Influence of the public transportation system on the air quality of a major urban center. A case study: Milan, Italy

A sampling campaign was conducted in the city of Milan, Italy before and during a transportation strike in January 2004. This strike provided a unique opportunity to investigate the influence of public transportation on the air quality in a major metropolitan area. Twenty-four air samples were collected each day around the city on January 2nd, 7th and 9th. The samples were analyzed for methane, carbon monoxide, non-methane hydrocarbons (NMHCs), halocarbons and alkyl nitrates. Significant differences in the mixing ratios were observed among the three days of sampling, with January 2nd showing the lowest concentrations as a result of decreased activity in the city during the holiday season. January 9th showed the highest NMHC concentrations because of increased vehicular activity in the city due to a public transportation strike. This paper investigates the correlation between the increased number of vehicles and decreased air quality because of a reduction in public transportation. Computer simulations were able to reproduce measurements of ozone production during the January 2004 strike and a July 2005 strike. The measurements and simulations suggest that reduced VOC emissions due to the existence of public transportation lowers peak ozone by 11-33% during the summer months. © 2008 Elsevier Ltd. All rights reserved

Development and initial evaluation of a dynamic species-resolved model for gas phase chemistry and size-resolved gas/particle partitioning associated with secondary organic aerosol formation

A module for predicting the dynamic evolution of the gas phase species and the aerosol size and composition distribution during formation of secondary organic aerosol (SOA) is presented. The module is based on the inorganic gas-aerosol equilibrium model Simulating the Composition of Atmospheric Particles at Equilibrium 2 (SCAPE2) and updated versions of the lumped Caltech Atmospheric Chemistry Mechanism (CACM) and the Model to Predict the Multiphase Partitioning of Organics (MPMPO). The aerosol phase generally consists of an organic phase and an aqueous phase containing dissolved inorganic and organic components. Simulations are presented in which a single salt (either dry or aqueous), a volatile organic compound, and oxides of nitrogen undergo photo-oxidation to form SOA. Predicted SOA mass yields for classes of aromatic and biogenic hydrocarbons exhibit the proper qualitative behavior when compared to laboratory chamber data. Inasmuch as it is currently not possible to represent explicitly aerosol phase chemistry involving condensed products of gas phase oxidation, the present model can be viewed as the most detailed SOA formation model available yet will undergo continued improvement in the future

Secondary organic aerosol 1. Atmospheric chemical mechanism for production of molecular constituents

This series of three papers addresses the representation of secondary organic aerosol (SOA) in atmospheric models. SOA forms when gas-phase organic species undergo oxidation, leading to products of sufficiently low vapor pressure that can partition between the gas and aerosol phases. The present paper, part 1, is devoted to the development of a gas-phase atmospheric chemical mechanism designed to represent ozone chemistry as well as formation of individual organic oxidation products that are capable of forming SOA. The ozone chemistry in the mechanism draws upon the recent work of Stockwell et al. [1997] and Jenkin et al. [1997] and SAPRC-97 and SAPRC-99 (available from W.P.L. Carter at http://helium.ucr.edu/~carter/). The mechanism is evaluated in the three-dimensional California Institute of Technology (CIT) model [Meng et al., 1998] by simulating gas-phase concentrations in the South Coast Air Basin (SoCAB) of California over the period 27–29 August 1987. Total predicted concentrations of gas-phase SOA compounds are compared with levels of SOA that have been inferred on the basis of ambient organic aerosol measurements during this period. These predicted concentrations indicate that the total gas-phase potential of SOA-forming compounds can account for observed aerosol concentrations. Part 2 develops a thermodynamic gas–aerosol partitioning module, and part 3 presents a full three-dimensional simulation of gas and aerosol levels in the SoCAB during a 1993 episode

Estimating child labour in Jordan 1991-2005

This report is a moderate attempt to estimate the size of child labour in Jordan during the years 1991-2001 and to make short-range projections for the period of 2002-2005. It comes as a part of the efforts exerted by the Ministry of Labour to know the size of the problem and to prevent the spread of child labour, in view of the Ministry's realisation of the paramount role of the child. The report depends mainly on the database of the Child Labour Unit at the Ministry of Labour and annual growth of students and dropouts. Combining these two resources, the report utilises statistical estimation and prediction techniques in making these estimations and projections. The present report provides estimates and short-range projections for the size of child labour over the period 1991-2005 under three different scenarios of future trends for the number of working children. These estimates and projections are in no way an accurate provision of the future trend of child labour. They do illustrate, however, the evolution of child labour under possible -and hypothetical- scenarios of future levels of some educational variables. The report uses three scenarios (high, medium, and low) of future trends for the number of working children. According to the medium estimation, the number of working children is estimated to be about 40 thousand in 1991 and 39 thousand in 2001. The number of working children is projected to grow gradually thereafter making the projected figure to reach about 42 thousand in 2005

