Measurement of the concentration of sulfur dioxide, nitrogen oxides, and ozone in the National Archives Building

Abstract

The figures consist of five figures that are plots of the concentration of oxides of nitrogen measured at different locations. These begin on page 15. .

The characterization of microenvironments and the degradation of archival records :

“…This is, of course, not the case. The concentration of pollutants in the stack atmosphere is known to fluctuate (2) and, in the case of , to follow the diurnal variations in the ambient District of Columbia environment (2). Hence, in this section we answer the question, "What happens when the exterior concentration is not constant?"…”

“…Certainly it is known that the cellulose molecule is oxidized by N 2 O 4 to form primarily a carboxyl at the C -6 position and secondarily aldehyde and ketone groups at other positions in the molecule (42) Other polymers are known to undergo chain scission by NOj (43,44), but the only work that we have found that relates to the degradation of paper is a study of the degradation of cotton fabric (45) In this work, cotton fabric was exposed at room temperature and normal humidity to atmospheres separately containing various concentrations of NO 2 …”

“…Ozone concentrations in the National Archives Building, at least in winter, are at undetectably low levels (2). Their summer levels are unknown, but data from libraries and museioms in other places imply that they might be high (4,p.20).…”

“…For that purpose we consider that the concentration of pollutant in the stacks varies in the manner of NO^as determined by Hughes and Myers (2) We further simplify this by assuming a sinusoidal variation with a period of twelve hours. A sketch of the assumed variation is shown in Fig.…”

“…Because the temperature and the condition of the atmosphere in the storage areas are important in controlling the rate of degradation of the stored records, these areas (the "stacks") have temperature and humidity control. However, atmospheric pollutants such as particulate matter, NO^^, SO 2 and ozone cause degradation of records, (see, e.g. reference (1)), and while in some cases the removal of air pollutants from the external air by the NARA air conditioning system is efficient, in other cases it is not (2), with the result that the concentrations of S 02 ,and NO^^in the stack atmosphere are above recommended levels (3,4).…”