James P. Lodge

Atmospheric Gases and Particulates in Panama

The concentrations of trace gases in tropical air from samples taken on the Isthmus of Panama are compared with those reported by others. The role of a tropical land mass as a sink or source of atmospheric components is discussed.

Antarctic Atmospheric Chemistry: Preliminary Exploration

The particulate and trace gas content of polar air is very similar to that of tropical air despite diflerences in climatology and biotic activity. biologic particulates and moisture.

Measurements of atmospheric pollutants in the St. Louis area

Abstract Measurements of the concentrations of trace gases and particles have been made in the plume from metropolitan St. Louis at 80 and 120 km from the urban center. The concentrations of SO2, NO2, NO, NH3, H2S, aldehydes, CO, total hydrocarbons, and CFCl3 were determined. The concentrations of many of these gases were found to be significantly higher in the plume than outside the plume at these distances. Measurements were made near the ground and from an aircraft. The width of the plume was usually between 20° and 30°, which is less than had been expected. By comparing the concentrations measured at 80 km from the city with those measured at 120 km from the city, and using the decrease of conservative trace gases to account for loss through physical process, we have arrived at preliminary estimates of the decay rates for a few trace gases. The evidence is most compelling for sulfur dioxide, and it appears that, at ca. 100 km from the city, the overall half-life of SO2 is between 2 and 8 h.

The Sampling and Electron Microscopy of Asbestos Aerosol in Ambient Air By Means of Nuclepore Filters

Despite the fact that adverse health effects of asbestos have been known since shortly after the turn of the century,1 there has been little progress in techniques for determining the mineral in the airborne state. This absence of sampling and analysis methods appears to derive from two main sources: (1) In the environments of the asbestos using industries, asbestos concentrations tend to be high relative to other particulate species, and especially compared with other fibrous species, making estimation of concentration by microscopy relatively easy. (2) The term asbestos describes a crystal habit, not a chemical compound; therefore there is no unique chemical property of asbestos that can be used as the basis for its measurement. Interestingly, there appears to be no basis for distinguishing the health effects of one type of asbestos over another;2 the physiological response seems more dependent on crystal habit than on composition.

Interpretation of selected EPA field data on particulate matter samplers: Rubidoux and Phoenix II

An analysis has been performed of data on particle samplers obtained during 1984 at Rubidoux, California, and Phoenix, Arizona, by the US EPA, with emphasis on prediction of mass collected by the Andersen model 321A and Wedding inlet (previously GMW40CFM) PM/sub 10/ samplers. Recent interpretation of these data appears to fail to correct adequately for particle bounce, and to severely overestimate the FINE particle mass. The present study uses two completely different algorithms to make these corrections. The results obtained from these two approaches agree within a few percent, and lead to a prediction of the mass collected by the Wedding inlet within 7 percent. The Andersen 321A sampler, on the other hand, overcollects by as much as 34 percent. This analysis, if substantiated, would raise serious questions concerning the adequacy of the presently proposed Federal Reference Method for qualification of PM/sub 10/ samplers.

Chemical (Atmospheric) and Biological Measurements in Panama. Volume 1. General

The report series (Vol. I) presents the chemical measurements made by the Atmospheric Chemistry Group of the National Center for Atmospheric Research (NCAR) for the project, Trace Chemistry of Tropical Atmospheres, supported in part by the Army Research Office (ARO), Durham, N.C. (contract DAHCO4 67-COO24). The study was conducted from February 1965 to January 1970, while the Atmospheric Chemistry Group was part of the NCAR Laboratory of Atmospheric Science. The report series also includes the chemical and biological measurements made by the U.S. Army Tropic Test Center (USATTC) for the project. Volume I of the report series describes the project and the 34 sampling sites used for chemical and biological sampling (most of which are in the Canal Zone).

Rack for Square Cuvettes

For many spectrophotomemc determinations, it is convenient to use a reasonably large number of cuvettes, rather than rinsing after each determination. When the color reaction used is time dependent, or when the samples are such that a dry cuvette is needed, a number of cuvettes are required. In such a case, additional spectrophotometer cuvette holders are usually obtained to hold the samples. Since these are not intended to use as cuvette racks, they tend to be expensive, corrodible, and hkely to spill.