Air quality improvements from a transport modal change in the São Paulo megacity.

Air quality and urban mobility are complex socioenvironmental issues faced by megacities, particularly those in the Global South. Investments in efficient and inclusive public transport networks, as well as encouraging active transport modals, can mitigate both traffic congestion and air pollution, leading to improved quality of life. Few studies have integrated the potential effects of a well-developed rail network in influencing modal choice - from motorised to active transport - and their impacts on pollutant emission and air quality through dynamic air quality models. In the megacity of São Paulo, the expansion of the subway system has not achieved the planned targets, as intended by state government plans. This induces the question "What would have happened to air pollution if planned stations had been properly implemented?" which this paper aims to answer, through the increased adoption of cycling or walking to and from railway stations. We applied the WRF-Chem air quality model to model the effects of railway development in a megacity, focusing on criteria pollutants. Results show that the more investments there are in public transport, by expanding the metro system, the more expressive are the decreases in air pollution, and the farther these benefits spread out spatially. More intense reductions in pollutant concentrations are predicted to occur near the new stations' buffers, but citizens living far from the metro stations will also benefit from these improvements. Additionally, modal change from car to walking/cycling and subway in all trips within a radius of 1.3 km centered in existing and planned stations is expected to result in a decrease of 11.7 % in CO2eq vehicular emissions. Therefore, improvements in public transportation could help improving environmental and social justice, leading to better air quality and transport accessibility, decreasing public health problems and costs, while helping cities reach their GEE emissions reduction targets.

Bibliometric analysis of Advanced Oxidation Processes studies with a focus on Life Cycle Assessment and Costs.

Advanced oxidation processes (AOPs) are wastewater treatment technologies that stand out for their ability to degrade Contaminants of Emerging Concern (CECs). The literature has extensively investigated these removal processes for different aqueous matrices. Once technically mature, some of these systems have become accredited to be applied on a large scale, and therefore, their systemic performances in the environmental and cost spheres have also become essential requirements. This study proposed corroborating this trend, analyzing the available literature on the subject to verify how experts in the AOP area investigated this integration during 2015-2023. For this purpose, a sample of publications was treated by applying the Systematic Review (SR) methodology. This resulted in an extract of 83 studies that adopted life-cycle logic to estimate environmental impacts and process costs or evaluated them as complementary to the technical dimension of each treatment technology. This analysis found that both dimensions can be used for selecting or sizing AOPs at the design scale. However, the appropriate choice of the impact categories for the environmental assessment and establishing a methodology for cost analysis can make the approach still more effective. In addition, a staggering number of processes would broaden the reality and applicability of the estimates, and adopting multicriteria analysis methodologies could address essential aspects of decision-making processes during the design of the arrangements. By meeting the original purposes, the study broadened the requirements for designing AOPs and disseminating their use in mitigating the discharge of CECs.

Alternative fuel technologies emissions for road heavy-duty trucks: a review.

Many alternative fuel technologies have been studied for the transport sector to increase its sustainability while reducing costs, greenhouse gases (GHG), and air pollution emissions. Nevertheless, conventional diesel is still the predominant fuel for heavy-duty trucks. Road freight transport consumes 25% of the world's energy and is responsible for emissions with local health impacts and the global greenhouse effect. In this context, this paper reviewed items from 2015 to 2020 to analyze the technologies available for the road freight transport regarding pollutant and GHG emissions. Results are presented in two parts: first quantitatively, quantitative data was extracted from reviewed papers and statistically treated and, second, qualitatively through a comparative chart, which shows the impact on air pollutants from the use of a different type of fuels. In general, papers are mostly concerned with particulate matter (PM), carbon monoxide (CO), nitrogen oxides (NOx), and hydrocarbons (HC) emissions due to its impact on public health, with a low number of papers covering GHG emissions. The trade-off between different fuels and how this process can impact emissions, sometimes increasing or decreasing specific pollutants, is discussed. According to the analyzed papers, the main characteristics that affect the pollutant emissions are, in general, the fuel oxygen content and the combustion chamber temperature.

Costs and emissions assessment of a Blue Corridor in a Brazilian reality: The use of liquefied natural gas in the transport sector.

Technical, economic, social and environmental conditions are turning natural gas into a feasible solution for sustainable transportation systems in the State of São Paulo (Brazil). Blue Corridors are routes that aim to enable the use of liquefied natural gas (LNG) for heavy vehicles as a substitute to Diesel oil. Therefore, this work proposes four scenarios for a Blue Corridor in the State of São Paulo and analyzes its environmental and economic impacts. The results are presented in cartographical figures and show that LNG costs up to 40% less than diesel, while reducing CO2 equivalent emissions by up to 5.2%. Particulate matter (PM) emissions are reduced by 88%, nitrogen oxides (NOx) by 75% and hydrocarbon emissions are eliminated. However, despite the economic and environmental advantages presented in the results of this study, LNG still faces regulatory barriers that must be addressed in order to allow its widespread use in the transportation sector.