Search results for " quality index"

Low temperature headspace desorption of volatile organic compounds trapped in air sampling solid-supports

2009

Environmental context. The monitoring of volatile organic compounds (VOCs) in air is of great importance for air quality on both local and global scales. The determination of VOCs can be carried out by gas chromatography–mass spectrometry (GC-MS) after active or passive sampling and (high temperature) thermal desorption. An attractive alternative would be to combine GC-MS with headspace (HS) systems as it allows simpler, faster, low temperature desorption. We present here the first report of HS-GC-MS for the determination of VOCs in air sampled using solid supports. Abstract. The use of a headspace (HS) for low temperature desorption of VOCs, previously sorbed from indoor air on solid supp…

Functional Principal Component Analysis for the explorative analysis of multisite-multivariate air pollution time series with long gaps

2013

The knowledge of the urban air quality represents the first step to face air pollution issues. For the last decades many cities can rely on a network of monitoring stations recording concentration values for the main pollutants. This paper focuses on functional principal component analysis (FPCA) to investigate multiple pollutant datasets measured over time at multiple sites within a given urban area. Our purpose is to extend what has been proposed in the literature to data that are multisite and multivariate at the same time. The approach results to be effective to highlight some relevant statistical features of the time series, giving the opportunity to identify significant pollutants and…

Network design for surface water quality monitoring in a road construction project using Gamma Test theory

2021

Road construction has a negative environmental impact on the surrounding aquatic environment, requiring the continuous monitoring of surface water quality. Here, optimization of the water quality monitoring network (WQMN) is an essential step in supporting the sustainable development of road construction projects. This study introduces Gamma Test theory (GTT) as a practical method for optimizing the WQMN of surface waters during road construction. The water quality index (WQI) was computed in 48 monitoring stations for six monitoring periods from 2017 to 2019; data was acquired from a primary monitoring network over a new highway in southern Norway. Based on the results, it is possible to r…

Development of a versatile, easy and rapid atmospheric monitor for benzene, toluene, ethylbenzene and xylenes determination in air

2009

Abstract A new procedure for the passive sampling in air of benzene, toluene, ethylbenzene and xylene isomers (BTEX) is proposed. A low-density polyethylene layflat tube filled with a mixture of solid phases provided a high versatility tool for the sampling of volatile compounds from air. Several solid phases were assayed in order to increase the BTEX absorption in the sampler and a mixture of florisil and activated carbon provided the best results. Direct head-space-gas chromatography–mass spectrometry (HS-GC–MS) measurement of the whole deployed sampler was employed for a fast determination of BTEX. Absorption isotherms were used to develop simple mathematical models for the estimation of…

Cardiovascular effects of air pollution

2017

Air pollution is composed of particulate matter (PM) and gaseous pollutants, such as nitrogen dioxide and ozone. PM is classified according to size into coarse particles (PM 10), fine particles (PM 2.5) and ultrafine particles. We aim to provide an original review of the scientific evidence from epidemiological and experimental studies examining the cardiovascular effects of outdoor air pollution. Pooled epidemiological studies reported that a 10 μg/m 3 increase in long-term exposure to PM 2.5 was associated with an 11% increase in cardiovascular mortality. Increased cardiovascular mortality was also related to long-term and short-term exposure to nitrogen dioxide. Exposure to air pollution…

TRAFFIC FLOW HYPOTHETICAL MODELLING FOR AIR QUALITY IMPROVEMENT AND PLANNING PURPOSES

2019

The main emphasis of this research was to describe air pollution level and dispersion in a typical street canyon (Valdemara Street in Riga (Latvia) city centre), afterward to postulate potential development scenarios and perform modelling in order to understand the influence on air pollution level. For this purpose special mathematical model was used - Operational Street Pollution Model (OSPM), which was developed by the National Environmental Research Institute in Denmark. Following development scenarios were tested: (1) realistic environmentally friendly - decrease of traffic flow by 50 %, as according to street interviews about 36 - 50 % of drivers are ready to change driving habits from…

2013

Abstract. It has become possible to retrieve the global, long-term trends of trace gases that are important to atmospheric chemistry, climate, and air quality from satellite data records that span more than a decade. However, many of the satellite remote sensing techniques produce measurements that have variable sensitivity to the vertical profiles of atmospheric gases. In the case of constrained retrievals like optimal estimation, this leads to a varying amount of a priori information in the retrieval and is represented by an averaging kernel (AK). In this study, we investigate to what extent the estimation of trends from retrieved data can be biased by temporal changes of averaging kernel…

From COVID-19 to future electrification: Assessing traffic impacts on air quality by a machine-learning model

2021

The large fluctuations in traffic during the COVID-19 pandemic provide an unparalleled opportunity to assess vehicle emission control efficacy. Here we develop a random-forest regression model, based on the large volume of real-time observational data during COVID-19, to predict surface-level NO(2), O(3), and fine particle concentration in the Los Angeles megacity. Our model exhibits high fidelity in reproducing pollutant concentrations in the Los Angeles Basin and identifies major factors controlling each species. During the strictest lockdown period, traffic reduction led to decreases in NO(2) and particulate matter with aerodynamic diameters <2.5 μm by –30.1% and –17.5%, respectively, bu…

Differential Effects of Biologics on Psoriasis-Related Vascular Inflammation and Risk of Thrombosis

2020

Programa Estatal de I+D+i Orientada a los Retos de la Sociedad from Ministerio de Ciencia, Innovación y Universidades and European Regional Development Fund (Spain) [RTI2018-094436-B-I00]; Ministerio de Sanidad y Consumo CIBERehd (Spain) [CB06/04/0071]; Generalitat Valenciana (Spain) [PROMETEO/2018/141]; Proyectos Grupos Emergentes [GV/2019/043]; and Universidad Europea (Spain) (2018/UEM32 and 2019/UEM29]. 8.551 JCR (2020) Q1, 4/69 Dermatology 1.951 SJR (2020) Q1, 54/438 Biochemistry No data IDR 2020 UEV

Profiles and seasonal distribution of airborne fungi in indoor and outdoor environments at a French hospital

2009

International audience; A one-year prospective survey of fungal air contamination was conducted in outdoor air and inside two haematological units of a French hospital. Air was sampled with a portable Air System Impactor. During this period of survey, the mean viable fungal load was 122.1 cfu/m(3) in outdoor air samples, and 4.1 and 3.9 cfu/m(3) in samples from adult and pediatric haematology units, respectively. In outdoor samples, Cladosporium was the dominant genus (55%) while in the clinical units, Penicillium sp. (23 to 25%), Aspergillus sp. (15 to 23%) and Bjerkandera adusta (11 to 13%) were the most frequently recovered airborne fungi. The outdoor fungal load was far higher in autumn…