Page 61 - Copper and Bronze in Art: Corrosion, Colorants, Getty Museum Conservation, By David Scott

TABLE 1.2 TYPICAL MODERN CONCENTRATIONS OF ATMOSPHERIC CASES

NAME FORMULA CONCENTRATION
(ppb)
ozone O3 50-200
hydrogen peroxide H 2 0 2 10-30
nitrogen dioxide N0 2 10-45
nitric acid HNO3 1-10
hydrogen sulfide H 2S 0.1-0.5
carbonyl sulfide COS 0.5-0.6
sulfur dioxide s o 2 5-24
carbon dioxide c o 2 ( 3 - 6 ) χ io 5
formic acid HCOOH 0.2-1
acetic acid CH3COOH 0.2-1
oxalic acid (COOH) 2 not detected
formaldehyde HCHO 4-15
acetaldehyde CH3CHO 1-8
hydrogen chloride HCl 0.5-2

TABLE 1.3 CONVERSION FACTORS FOR CONCENTRATIONS OF SOME POLLUTANT
CASES IN PARTS PER BILLION (ppb) AND MICROCRAM/m 3 ( [ I Q / M ) 3

N A M E C O N V E R S I O N FA(: T O R
ppb to μ9/ιτι 3 μ9/ηι 3 to ppb

acetic acid 2.45 0.41
formic acid 1.88 0.53
acetaldehyde 1.80 0.56
formaldehyde 1.23 0.82
hydrogen sulfide 1.39 0.72
carbonyl sulfide 2.45 0.41
ammonia 0.70 1.44
sulfur dioxide 2.62 0.38
nitrogen dioxide 1.88 0.53
ozone 1.96 0.51

The general expression is microgram/m X conversion factor = ppb. All measurements are at standard
a 3
temperature and pressure, with temperature assumed to be 25 °C.