Abstract: Periodicities in the environmetric time series can be
idyllically assessed by utilizing periodic models. In this
communication fugitive emission of gases from open sewer channel
Lyari which follows periodic behaviour are approximated by
employing periodic autoregressive model of order p. The orders of
periodic model for each season are selected through the examination
of periodic partial autocorrelation or information criteria. The
parameters for the selected order of season are estimated individually
for each emitted air toxin. Subsequently, adequacies of fitted models
are established by examining the properties of the residual for each
season. These models are beneficial for schemer and administrative
bodies for the improvement of implemented policies to surmount
future environmental problems.
Abstract: In this communication a quantitative modeling
approach is applied to construct model for the exchange of gases
from open sewer channel to the atmosphere. The data for the
exchange of gases of the open sewer channel for the year January
1979 to December 2006 is utilized for the construction of the model.
The study reveals that stream flow of the open sewer channel
exchanges the toxic gases continuously with time varying scale. We
find that the quantitative modeling approach is more parsimonious
model for these exchanges. The usual diagnostic tests are applied for
the model adequacy. This model is beneficial for planner and
managerial bodies for the improvement of implemented policies to
overcome future environmental problems.