| Revista: | Revista brasileira de geofisica |
| Base de datos: | PERIÓDICA |
| Número de sistema: | 000338715 |
| ISSN: | 0102-261X |
| Autores: | Marani, Luciano1 Alvala, Plinio Carlos1 Kirchhoff, Volker Walter Johann Heinrich1 |
| Instituciones: | 1Instituto Nacional de Pesquisas Espaciais, Coordenacao Geral de Ciencias Espaciais e Atmosfericas, Sao Jose dos Campos, Sao Paulo. Brasil |
| Año: | 2006 |
| Periodo: | Oct-Dic |
| Volumen: | 24 |
| Número: | 4 |
| Paginación: | 459-466 |
| País: | Brasil |
| Idioma: | Portugués |
| Tipo de documento: | Artículo |
| Enfoque: | Analítico, descriptivo |
| Resumen en inglés | A study of atmospheric chlorofluorocarbons CCl3F (CFC-11) and CCl2F2 (CFC-12) was performed in the Metropolitan Region of S˜ao Paulo – MRSP (23.5◦S; 46.6◦W) during 2002. For the quantitative determination of the CFC concentration, a gas chromatograph with electron capture detector (ECD) was optimized with relative precision of 1.0%. In the MRSP, the observations of CFC-12 showed that there are large spatial and temporal variations in their concentrations (540.1 to 1395.8 pptv), while the CFC-11 concentrations did not show any statistically significant variation. Daily samplings were performed in June, July, August, September, November and December and showed that the emissions of CFC-12 were concentrated on weekdays (Monday to Friday), relating the emissions of this gas with its use in air conditioning and refrigeration systems of commercial and industrial buildings. The spatial variation observed in monthly campaigns in MRSP (April, May, June, July, August and September) and their matching with the predominant local wind direction evidencing the existence of a source region of CFC-12, located in the central area of the city. These results are indicative that emissions of CFC-12 are still significant. The monitoring of the mixing ratios of these gases in large cities like S˜ao Paulo can add to evaluate how the countries are following the Montreal Protocol, which restricts the production and trading of CFCs in developing countries, and schedule their banishment to 2010 |
| Resumen en portugués | Este trabalho apresenta um estudo das concentracoes atmosfericas dos clorofluorcarbonos CCl3F (CFC-11) e CCl2F2 (CFC-12) na Regiao Metropolitana de Sao Paulo – RMSP (23,5◦S; 46,6◦O) durante o ano de 2002. Para a determinacao quantitativa da concentracao dos CFCs foi utilizado um cromatografo a gas equipado com um detector de captura eletronica (DCE) otimizado para a an´alise dos CFCs 11 e 12 com precisao relativa de 1,0%. Na RMSP, as observacoes de CFC-12 mostraram a existencia de grande variacao espacial e temporal em suas concentracoes (de 540,1 ate 1395,8 pptv), enquanto as concentracoes de CFC-11 nao apresentaram qualquer variacao estatıstica significativa. Amostragens diarias realizadas nos meses de junho, julho, agosto, setembro, novembro e dezembro mostraram que as emissoes de CFC-12 estavam concentradas nos dias uteis, relacionando-as assim com seu uso em sistemas de ar condicionado e refrigeracao do setor comercial e industrial |
| Disciplinas: | Geociencias, Ingeniería |
| Palabras clave: | Ciencias de la atmósfera, Ingeniería ambiental, Clorofluorocarburos, Contaminación, Emisiones residuales, Variación estacional, Sao Paulo, Brasil |
| Keyword: | Earth sciences, Engineering, Atmospheric sciences, Environmental engineering, Chlorofluorocarbons, Pollution, Residual emissions, Seasonal variation, Sao Paulo, Brazil |
| Texto completo: | Texto completo (Ver PDF) |
