The Impacts of Peroxyacetyl Nitrate in the Atmosphere of Megacities and Large Urban Areas: A Historical Perspective

Author(s):  
Jeffrey S. Gaffney ◽  
Nancy A. Marley
2021 ◽  
Vol 3 (5) ◽  
pp. 3133-3144
Author(s):  
Luciane Tasca ◽  
Sabrina Ferretti Do Amaral

O presente artigo se insere na temática da reestruturação do espaço em cidades médias brasileiras e apresenta como principal objetivo analisar a implantação de Projetos Urbanos de relevante impacto na estrutura da cidade de Juiz de Fora, MG. Segundo perspectiva histórica, desde a década de 1970, o município vem passando por alterações significativas na sua estrutura, resultantes de sua expansão e do surgimento de novas centralidades. Destaca-se, no entanto, que desde o ano 2000, Juiz de Fora se tornou palco de Projetos Urbanos (especialmente na sua Região Sul), a partir de mudanças implementadas pela administração pública focadas no planejamento estratégico e no empresariamento urbano.  Percebe-se assim, o surgimento de um novo núcleo de atratividade num processo crescente de alteração da dinâmica urbana do município. Diante da ineficiente ação por parte do poder público local, somada à falta de políticas urbanas integradas ao planejamento espacial da cidade, este trabalho se justifica por se apresentar como um meio de explorar e debater idéias que contribuam efetivamente para a qualidade urbana da cidade.   This paper is part of the issue spatial restructuring in Brazilian average cities and has as its objective to analyze the implementation of urban projects of significant impact on the structure of Juiz de Fora, MG. According to a historical perspective, since the 1970s, the city has been undergoing significant changes in its structure, resulting from its expansion and the emergence of new centers.  Stands out, however, from the year 2000, Juiz de Fora became the scene of urban projects (deployed in its Southern Region), from the implemented changes by the government focused on the strategic planning and the urban enterprising: It is noticed, the rise of a new core attractiveness distinct from the others: excluding and in order to threaten the dynamic urban areas.  In front of the ineficcient action from the local government, together with the lack of integrated urban policies to the spatial planning of the city, this work is justified by presenting itself as a way to explore and discuss ideas that contribute effectively to the quality of the town.


2021 ◽  
Vol 3 (5) ◽  
pp. 2922-2934
Author(s):  
Luciane Tasca ◽  
Sabrina Ferretti Do Amaral

O presente artigo se insere na temática da reestruturação do espaço em cidades médias brasileiras e apresenta como principal objetivo analisar a implantação de Projetos Urbanos de relevante impacto na estrutura da cidade de Juiz de Fora, MG. Segundo perspectiva histórica, desde a década de 1970, o município vem passando por alterações significativas na sua estrutura, resultantes de sua expansão e do surgimento de novas centralidades. Destaca-se, no entanto, que desde o ano 2000, Juiz de Fora se tornou palco de Projetos Urbanos (especialmente na sua Região Sul), a partir de mudanças implementadas pela administração pública focadas no planejamento estratégico e no empresariamento urbano.  Percebe-se assim, o surgimento de um novo núcleo de atratividade num processo crescente de alteração da dinâmica urbana do município. Diante da ineficiente ação por parte do poder público local, somada à falta de políticas urbanas integradas ao planejamento espacial da cidade, este trabalho se justifica por se apresentar como um meio de explorar e debater idéias que contribuam efetivamente para a qualidade urbana da cidade. This paper is part of the issue spatial restructuring in Brazilian average cities and has as its objective to analyze the implementation of urban projects of significant impact on the structure of Juiz de Fora, MG. According to a historical perspective, since the 1970s, the city has been undergoing significant changes in its structure, resulting from its expansion and the emergence of new centers.  Stands out, however, from the year 2000, Juiz de Fora became the scene of urban projects (deployed in its Southern Region), from the implemented changes by the government focused on the strategic planning and the urban enterprising: It is noticed, the rise of a new core attractiveness distinct from the others: excluding and in order to threaten the dynamic urban areas.  In front of the ineficcient action from the local government, together with the lack of integrated urban policies to the spatial planning of the city, this work is justified by presenting itself as a way to explore and discuss ideas that contribute effectively to the quality of the town.  


2021 ◽  
Vol 13 (24) ◽  
pp. 14068
Author(s):  
Rares Halbac-Cotoara-Zamfir ◽  
Carla Sofia Santos Ferreira ◽  
Luca Salvati

Urbanization is a dynamic process performed at the expense of natural and/or semi-natural areas, with direct impacts on the ecosystem services provided to human society. The increasing population density in urban areas and the associated demand for housing and public services have led to progressive changes in the structure, architecture, and design of urban areas. The present study analyzes long-term urban development in Western Romania, focusing on green/blue areas’ strategies in Timisoara over centuries. The empirical results of a literature review carried out with a historical perspective have delineated the time periods that favored “urban green development” (1716–1918 and 1918–1940) and those restricting their development (1940–2000), as well as the factors that influenced long-term urbanization dynamics and the evolution of green/blue areas. These factors can be generalized to other socioeconomic contexts in Eastern Europe. Characteristic issues of this geographical area impacting the evolution of urban green/blue areas include (i) common historical aspects (e.g., the influence of geo-political and strategic dimensions, the dominations of former great empires such as the Turkish empire and the communist period) and (ii) population migration after 1990.


Author(s):  
William W. Thomson ◽  
Elizabeth S. Swanson

The oxidant air pollutants, ozone and peroxyacetyl nitrate, are produced in the atmosphere through the interaction of light with nitrogen oxides and gaseous hydrocarbons. These oxidants are phytotoxicants and are known to deleteriously affect plant growth, physiology, and biochemistry. In many instances they induce changes which lead to the death of cells, tissues, organs, and frequently the entire plant. The most obvious damage and biochemical changes are generally observed with leaves.Electron microscopic examination of leaves from bean (Phaseolus vulgaris L.) tobacco (Nicotiana tabacum L.) and cotton (Gossipyum hirsutum L.) fumigated for .5 to 2 hours with 0.3 -1 ppm of the individual oxidants revealed that changes in the ultrastructure of the cells occurred in a sequential fashion with time following the fumigation period. Although occasional cells showed severe damage immediately after fumigation, the most obvious change was an enhanced clarity of the cell membranes.


1996 ◽  
Vol 22 (3) ◽  
pp. 167-174
Author(s):  
J A Cantrill ◽  
B Johannesson ◽  
M Nicholson ◽  
P R Noyce

1990 ◽  
Vol 23 (4) ◽  
pp. 571-575
Author(s):  
Charles F. Koopmann, ◽  
Willard B. Moran

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