Surface waters to be used as resource for drinking water, waste water and sludge produced in treatment processes are very complex media containing soluble, colloidal and particulate matter. Apart from inert or dead matter the colloidal and particulate phase is mainly composed by organic bio-particles (viruses, bacteria, protozoa). Treatment processes like disinfection of potable water, hygienis...

Particulate organic matter (POM) is an important source of energy in aquatic systems, where decomposition rates have traditionally been studied using the litter-bag technique. However, this method has limitations for estimating in situ decomposition rates, especially for fine particles. In this study the litter-bag technique is combined with measurements of microbial enzyme activities to estima...

BACKGROUND persons who are 65 years or older often spend an important part of their lives indoors thus adverse indoor climate might influence their health status. OBJECTIVE to evaluate the influence of indoor air quality and contaminants on older people's respiratory health. DESIGN cross-sectional study. SETTING 21 long-term care residences (LTC) in the city of Porto, Portugal. SUBJECTS...

Ionization air purifiers are increasingly used to remove aerosol particles from indoor air. However, certain ionization air purifiers also emit ozone. Reactions between the emitted ozone and unsaturated volatile organic compounds (VOC) commonly found in indoor air produce additional respirable aerosol particles in the ultrafine (<0.1 microm) and fine (<2.5 microm) size domains. A simple kinetic...

The fouling of a spiral wound reverse osmosis (RO) membrane after nearly 1 year of service in a brackish water treatment plant was investigated using optical and electron microscopic methods, Fourier transform infrared spectroscopy (FTIR) and inductively coupled plasma atomic emission spectrometry (ICP-AES). Both the top surface and the cross-section of the fouled membrane were analysed to moni...

Particulate matter was measured in Conroe, Texas (~60 km north of downtown Houston, Texas) during the September 2013 DISCOVER-AQ campaign to determine the sources of particulate matter in the region. The measurement site is influenced by high biogenic emission rates as well as transport of anthropogenic pollutants from the Houston metropolitan area and is therefore an ideal location to study an...

Receptor models are used to identify and quantify source contributions to particulate matter and volatile organic compounds based on measurements of many chemical components at receptor sites. These components are selected based on their consistent appearance in some source types and their absence in others. UNMIX, positive matrix factorization (PMF), and effective variance are different soluti...

The objective of this paper is to demonstrate an approach to characterize the spatial variability in ambient air concentrations using mobile platform measurements. This approach may be useful for air toxics assessments in Environmental Justice applications, epidemiological studies, and environmental health risk assessments. In this study, we developed and applied a method to characterize air to...

Heterotrophic activities on sinking particulate matter (SPM) play an important role in SPM fluxes in the ocean. To demonstrate regional differences in heterotrophic activities on SPM, we measured heterotrophic bacterial production (HBP) in seawater (HBP(SW)) and SPM (HBP(SPM)) as well as potential extracellular enzyme activity (EEA) in SPM on a transect along 155°E in the western North Pacific ...