Herbert C. McKee

Atmospheric Ozone in Northern Greenland

The concentration and daily variations in ozone concentration at ground level in Northern Greenland were measured. A correlation was found between sunlight and ozone concentration. This correlation, coupled with the knowledge of air-moss movements in the region, provides excellent evidence that the ozone being measured was formed continuously in the atmosphere and was not brought to the area by some transport mechanism. The results also indicate that ozone is a transient intermediate in the atmosphere and that it decomposes as fast as it forms.

Automobile exhaust particulates - source and variation

Automobile exhaust particulates amount to approximately 5% by weight of the amount of gaseous hydrocarbon emission, and consist of lead compounds, carbon particles, motor oil, and non-volatile reaction products formed from motor oil. The total amount of exhaust particulate emitted from automobiles is much less than the amount of hydrocarbon vapor emitted, and therefore, from an overall viewpoint, is less important as a primary pollutant. Particulates might influence the course of gas-phase atmospheric reactions through catalytic or other effects.

Comparison of various sources of automotive emissions

All normal sources of hydrocarbon emissions from automobiles were investigated. Special emphasis was placed on crankcase fumes and carburetor evaporation losses since much less information is available concerning these emissions. Exhaust emissions were also measured in order to provide a basis for comparison. Consideration was also given to evaporation losses from the fuel tank of an automobile since this factor also has not been investigated in any detail. 4 references, 5 figure, 9 tables.

Collaborative Testing of Methods to Measure Air Pollutants, II. The Non-Dispersive Infrared Method for Carbon Monoxide.

The Methods Standardization Branch of the Environmental Protection Agency, National Environmental Research Center, has undertaken a program to standardize methods used in measuring air pollutants covered by the national primary and secondary air quality standards. This paper presents the results of a collaborative test of the method specified for carbon monoxide. The test involved analysis of CO in air samples (in cylinders) by participating laboratories. Three concentrations, covering the range of the method which is, 0 to 58 mg/m3, were analyzed dry and humidified on each of three days by 15 collaborators. The method of analysis, nondispersive infrared spectrometry (NDIR), involved an NDIR instrument in combination with different procedures for eliminating water vapor interference. A statistical analysis of the data obtained produced the following results: 1. The checking limit for duplicates (replication error) is 0.5 mg/m3. 2. The repeatability (variation within a laboratory) is 1.6 mg/m3. 3. The repr...

Use of Lead Sensitive Test Papers for Vehicle Inspections

Recent advances in vehicle emission control technology have reduced the effectiveness of the conventional tailpipe test used In inspection and maintenance programs. A different approach Is being followed in Harris County, Texas (Houston area), based on identification and correction of misfuellng and tampering. Misfueling Is being identified by using a lead-sensitive test paper to detect lead deposits in the tailpipe that result from using leaded gasoline. Field tests of this procedure demonstrated that it Is reliable and accurate for the Intended purpose. The data also indicated the need to observe certain precautions to avoid contamination and other potential sources of error. This procedure and other emission-related checks have been added to the annual safety inspections. These tests are conducted on vehicles of 1980 model year and later, by approximately 1150 Inspection stations throughout the county that conduct annual safety Inspections. Experience with the first few months of this program has been ...

The Problem of Equity in Emission Offsets

Potential inequities in the emission offset policy of the Environmental Protection Agency are discussed. It is shown that areas which had relatively strict pollution abatement programs before their baseline was set have relatively less potential reduction to allow for growth than areas which had less strict programs. This inequity could impose severe economic penalties on those areas which had aggressive pollution abatement programs prior to the Clean Air Act of 1977.

Texas Regulation Requires Control of Opacity Using Instrumental Measurements

For over four years, a Texas air pollution control regulation has been in force which permits use of a stack mounted transmissometer instrument to measure visible emissions, thus avoiding the necessity for visual observations. Many types of industrial plants have installed instruments, and extensive experience has been obtained with this method of measurement and control. Plant operators and enforcement officials have expressed a strong preference for this method, both to demonstrate compliance and to provide data to aid in operating control equipment. Some operational problems have been encountered, but these usually can be overcome with proper care. Because of the advantages obtained with this regulation a new regulation has been adopted which makes the instrumental method mandatory for large sources of visible emissions.

Estimation of Additive Effects from Multiple Sources

Using meteorological diffusion equations, a computer program has been developed to calculate the distribution of pollutants in an area affected by multiple sources, such as in a typical industrial district. Using rapid printout on a teletype terminal, data processing costs can be as low as two to three dollars for a printout showing distribution of pollutants over a distance of several miles and illustrating additive effects from multiple sources in the area. By integrating this method of data processing into a monitoring network and an emission inventory, the usefulness of monitoring data could be greatly increased to provide a much more realistic evaluation of ambient air quality within the area.

Instrumental Method Substitutes for Visual Estimation of Equivalent Opacity

Many air pollution control regulations limit the emission of visible effluents, based on the visual observation of “equivalent opacity.” Because of difficulties encountered in using visual observation, the Texas Air Control Board developed a method of calibration which made it possible to use an instrumental method for measuring visible emissions. A legal regulation based on this instrumental method has been in effect for almost two years. Despite minor difficulties in calibration and maintenance, results have been satisfactory. The use of the instrumental method avoids many of the difficulties inherent in using a regulation based on visual observation, and continued use of the instrumental method is anticipated.