The Bag Filterhouse for Oil-Fired Power Plants

This Report, published as Informative Report No. 7 of the Air Pollution Control Association’s TI-5 Public Utilities Committee, began to move through the 14 step approval procedure of APCA’s Technical Council in February 1964 Comments made by members of the Technical Council were considered in the preparation of the final report. It is now published as representing the best thinking of the Association. It is an extremely timely and informative report.     

APM-3 Recommended Standard Methods for Continuing Air Monitoring for Gaseous Contaminants

The purpose of Manual APM-3 is to provide a guide which will help increase the uniformity between various surveys, and thereby increase the useability of the data by others.     

Ozone Injury to Pinus Strobus

In a study of the ozone-induced needle blight of eastern white pine in central New York, acute injuries naturally induced on field trees during a year of relatively low ozone concentrations (1 966) were compared with injuries induced during a year of higher concentrations (1967). Injuries were more frequent and severe and were associated with higher mean ozone concentrations in 1967 than in 1966. Characteristic symptoms were induced on foliage of pine branches exposed to controlled doses of ozone as low as 7 ± 1 pphm for four hours or 3 ± 1 pphm for 48 hours. Such doses were equalled or exceeded two and four times, respectively, in the field during the 1 967 season. Ozone sensitivity of pine needle tissue was increased by fumigation in atmospheres containing water mist. High concentrations of ozone (40-60 pphm) caused general injury of foliage of both ozone-susceptible and resistant trees; the symptoms were unlike those found in the field or caused by fumigation with low concentrations of ozone.     

New PbO2, Support for the Measurement of Sulfation

Since 1966, the Division of Laboratories of the Department of Health of the City of Montreal is carrying on measurements of gaseous pollutants. In order to efficiently use the technical staff that our administrators wanted to devote to the fight against air pollution, a new lead dioxide support for the determination of sulfur dioxide has been devised. The preparation of candies according to the standard method requires much time and skill from the operator, whereas the technique that is proposed is rapid, easy, and provides plates of a high degree of uniformity. A technician with little experience can coat a great number of plates per day with no difficulty. N. A. Huey working at the National Center for Air Pollution Control in Cincinnati published in the September 1968 issue of this Journal a new technique which consists of coating the inside of a plastic Petri dish with a PbO² paste. His method also has the above mentioned advantages. The plates that are suggested allow a simplification of the preliminary work for several types of analyses such as gra-vimetry,¹ colorimetry,³ turbidimetry,^4,5 titrimetry,⁶ and nephelemetry.⁸     

Author’s Reply

A technique is developed to compute precision requirements for component parts of an emissions inventory to ensure (at a given confidence level) an overall acceptable precision in the estimate of total emissions. Since the emissions inventory is a basic requirement of air quality control implementation plans and provides a valuable management tool for planning air pollution control activities, it isi appropriate to state in quantitative terms the confidence that can be associated with each inventory. The approach reported here uses weighted sensitivity analysis methods to distribute both percentage and physical errors in source class emissions according to their contribution to the total emissions, and utilizes Chebyshev’s inequality to establish confidence levels for total emissions. The analysis has been extended to cover the case where one or more of the error components in a given inventory source class can be fixed by the analyst. The utility of the technique is manifold and several practical applications are reported. In particular, it serves to establish percentage error requirements for source categories to satisfy given error bounds for the overall emissions inventory at a given level of statistical confidence. The weighted sensitivity analysis technique possesses a high degree of generality, being applicable to compute component error requirements for any kind of data inventory which exhibits a hierarchical (tree-like) structure, as exemplified by NEDS Emissions Summary Reports. This work should be of interest to air pollution control planners at all levels of government and to anyone responsible for the air pollution portion of environmental impact statements.     

Cyclic Trends in Los Angeles Fine Participates

Noontime visibilities in downtown Los Angeles, averaged over the smog season of June through November, show two cycles of general deterioration and improvement. The improvement since 1962 is confirmed by available high volume filter data and conditions in 1974/75 are at least as good as at anytime since observations were begun in 1933. The decrease in frequency of “rule 57” days suggests that the improvement of the last decade and perhaps the cyclic variation of the past 40 years has been primarily of meteorological origin.