Microbiological monitoring of drinking water for fecal contamination is a legal requirement in most countries. The objective is to protect the users from water borne disease. We expressed The United States Drinking Water Regulations (DWR) in statistical terms and examined their probabilistic characteristics both analytically and by simulations. The DWR set upper limits on the mean coliform count and on the individual counts of all samples examined per month. Our results show that only an upper limit on the mean coliform count is basically sufficient for DWR.
AN CARBONEZ
University Center for Statistics
Katholieke Universiteit Leuven
W. de Croylaan 52 B
Heverlee, B-3001, Belgium
An.Carbonez@ucs.kuleuven.ac.be
Estimation of Environmental Control
Limits and Probabilities
Abdel H. El-Shaarawi, Jef L.
Teugels, and An Carbonez
Typically Environmental Regulations
(ER) specify compliance statistics Cn based on Control Limits (LS) and
n measurements x1, x2,...., x n of the concentration of a pollutant during
a fixed time period. The performance of ER in a particular situation depends
on the distributional characteristics of Cn and therefore on the model
for the variability of the measurements. We propose to study such performance
by estimating the Realized Control Limits (RLS) when the probability of
exceedance, P{Cn>RLS} is a pre-specified value P{Cn>LS} for given
LS.
We assumed a general location scale
model with covariates for the measurements and then specialized our analysis
to the lognormal distribution which is commonly used to model environmental
data. In this case, the uniformly minimum variance unbiased estimates for
the above two quantities are derived. We used a Canadian bacteriological
data set to motivate and illustrate the methodology of this paper.
ABDEL H. EL-SHAARAWI
National Water Research Institute
Burlington, Ontario L7R 4A6, Canada
abdel.el-shaarawi@cciw.ca
The Setting of International Aviation
Emission Standards:
A Case Study of the International
Community at Work
Mara Lee McLaren
This paper presents a case study
of how international emission standards for the aviation industry are set.
It is the author's hope that this real-life example of international policy
development related to climate change, and the role of economic and statistical
analysis within it, will prove instructive to environmental analysts, economists
and statisticians.
In 1998, the Committee on Aviation
Environmental Protection, a committee of the International Civil Aviation
Organization, succeeded in passing a resolution that will impose new, more
stringent international emission standards on jet aircraft engines. This
paper explores the inner workings of the committee from both a policy and
analytical perspective. It describes the quantitative analyses undertaken
and challenges faced in assessing the environmental and financial impacts
of options under review. It also addresses the political and economic realities
involved in developing consensus across nations, and in the presence of
strong industry interests.
MARA LEE McLAREN
Consulting and Audit Canada
112 Kent Street, Tower B,
Ottawa, Ontario K1A 0S5, Canada
Mara.Lee.McLaren@cac.gc.ca
