Review of the Air Quality Criteria Document for Particulate Matter

More documents

Recommendations

Info

same tidal volume of 500 mL at 15 breaths/min, and this means for women, generally smallerthan men, an increased minute ventilation compared to their normal breathing condition.Therefore, gender-related differences in deposition found here may be due to the fact thatwomen breathed at a relative larger minute ventilation and would not show if both men andwomen would breath at their normal size-adjusted tidal volumes. A critical discussion along thisline should be added.Line 13: It would be helpful to add here a summarizing paragraph since thereviewed studies on gender differences show somewhat differing results and it would beappropriate to have a summarizing concluding statement.Page 7-20, lines 1-2: When comparing deposition efficiencies in the lungs of childrenvs. adults, it should also be considered that children have a higher minute ventilation per unitbody weight compared to adults.Line 26: Again, a summarizing paragraph would be helpful regarding age-relateddeposition differences.Page 7-25, line 17: ">5 µm" should be "
efficiencies as well as the ratio of rat to human lung surface areas. This paragraph needs to berevised.Page 7-29, lines 1 and 2: This concluding sentence stating that deposition density shouldbe considered when extrapolating health effects seen in rodent studies to the human situationneeds to be expanded in that other factors should be considered as well, such as dose in thespecific region, dose per unit surface area, dose per cell (e.g., alveolar macrophage), and alsoparticle parameters such as solubility, volume, surface area, size. Although deposition density isvery important, other factors should not be neglected.In this section on interspecies differences, it would also be useful to mention theavailability of the Multiple Path Particle Deposition model (MPPDep) which allows thecalculation of particle deposition in human and rat respiratory tracts assuming different exposurescenarios and breathing patterns and particle parameters.In general, in this section on particle deposition efficiencies in the human respiratorytract and in the rat, a figure would be useful so the reader would not have to consult otherpublications for this purpose.Page 7-31, Figure 7-3: If the size of the arrows in this figure indicates major vs. minorclearance pathways, then the arrow from phagocytosis by alveolar macrophages to passagethrough alveolar epithelium should clearly be a minor arrow since only a tiny fractionphagocytosed by macrophages takes this route (studies by Harmsen et al.), and the existence ofthis route might even be questioned. However, under particle overload conditions thetranslocation to interstitial sites via endocytosis by type I and type II alveolar cells becomes amajor pathway, but this does not occur via particle-laden alveolar macrophages.The meaning of the double-headed arrow from pulmonary capillary endothelium tophagocytosis by interstitial macrophages is not clear, does it mean that particles or interstitialmacrophages with particles are coming back from the endothelium? Also, the arrow fromphagocytosis by interstitial macrophages to pulmonary capillary endothelium is not clear: Isthere compelling evidence that, indeed, interstitial macrophages with phagocytized particles areentering the pulmonary capillary endothelium?Page 7-32, line 3: Not all solutes will be absorbed rapidly, it depends on the rate ofdissolution from a particle as well as on the molecular size of the solute and other parameters tobe discussed later.Line 10: Probably meant here is that particles re-enter the airway lumen frommucosal sites, is there any reference for that?Line 23 and 27: I don't think that the general statement can be made that the"magnitude of any increase in cell number (alveolar macrophages) is related to the number ofdeposited particles rather than to total deposition by weight". This would result in a hugeincrease in the case of deposition of ultrafine particles. Furthermore, cytotoxicity of a givenparticle is certainly a big stimulus for inflammatory cell increase, and if particles are soluble thenthe mass and not the number is the major determinant for eliciting cells. A better dosemetric torelate cellular responses to deposited poorly soluble particles would be particle surface area, andthere are a number of studies which demonstrated that specifically for ultrafine and fine particles- given that they are not chemically different - particle surface area correlates very well with theincrease in inflammatory cell numbers. Again, that applies only to poorly soluble particles andnot for soluble ones where mass is the more appropriate dosemetric.Page 7-32, line 31: This describes the pathway in Figure 7-3 of macrophages traversingthe alveolar capillary endothelium directly entering the blood stream. Again, has this beendemonstrated for macrophages with phagocytized particles?Page 7-33, lines 1-11: There are a number of statements in this paragraph which need tobe supported by appropriate references. For example, what is the evidence for macrophages withphagocytized particles traveling to extrapulmonary organs? Are these new data? What is theevidence of particles binding to macromolecules?Lines 17-29: The clearance of solutes is a bit superficially treated here, it is notthat simple. It depends on the lipophilicity vs. hydrophilicity of solutes and the molecularweight. There are also different solubilities depending on the intra- vs. extra-cellular localizationA - 66
Page 5:
known, the potential causes deserve
Page 10:
SCIENCE ADVISORY BOARD STAFFMr. A.
Page 13 and 14:
Page 2-77, line 19-22: Should menti
Page 15 and 16:
Page 8-1, lines 26-28: Combustion a
Page 17 and 18:
mode vs. the other. In fact, such k
Page 19 and 20:
p. 7-49, l. 20 In an effort to make
Page 21 and 22:
ambient PM effects. The paragraph d
Page 23 and 24:
dominant, one criticism is that “
Page 25 and 26: 6. Susceptible sub-populationsIt is
Page 27 and 28: is OK. But in most settings it stil
Page 29 and 30: 2. There are repetitions of the sam
Page 31 and 32: 15. Page 3-57 and 3-58, line 29-31
Page 33 and 34: P 7- 27, L 15: What does “compara
Page 35 and 36: there is pertains almost solely to
Page 37 and 38: studies, and is presented as observ
Page 39 and 40: P 8-47, L 23-27: These two sentence
Page 41 and 42: also be summarized. Second, the cha
Page 43 and 44: P 9-76, L 30: It should be “these
Page 45 and 46: 4. Page 4-7,lines 14-18. Similar th
Page 47 and 48: control when it may be possible to
Page 49 and 50: 1990. Reference Lioy, P.J. “The A
Page 51 and 52: document.P. 5-82, Lines 15-30 Need
Page 53 and 54: 7-12 8 insert "that are either very
Page 55 and 56: 8-62 10,11 The preceding discussion
Page 57 and 58: 9-27 17 insert "source and/or" afte
Page 59 and 60: 2. The paper by Künzli et al. on t
Page 61 and 62: 6-243 12 This section (6.4.4.) shou
Page 63 and 64: Chapter 5. Human Exposure to PM and
Page 65 and 66: the chapter. Many of the poor quali
Page 67 and 68: Page 5-17, equation 5-10; the coeff
Page 69 and 70: illustrated using a figure from Kel
Page 71 and 72: tied back to the base-line health s
Page 73 and 74: Page 7-4, Structure of the Respirat
Page 75: Günter Oberdörster, PhDChapter 7
Page 79 and 80: The title of this section is also s
Page 81 and 82: old and young rats and mice used on
Page 83 and 84: passive use values as opposed to us
Page 85 and 86: Specific Comments:Page 5-19, lines
Page 87 and 88: Chapter 9 - General CommentsThis ch
Page 89 and 90: George Taylor, PhDAir Quality Crite
Page 91 and 92: atmospheric stressors associated wi
Page 93 and 94: “At the surface, a variable fract
Page 95 and 96: that point from this review! “Vis
Page 97 and 98: 6. P 2-86, section 2.2.5.1 - A shor
show all

Review of the Air Quality Criteria Document for Particulate Matter

Create successful ePaper yourself

Delete template?

Save as template?