Eduardo Monteiro Martins

Understanding Ozone Concentrations During Weekdays and Weekends in the Urban Area of the City of Rio de Janeiro

In different cities around the world, higher ozone concentrations are observed during weekends for various reasons. This study aims to determine the causes of this effect in the city of Rio de Janeiro based on measurements obtained at three automatic air quality monitoring stations in the Bangu, Campo Grande and Iraja neighborhoods between 2012 and 2013. Variations in the solar radiation and hourly carbon monoxide, nitrogen oxides, non-methane hydrocarbons, ozone and particulate matter concentrations were determined. The Bangu station showed the lowest ozone concentration differences between the weekdays and weekends (8.9%) and recorded the highest ozone concentrations and largest number of exceedances. The low ozone consumption by nitrogen oxide resulted in the high ozone concentrations at the Bangu station. In addition, the volatile organic compounds (VOC)/nitrogen oxides (NOx) ratio for this station was evaluated for each day of the week between 6 and 9 AM, and the observed VOC/NOx ratios were higher at the Campo Grande and Iraja stations. We concluded that the weekend effect occurred at all three of the evaluated stations, with greater intensity at the Campo Grande and Iraja stations. The main cause of this weekend effect is the greater reductions in NO emissions over the weekends, which increase the VOC/NOx ratio.

BTEX no interior de salas de aula de spinning

Atividades Fisicas realizadas em ambientes fechados estao se tornando mais frequente. Estudos tem mostrado que as concentracoes de poluentes em ambientes interiores sao sempre maiores do que em ambiente abertos. Em locais fechados, onde sao realizados exercicios de forma regular, nao existe a preocupacao com a qualidade do ar, principalmente quando estao sendo realizadas atividades aerobicas. Neste estudo, foram medidas concentracoes de BTEX em uma sala de spinning e as concentracoes obtidas foram maiores do que as encontradas em ambientes ao ar livre. No entanto, uma atividade de pintura realizada na sala de spinning gerou concentracoes elevadas de todos os BTEX , e, em particular, o tolueno teve concentracoes muito maiores. No dia seguinte a realizacao da pintura, as concentracoes de todos os BTEX tinham aumentado significativamente e a concentracao de tolueno foi de 274.9 µg/m³. Apos a pintura na sala de spinning, o aumento foi de 91% para o benzeno, 907% para o tolueno, 182% para o etilbenzeno, 121% para o m+p-xileno e de 128% para o o-xileno.

The relationship between solvent use and BTEX concentrations in occupational environments

Indoor air quality is an increasing concern; it causes significant damage to health because it is recycled in confined environments for extended periods of time. Among the pollutants found in these environments, benzene, toluene, ethylbenzene, and xylenes (BTEX) are known for their potential toxic, mutagenic, and carcinogenic effects. This study monitored the BTEX concentrations in paint, carpentry, and varnish workplaces and evaluated the potential to cause adverse health effects on workers in these environments. Twenty samples were collected in workplaces, 20 samples were collected outside the area, and eight samples were taken of the products used. Samples were collected using coconut shell cartridges, and chemical analyses were performed by gas chromatography with mass spectrometry. Toluene presented higher indoor concentrations and indoor and outdoor ratios, indicating that the paint and varnish workplaces had significant BTEX sources. The highest benzene and toluene concentrations were obtained from the paint workshop, and higher concentrations of ethylbenzene and xylenes were obtained in the varnish workshop. The highest non-carcinogenic risks were obtained for m + p-xylenes in the varnish work place, and the second highest non-carcinogenic risk was also determined for the same workshop.

Volatile Organic Compounds in a Residential and Commercial Urban Area with a Diesel, Compressed Natural Gas and Oxygenated Gasoline Vehicular Fleet

Air samples were collected in a typical residential and commercial area in Rio de Janeiro, Brazil, where buses and trucks use diesel and light duty vehicles use compressed natural gas, ethanol, and gasohol (gasoline blended with ethanol) as fuel. A total of 66 C3–C12 volatile organic compounds (VOCs) were identified. The most abundant compounds, on a mass concentration basis, included propane, isobutane, i-pentane, m,p-xylene, 1,3,5-trimethylbenzene, toluene, styrene, ethylbenzene, isopropylbenzene, o-xylene and 1,2,4-trimethylbenzene. Two VOCs photochemical reactivity rankings are presented: one involves reaction with OH and the other involves production of ozone.

Utilização de Sistema de Informação Geográfica como ferramenta para gestão do monitoramento da qualidade do ar na Região Metropolitana do Rio de Janeiro

The concern with the air quality management in the city of Rio de Janeiro has increased in recent last years due to the great events that this city will receive in the near future. The use of a Geographic Information System as a tool for the air quality management was evaluated in this work. A new delimitation of air basins was proposed using the digital data suggesting the appearance of three new air basins and the change of the spatial configuration of the existing air basins.

Neutralização compensatória de carbono - estudo de caso: indústria do setor metal mecânico, Rio de Janeiro (RJ)

This research aims to quantify the contribution of emissions of greenhouse gases, released by a company in the metal-mechanic, in Rio de Janeiro (RJ). A survey of the activities that influence the GHG emissions of the Metal Master company was done. The calculation of greenhouse gas emissions was through the methodologies developed by the Intergovernmental Panel on Climate Change (IPCC) to fuel consumption, energy consumption, waste disposed in landfills, domestic sewage and industrial effluents. Of the total emissions into the atmosphere by the company under study, was obtained a value of 439 tons of CO2 equivalent, with 76.3 tons from fuel consumption by transport, 89 tons from the waste generated, 2.2 tons from effluents generates, 8.8 tons from consumption of electricity and 148 tons from domestic industrial processes. In the scenario where we contemplate the mitigation measures, such emissions are reduced to 397 tons of CO2 equivalent. If employee reforestation as the only way to neutralize the emissions of the company, it is necessary to restore plant to an area of 1.37 hectares.

Basicity and Acidity, from Prehistory to the Present Days

As it stands today, acidity and basicity are chemical concepts of broad scope and applicability. However, for a long time, both properties remain mysterious and misunderstood as a concept, although being relatively well known facing their sensory nature. Over the centuries, the acidity and basicity properties were finally associated with two well defined chemical groups acids and bases. In more recent times, these concepts were relativized. This article aims to present some historical and unusual aspects of this topic.