Health Assessment Document for Diesel Emissions - NSCEP | US ...

CONTENTS (continued)
2.5.1. Volatile Organic Compounds Attributable to Traffic .................. 2-47
2.5.2. Polycyclic Aromatic Hydrocarbons ..... ·.· ........................ 2-47
2.5.3. Nitroarene Concentrations in Ambient Air .......................... 2-51
2.6. EXPOSURE PERSPECTIVE .......................................... 2-56
2.7. SUMMARY ....................................................... 2-58
2.8. REFERENCES ................................................... · .. 2-59
4. DOSIMETRIC FACTORS .................................................. 4·1
4.1. INTRODUCTION ........ ' ....................... : . .................. 4-1
4.2. REGIONAL DEPOSITION OF INHALED PARTICLES .................... 4-2
4.2.1. Physical Processes, Physiological/ Anatomical Considerations,
and Particle Characteristics ....................................... 4-2
4.2.2. Species Variability in Regional Dose ............................... 4-4
4.3. RESPIRATORY TRACT CLEARANCE RATES .......................... 4-6
4.3.1. Tracheobronchial Clearance ...................................... 4-6
4.3.2. Clearance From the Alveolar Region ............................... 4·9
4.3.2.1. Alveolar Clearance in Humans ............................. 4-9
4.3.2.2. Alveolar Clearance in Animals ............................ 4-10
4.3.2.3. Lung .. Burden and Pulmonary Overload Resulting in·
Impaired Clearance ..................................... 4-13
4.3.3. Role of AMs in the Clearance of Particulate Matter ................... 4·16
4.3.3.1. AM-Mediated Clearance of Particulate Matter ................ 4-16
4.3.3.2. Translocations ofParticles to Extraalveolar
Macrophage Compartment Sites ............... .' ........... 4-18.
4.3.3.3. Potential Mecharusms for an AM Sequestration
Compartmentfor Particles During. Particle Overload ........... 4-20
4.3.3.4. Physiologically Based Models for Pulmonary
Retention and Clearance oflnsoluble Particles ................ 4-21
4.4. BIOA V AILABILITY OF ORGANIC CONSTITUENTS PRESENT
ON DIESEL EXHAUST PARTICLES ............................... : .. 4-22
4A.l. Laboratory Animal Studies ...................................... 4-23
4..4.2. Extraction of Diesel Particle-Associated Organics in
Biological Fluids . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.:25
4.4.3. Extraction of Diesel Particle-Associated Organics by
Alveolar Lung Cells and Other Cell Types ................ : ......... · 4-27
4.4.4. Bioavailability of Adsorbed Compounds as a Function of Particle
Clearance Rates and Extraction Rates of Adsorbed Compounds .. : ...... 4·28
4.5. CONSIDERATIONS FOR DOSIMETRY MODELING .................... 4-30
4.6. SUMMARY ........................................................ 4-31
4.7. REFERENCES ...................................................... 4·33
5. NONCANCER HEALTH EFFECTS OF DIESEL EXHAUST . . . . . . . . . . . . . . . . . . . . 5-1
5 .1. HEALTH EFFECTS OF WHOLE EXHAUST . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-1 ·
211/9.8 lV DRAFT--DO NOT CITE OR QUOTE