Review of the Air Quality Criteria Document for Particulate Matter

“At the surface, a variable fraction of the solar radiation is reflected back upwards, referred to assurface reflectance or the albedo, illuminating the atmosphere from above and below.” (P 4-88,L 4)“The increase was largest in the summer and decreased in the winter.” (P 4-108, L 28)“Some of the visibility impairment in northern California and Nevada, including Oregon,southern Idaho and western Wyoming, ...” (P 4-109, L 16)“Horvath (1993) reported that measured light absorption efficiencies for light absorbing carbonranges from 3.8 to 17 m 2 /g. According to Horvath (1993), calculated absorption efficiencies aretoo high, ranging from 8 to 12 m 2 /g for monodispersed carbon particles.” (P 4-90, L 12)“For most rural eastern sites, sulfates accounts for >60% of the annual average light extinctionon the best days ..” (P4-108, L 23)“However, several sites are not showing steady improvements in either visibility or PM 2.5 ,particularly in the number of worst visibility days (90 th percentile).” (P 4-111, L 20) [In otherwords, the number of days in a year is holding steady at about 365 per.]There are tautologies and circular definitions of the sort associated with Lewis Carroll:“Human vision is one of the factors that affects the way an object is viewed.” (P 4-86, L 10)“Discoloration may be used as a quantitative measurement of atmospheric color changes inurban hazes.” (P 4-98, L 2) [In much the same way as morbidity can be used as an indicator ofimpaired health.]“The light-extinction coefficient is the quantitative measure of haziness, defined as σ ext =K/visual range, where K is the Koschmieder constant. The value of K is determined both by thethreshold sensitivity of the human eye and the initial contrast of the visible object against thehorizon sky. The visual range may be calculated from the light-extinction coefficient using theKoschmieder equation ..” (P 4-94, L 23)There is simple technical ignorance:“The cones, a receptor cell in the retina, govern visibility interpretations.” (P 4-86, L12) [Thisis why an eyeball can be offended by haze even after surgical removal from the head. And whywe see nothing after sundown.]“Some of the light in the sight path is absorbed or scattered towards the observer. The remaininglight is absorbed or scattered in other directions.” (P4-86, L 24) [Leaving the observersearching in vain for any transmitted image.]“The scattering and absorption efficiencies are determined by estimating the size distribution ofeach particle.” (P 4-89, L 20)“.. the extinction coefficient that is calculated from the visual range, corrected to 60% relativehumidity by the Koschmeider relationship.” (P 4-109, L 29) [Versatile guy, that K.]“Mie scattering is the scattering of all visible wavelengths equally (Shodor EducationFoundation, Inc., 1996).” (P 4-87, L 1) [Which must be why Mie theory is computationally sotrivial. Distressingly, this claim is supported by the citation, which turns out to be on-linetraining material developed for the Agency. The cited page also explains “how the shorterwavelengths which our eyes detect as blue when mixed, are scattered at a right angle. If the sunA - 82