Street vendors in Mexico and day laborers in the United States, both groups of informal workers who labor in public space, face formidable structural obstacles to securing their rights as workers. Despite their apparent vulnerability, these informal workers have built perhaps the most powerful informal worker organizations in their countries. In this article, we explore and explain to the extent possible the sources, forms, and limits of this unexpected power. We explore organizational and strategic commonalities as well as differences and seek to explain both.

Among the new technologies developed for the heavy-duty fleet, the use of Selective Catalytic Reduction (SCR) aftertreatment system in standard Diesel engines associated with biodiesel/diesel mixtures is an alternative in use to control the legislated pollutants emission. Nevertheless, there is an absence of knowledge about the synergic behaviour of these devices and biodiesel blends regarding the emissions of unregulated substances as the Polycyclic Aromatic Hydrocarbons (PAHs) and Nitro-PAHs, both recognized for their carcinogenic and mutagenic effects on humans. Therefore, the goal of this study is the quantification of PAHs and Nitro-PAHs present to total particulate matter (PM) emitted from the Euro V engine fuelled with ultra-low sulphur diesel and soybean biodiesel in different percentages, B5 and B20. PM sampling was performed using a Euro V - SCR engine operating in European Stationary Cycle (ESC). The PAHs and Nitro-PAHs were extracted from PM using an Accelerated Solvent Extractor and quantified by GC-MS. The results indicated that the use of SCR and the largest fraction of biodiesel studied may suppress the emission of total PAHs. The Toxic Equivalent (TEQ) was lower when using 20% biodiesel, in comparison with 5% biodiesel on the SCR system, reaffirming the low toxicity emission using higher percentage biodiesel. The data also reveal that use of SCR, on its own, suppress the Nitro-PAHs compounds. In general, the use of larger fractions of biodiesel (B20) coupled with the SCR aftertreatment showed the lowest PAHs and Nitro-PAHs emissions, meaning lower toxicity and, consequently, a potential lower risk to human health. From the emission point of view, the results of this work also demonstrated the viability of the Biodiesel programs, in combination with the SCR systems, which does not require any engine adaptation and is an economical alternative for the countries (Brazil, China, Russia, India) that have not adopted Euro VI emission standards.

We locate this issue's papers on a spectrum of radicalism. We then examine that spectrum, and the governance mechanisms described, through the lens of a significant arena of urban counter-planning: the urban informal economy. Drawing on our own research on self-organization by informal workers and settlers, as well as broader literatures, we suggest useful lessons for reinventing urban governance.

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The authors thank the population of Paranaguá for their collaboration to carry out the experimental activities. In the same way, they thank the LACAUT laboratory for their technical support. The authors also wish to thank the LAB AIR laboratory and its staff for their analytical support. The authors would like to thank the Academic Publishing Advisory Center (CAPA -www.capa.ufpr.br) of the Federal University of Paraná (UFPR) for assistance with English language editing.

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