BACKGROUND/OBJECTIVE Much effort has been expended in attempting to document health effects attributable to atmospheric oxides of nitrogen. In connection with this effort@ the Chattanooga@ Tenn. region was selected for studies of nitrogen dioxide exposure where data correlations were to be made between observed health effects and air quality exposure. Nitrogen dioxide emissions from a trinitrotoluene (TNT) plant diffuse throughout the region creating varying exposure levels in different areas. A study of acute respiratory illness@ conducted from November 1968 to April 1969 among families residing in an area of relatively high NO- exposure@ in an area of elevated suspended particulate exposure@ and in two control areas in greater Chattanooga@ indicated consistently higher respiratory illness rates for all family segments in the high NO- exposure area than in the other areas where rates were average for the entire 24 weeks of study [1]. Significantly@ increased bronchitis morbidity was reported among elementary school children exposed for 2 and 3 years and infants exposed for 3 years to elevated levels of NO2 in ambient air [2]. A study conducted in 1970-71 of parents of senior high school students in the Chattanooga region showed a significantly lower forced expiratory volume for parents living in high NO2 exposure areas than for those living in low NO2 exposure areas and the control area [3]. The usefulness of results of previous studies and current projects depends to a large extent on the validity of air quality measurements obtained at sampling stations. Previous studies conducted in Chattanooga and elsewhere have been hampered by the absence of a reliable and accurate method for monitoring nitrogen dioxide in ambient air@ either continuously or as a batch sample. Recent investigations [4@ 5@ 6] have shown that the reference method (NASN modification of Jacobs-Hochheiser Method) possesses inherent deficiencies that raise questions as to the accuracy and validity of NO? data collected over the past decade and to the validity of the NO2 ambient air quality standard. The main objections to the reference method and the CHESS modification used in Chattanooga are the low and variable collection efficiency and the interference of nitric oxide on the measurement. To meet the need for further information about the effects of NO2on human health@ the Human Studies Laboratory of the Environmental Protection Agency@ in collaboration with the Coordinating Research Council@ included the Chattanooga area in its plans for a National Community Health Environmental Surveillance System (CHESS) in 1969. A joint study was conducted in four residential areas of Chattanooga with three schools in each area being involved. Health data included frequency of acute respiratory illness@ ventilatory performance of school children@ frequency of chronic respiratory disease symptoms@ and frequency and severity of asthma attacks in a panel of patients. The Environmental Protection Agency supported the health effects study@ while the Coordinating Research Council supported the effort to upgrade the NO2 air monitoring capabilities. The objective of CRC-APRAC Project No. CAPM-10-71 was to upgrade the NO2 monitoring capabilities for the Chattanooga exposure study. This report covers the activities of the chemiluminescent NO2 monitoring program in Chattanooga from the inception of the program through December 31@ 1973@and includes all pertinent information from the previous report [7].
API 4237-1974 history
1974API 4237-1974 Program for Upgrading the NO2 Instrumentation Employed in the 1972-1973 Chattanooga NO2 Exposure Study - Final Report