A Statistical Analysis of the Los Angeles Ambient Carbon Monoxide Data 1955–1972

Abstract

This paper presents a statistical analysis of some aspects of the ambient carbon monoxide data from 1955 to 1972 recorded at seven appropriately distributed locations in the Los Angeles Basin. Using modern time series methods and graphical techniques, an overall trend analysis of the movement of CO is given. Of special interest is a detailed study of the effect on the observed concentration level of CO due to (i) a change in the method of calibration of the measuring instrument In April 1968 and (ii) various control measures introduced since 1966. Also presented is an analysis of the seasonal variation of CO and the diurnal variation in weekdays and weekends. A major purpose of this study is to assess the influence of meteorological variables on the concentration level of the pollutant. Appropriate mathematical models are developed which relate CO to inversion base height, maximum mixing height, wind speed and direction, and traffic pattern. In addition, an analysis of the meteorological conditions during the days in which hourly concentration level of CO exceeded the Federal Air Quality Standard is given.