a two-week tunnel study was conducted in monterrey, mexico during june 2009 to characterizevolatile organic compound (voc) emissions from the local vehicle fleet and estimate the correspondingemission factors (efs). the loma larga tunnel (llt), a 532 meter-long structure that is mainly used by lightduty gasoline-powered vehicles was used as the experimental set-up. ambient air samples (2-hour a...

After examining the properties of several alternative forms of marketable permit systems for the control of air pollution, this paper proposes a system of pollution offsets as the most promising approach. Under the pollution-offset scheme, sources of emissions are free to trade emissions permits subject to the constraint of no violations of the predetermined air-quality standard at any receptor...

Air pollution is composed of a mixture of toxins, consisting of particles and gases emitted in large quantities from many different combustion sources, including cars and industries. A variety of anthropogenic and natural particle sources are present in ambient air. Throughout the past decade, the composition of air pollution has changed in developed countries from classical type 1 pollution, c...

This study investigates the spatial water quality pattern of seven stations located along the main Langat River. Environmetric methods, namely, the hierarchical agglomerative cluster analysis (HACA), the discriminant analysis (DA), the principal component analysis (PCA), and the factor analysis (FA), were used to study the spatial variations of the most significant water quality variables and t...

Heavy metals (HMs) in sewage sludge have become the crucial limiting factors for land use application. Samples were collected and analyzed from 32 waste water treatment plants (WWTPs) in the Shanxi Province, China. HM levels in sewage sludge were assessed. The multivariate statistical method principal component analysis (PCA) was applied to identify the sources of HMs in sewage sludge. HM pollu...

nowadays, with population growth in urban areas, providing safe water and health is considered basic needs of human, alongside the various pollutants due to urban activities, agriculture and industrial areas on adjacent ranges into urban water resources around the environment is such that study necessary to prevent the pollution of water resources and identification of pollution sources shows. ...

A procedure for assessing harbour pollution by heavy metals and PAH and the possible sources of contamination is proposed. The procedure is based on a ratio-matching method applied to the results of principal component analysis (PCA), and it allows discrimination between point and nonpoint sources. The approach can be adopted when many sources of pollution can contribute in a very narrow coasta...

Introduction Perfluorinated compounds (PFCs) have been detected from various environmental matrices even in Arctic, and known to be ubiquitous pollutants. Fluorotelomer alcohols (FTOHs) and fluorooctane sulfonamidoethanol (FOSE), which can be degraded to perfluorooctanoate (PFOA) and perfluorooctane sulfonate (PFOS), respectively, spread to all over the globe through atmosphere and are consider...