011)
Project Period Covered by this Report: July 1, 2008 through June 30,2009
RFA: Particulate Matter Research Centers (2004) RFA Text |  Recipients Lists
Research Category: Health Effects , Air

Objective:

Objective of ResearchQuantify lung architecture, pulmonary function and particle deposition pattern changes due to pollutant exposure during development.

Progress Summary:

Progress Summary and Accomplishments: Three current activities are highlighted below: (1) lung architecture and function changes due to exposure diffusion flame particle (DFP) exposure during development, (2) lung architecture and function changes due to premixed flame particle (PFP) exposure during development, and (3) lung architecture and function changes due to ozone plus premixed flame particle (OPFP) exposure during development.
 
 
1 & 2. Lung architecture and function changes due to DFP or PFP exposure during development
The diffusion flame produced elemental carbon particles (DFP) with a concentration of 2.4x104 particles/cm3 in the exposure chamber and with a mean mobility particle diameter of 230.3 nm and a mass concentration of 71.73 µg/m3. The premixed φ=2.2 flames (PFP) produced 9.5x104 particles/cm3 with a mean mobility diameter of 72.7 nm and a mass concentration of 19.99 µg/m3, where φ is the equivalence ratio. To test the effects of PM exposure during lung development period, litters of male Sprague-Dawley rat pups housed with lactating mothers were placed in filtered air chambers at age one day. Exposure for six hours a day, five days a week for three weeks began when the pups were seven days old and ended at 25 days old. A matched set of pups was exposed to filtered air using the same protocol. At 28 days old, the animals were transferred from the exposure chambers to Bioclean hoods where they matured until necropsy at 80-81 days of age.
 
Body weights were similar between control group and exposed groups (p=0.641, 0.702 for DFP and PFP respectively). Lung volumes were also similar between control and DFP group (p= 0.195). The lung volumes in PFP exposed animals were significantly smaller than control group (small by 13.6% compared to control group, p=0.00014).
 
Figures 1-4 show the generation-averaged airway diameter, length, branching angle, and rotation angle. There were no significant differences in airway diameter and length between the control group and DFP exposure groups.

                                 (a)                                                                 (b)
Figure 1. Airway diameter as a function of generation number in the different groups (a) from generation 0 to 10, (b) from generation 11 to 22. * indicates p-value less than 0.05 and & indicates p-value less than 0.0022 (Bonferroni adjustment).
 
  
                                 (a)                                                                 (b)
Figure 2 . Airway length as a function of generation number in the different groups (a) from generation 0 to 10, (b) from generation 11 to 22.
 
 
 

 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

Both generation-averaged airway diameter and length for the PFP exposed group were consistently smaller than control. Diameter for PFP exposed animals was significantly smaller (p<0.05) than control in 9 of 23 generations and the differences were still significant in several distal generations after Bonferroni adjustment for multiple comparisons (Figure 1). For PFP exposure group, length also significantly decreased in 8 of 23 generations (Figure 2). Differences in the average diameter from control group were largest in the several proximal and distal generations and differences in the average length were largest in the distal generations.
 
 

 

                                 (a)                                                                 (b)
Figure 3. Branching angle as a function of generation number in different groups (a) from generation 0 to 10, (b) from generation 11 to 22.
 
 
                                 (a)                                                                 (b)
Figure 4. Rotation angle as a function of generation number in different groups (a) from generation 0 to 10, (b) from generation 11 to 22.
 
 
 

 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

PFP exposures elicited changes in branching and rotation angles between exposed and control groups. Branching angle decreased in most generations (Figure 3). Rotation angle also decreased in most generations and the differences from control group were significant in the middle generations (Figure 4). The changes in branching angle were statistically significant at generation 12 and for rotation angle at generation 11 even after Bonferroni adjustment (p<0.0022).
 
For lung function, resistance, compliance and TLC were evaluated using a forced oscillation technique. There was no significant difference in pulmonary function tests between control and exposed groups both DFP and PFP.
 
3. Lung architecture and function changes due to Ozone plus PFP exposure during development
 
Fewer geometric changes were elicited by co-exposure of ozone with PFP (OPFP). While the OPFP-exposed airway diameter was significantly smaller than control in several proximal generations, no significant changes were observed in distal generations. As was the PFP group, OPFP proximal airway diameters were appreciably smaller than control but change in distal airway diameter of OPFP was negligible compared to PFP. OPFP exposure slightly decreased the airway length in distal generations but the change was very small compared to PFP group. Co-exposure of ozone with PFP did not enhance the change in branching angle and rotation angle but rather weaken the effects of PFP. There were no significant change due to OPFP in all generations and no particular trend in relative differences compared to control group. These findings imply that lungs chronically exposed to ozone may become more resistant to oxidative stress and consequently mitigate the toxic effects of PM.
 

Future Activities:

We will analyze rat lungs exposed to metals (Fe), and compare them to normal lungs. Experiments of premixed particle exposure with different phi are currently underway. Supplemental ozone only exposures have been completed and data analyses are currently underway.  

Journal Articles:

No journal articles submitted with this report: View all 21 publications for this subproject

Supplemental Keywords:

RFA, Health, Scientific Discipline, PHYSICAL ASPECTS, Air, ENVIRONMENTAL MANAGEMENT, particulate matter, Environmental Chemistry, Health Risk Assessment, Risk Assessments, Biochemistry, Physical Processes, Risk Assessment, atmospheric particulate matter, children's health, particle deposition, acute cardiovascular effects, cardiopulmonary responses, chemical characteristics, human health effects, toxicology, airborne particulate matter, animal model, exposure, biological mechanisms, human exposure, PM, particulate matter components, exposure assessment, cardiovascular disease

Progress and Final Reports:

Original Abstract
  • 2006 Progress Report
  • 2007 Progress Report
  • 2008 Progress Report
  • 2010 Progress Report
  • Final Report

  • Main Center Abstract and Reports:

    R832414    San Joaquin Valley Aerosol Health Effects Research Center (SAHERC)

    Subprojects under this Center: (EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
    R832414C001 Project 1 -- Pulmonary Metabolic Response
    R832414C002 Endothelial Cell Responses to PM—In Vitro and In Vivo
    R832414C003 Project 3 -- Inhalation Exposure Assessment of San Joaquin Valley Aerosol
    R832414C004 Project 4 -- Transport and Fate Particles
    R832414C005 Project 5 -- Architecture Development and Particle Deposition