A queueing model to study the occurrence and duration of ozone exceedances in Mexico City |
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Authors: | Juan Martin Barrios Eliane R Rodrigues |
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Institution: | 1. Facultad de Ciencias, Universidad Nacional Autónoma de México, Circuito Exterior – Ciudad Universitaria, Mexico DF 04510, Mexico;2. Instituto de Matemáticas, Universidad Nacional Autónoma de México, Area de la Investigación Científica, Circuito Exterior – Ciudad Universitaria, Mexico DF 04510, Mexico |
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Abstract: | It is well known that long-term exposure to high levels of pollution is hazardous to human health. Therefore, it is important to study and understand the behavior of pollutants in general. In this work, we study the occurrence of a pollutant concentration's surpassing a given threshold (an exceedance) as well as the length of time that the concentration stays above it. A general N(t)/D/1 queueing model is considered to jointly analyze those problems. A non-homogeneous Poisson process is used to model the arrivals of clusters of exceedances. Geometric and generalized negative binomial distributions are used to model the amount of time (cluster size) that the pollutant concentration stays above the threshold. A mixture model is also used for the cluster size distribution. The rate function of the non-homogeneous Poisson process is assumed to be of either the Weibull or the Musa–Okumoto type. The selection of the model that best fits the data is performed using the Bayes discrimination method and the sum of absolute differences as well as using a graphical criterion. Results are applied to the daily maximum ozone measurements provided by the monitoring network of the Metropolitan Area of Mexico City. |
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Keywords: | Bayesian inference Markov chain Monte Carlo algorithms mixture models queueing models non-homogeneous Poisson models |
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