Response to Special Educational Needs and Teaching Efforts in Elementary School

De acuerdo con la Ley de Igualdad de Oportunidades para las Personas con Discapacidad en Costa Rica (Ley N.º 7600), los maestros deben recibir y atender individuos con necesidades educativas especiales (NEE) dentro de sus clases regulares y saber cómo aplicar las diferentes adecuaciones curriculares. Por lo tanto, conocer la cantidad y el tipo de NEE que atienden los educadores y las áreas en las que estos expresan requerir facultarse, permite mejorar considerablemente la calidad y la eficiencia de las actualizaciones profesionales que se brindan a los docentes y la atención asertiva de las NEE. Para recolectar esta información, se realizó una entrevista a quince maestros de primero a sexto grado en una escuela privada en Moravia, Costa Rica. Los resultados visibilizan que las principales necesidades educativas que ellos intentan solventar son los trastornos de atención y los problemas emocionales. Las principales limitaciones que enfrentan los educadores para atender las NEE son falta de tiempo y poco apoyo de las familias. Las áreas en las que indicaron requerir capacitación son relacionadas con la aplicación eficaz de adecuaciones curriculares y las metodolo gías específicas para las NEE. La investigación presenta utilidad tanto para la docencia como para la Psicopedagogía

Estimate of global atmospheric organic aerosol from oxidation of biogenic hydrocarbons

The results from a series of outdoor chamber experiments establishing the atmospheric aerosol-forming potential of fourteen terpenoid hydrocarbons have been used to estimate the annual amount of secondary organic aerosol formed globally from compounds emitted by vegetation. Hydroxyl radical, ozone, and nitrate radical oxidation each contribute to aerosol formation in full-photooxidation experiments; because oxidation by nitrate radical under ambient, remote conditions is likely to be negligible, parameters describing aerosol formation from hydroxyl radical and ozone reaction only are developed. Chamber results, temporally and spatially resolved, compound-specific estimates of biogenic hydrocarbon emissions, and hydroxyl radical and ozone fields are combined to lead to an estimate for atmospheric secondary organic aerosol formed annually from biogenic precursors of 18.5 Tg, a number smaller than the previously published estimate of 30–270 Tg [Andreae and Crutzen, 1997]

Estimating child labour in Jordan 1991-2005

This report is a moderate attempt to estimate the size of child labour in Jordan during the years 1991-2001 and to make short-range projections for the period of 2002-2005. It comes as a part of the efforts exerted by the Ministry of Labour to know the size of the problem and to prevent the spread of child labour, in view of the Ministry's realisation of the paramount role of the child. The report depends mainly on the database of the Child Labour Unit at the Ministry of Labour and annual growth of students and dropouts. Combining these two resources, the report utilises statistical estimation and prediction techniques in making these estimations and projections. The present report provides estimates and short-range projections for the size of child labour over the period 1991-2005 under three different scenarios of future trends for the number of working children. These estimates and projections are in no way an accurate provision of the future trend of child labour. They do illustrate, however, the evolution of child labour under possible -and hypothetical- scenarios of future levels of some educational variables. The report uses three scenarios (high, medium, and low) of future trends for the number of working children. According to the medium estimation, the number of working children is estimated to be about 40 thousand in 1991 and 39 thousand in 2001. The number of working children is projected to grow gradually thereafter making the projected figure to reach about 42 thousand in 2005

Emission estimates of HCFCs and HFCs in California from the 2010 CalNex study

The CalNex 2010 (California Research at the Nexus of Air Quality and Climate Change) study was designed to evaluate the chemical composition of air masses over key source regions in California. During May to June 2010, air samples were collected on board a National Oceanic and Atmospheric Administration (NOAA) WP-3D aircraft over the South Coast Air Basin of California (SoCAB) and the Central Valley (CV). This paper analyzes six effective greenhouse gases - chlorodifluoromethane (HCFC-22), 1,1-dichloro-1-fluoroethane (HCFC-141b), 1-chloro-1,1-difluoroethane (HCFC-142b), 2-chloro-1,1,1,2-tetrafluoroethane (HCFC-124), 1,1,1,2- tetrafluoroethane (HFC-134a), and 1,1-difluoroethane (HFC-152a) - providing the most comprehensive characterization of chlorofluorocarbon (CFC) replacement compound emissions in California. Concentrations of measured HCFCs and HFCs are enhanced greatly throughout the SoCAB and CV, with highest levels observed in the SoCAB: 310 ± 92 pptv for HCFC-22, 30.7 ± 18.6 pptv for HCFC-141b, 22.9 ± 2.0 pptv for HCFC-142b, 4.86 ± 2.56 pptv for HCFC-124, 109 ± 46.4 pptv for HFC-134a, and 91.2 ± 63.9 pptv for HFC-152a. Annual emission rates are estimated for all six compounds in the SoCAB using the measured halocarbon to carbon monoxide (CO) mixing ratios and CO emissions inventories. Emission rates of 3.05 ± 0.70 Gg for HCFC-22, 0.27 ± 0.07 Gg for HCFC-141b, 0.06 ± 0.01 Gg for HCFC-142b, 0.11 ± 0.03 Gg for HCFC-124, 1.89 ± 0.43 Gg for HFC-134a, and 1.94 ± 0.45 Gg for HFC-152b for the year 2010 are calculated for the SoCAB. These emissions are extrapolated from the SoCAB region to the state of California using population data. Results from this study provide a baseline emission rate that will help future studies determine if HCFC and HFC mitigation strategies are successful. Key PointsHCFC and HFC emissions are calculated for the year 2010 for the SoCABEmissions are extrapolated to the state of CaliforniaEmissions are calculated using CalNex field measurements © 2013. American Geophysical Union. All Rights Reserved