PROGRAM FOR UPGRADING THE NO2 INSTRUMENTATION EMPLOYED IN THE 1972 CHATTANOOGA NO2 EXPOSURE STUDY - FINAL REPORT
|Publication Date:||14 April 1973|
Much effort has been expended in attempting to document health effects attributable to atmospheric nitrogen oxides. In connection with this effort, the Chattanooga,... View More
Much effort has been expended in attempting to document health effects attributable to atmospheric nitrogen oxides. In connection with this effort, the Chattanooga, Tennessee 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 was conducted from November 1968 to April 1969 among families residing in an area of relatively high NO2 exposure; in an area of elevated suspended particulate exposure; and in two control areas in greater Chattanooga. Respiratory illness rates were consistently higher in all family segments in the high NO2 exposure area than in the other areas where rates were averaged for the entire twenty-four weeks of study . Significantly, increased bronchitis morbidity was reported among elementary school children exposed for two and three years and infants exposed for three years to elevated levels of NO2 in ambient air . A study conducted in 1970-71 of parents of senior high school students in the Chattanooga region showed that those parents living in high NO2 exposure areas had a significantly lower forced expiratory volume that did those living in low NO2 exposure areas and the control area .
The usefulness of the results of the previous studies and current on going studies depends to a large extent on the validity of the atmospheric monitoring data obtained at the sampling stations.
Previous studies conducted in Chattanooga and elsewhere have been hampered by the absence of a reliable and accurate method for monitoring sample. Recent investigations [4, 5, 6] have shown that the reference method (NASN modification of Jacobs-Hochheiser) possesses inherent deficiencies that raise questions as to the accuracy and 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 NO2 on human health, the Human Studies Laboratory of the Environmental Protection Agency, in collaboration with the Coordinating Research Council, has included the Chattanooga, Tennessee area in its plans for a National Community Health Environmental Surveillance System (CHESS). A joint study is currently being conducted in four residential areas of Chattanooga with three schools in each area being involved. Health data includes 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 is supporting the health effects study, while the Coordinating Research Council portion of the study is supporting the upgrading of the NO2 air monitoring capabilities for the Chattanooga study.
The objective of CRC-APRAC Project No. CAPM-10-71, is then, to upgrade the NO2 monitoring capabilities for the Chattanooga exposure study to a point such that the air quality data when the observed health effects can be used to establish a meaningful and equitable air quality standard for NO2.View Less