Spatial Analysis of Environmental Impacts Linked to Changes in Urban Mobility Patterns during COVID-19: Lessons Learned from the Cartagena Case Study

The impact of the pandemic caused by COVID-19 on urban pollution in our cities is a proven fact, although its mechanisms are not known in great detail. The change in urban mobility patterns due to the restrictions imposed on the population during lockdown is a phenomenon that can be parameterized and studied from the perspective of spatial analysis. This study proposes an analysis of the guiding parameters of these changes from the perspective of spatial analysis. To do so, the case study of the city of Cartagena, a medium-sized city in Spain, has been analyzed throughout the period of mobility restrictions due to COVID-19. By means of a geostatistical analysis, changes in urban mobility patterns and the modal distribution of transport have been correlated with the evolution of environmental air quality indicators in the city. The results show that despite the positive effect of the pandemic in its beginnings on the environmental impact of urban mobility, the changes generated in the behavior patterns of current mobility users favor the most polluting modes of travel in cities.

Differential Fatty Acids and Stress Biomarkers Responses in Native (Carcinus Aestuarii) and Invasive (Portunus Segnis) Crabs Exposed to Environmental Pollution

The present work aims to determine and compare the tolerance to different stress environmental conditions in two crabs’ species the native Carcinus aestuarii and the invasive Portunus segnis. In this study, C.aestuarii appeared more intolerant to environmental stressor as shown by the important changes occurred on the proximate, fatty acids and their essential compounds comparing to P.segnis. Our results revealed accumulation of metallic trace elements, macromolecular damages and antioxidant defense systems perturbations mostly in C.aesuarii gills and muscles than P.segnis, thus highlighting the importance of a multi-markers approach to assess the urban pollution in coastal ecosystems. According to this study, fatty acid profiles and oxidative stress biomarker examination of both crabs indicate that the different environmental stresses significantly influence the tolerance of C.aestuarii compared to the invasive P.segnis which may provide physiological advantages for the achievement of their invasion in novel ecosystems.

Evaluation of effective factors on air pollution using optimized cellular automata: A case study of Tehran

Vehicles and traffic congestion have been known as the main reasons for air pollution in urban areas, and Cellular Automata (CA) holds a great promise for predicting this hazard. Urban air pollution is a complex phenomenon and many factors involve in its distribution and diffusion. In this paper, the traffic map was used as the source of the air pollutant. Also, the prediction of urban pollution has been done using different data sources such as green space, buildings, wind direction and speed. The coefficient of these factors got estimated with Genetic Algorithm, and a comparison between different modes of the model got done. With considering the effect of these factors an accuracy of 58.4% was obtained.

Perceptions of Urban Pollution of River Dependent Rural Communities and Their Impact: A Case Study in Bangladesh

This study considers the Old Brahmaputra River, Bangladesh, as a case study regarding community perceptions on urban pollution and its impact on rural communities. In doing so, in-depth individual interviews (n = 195), key informant interviews (n = 7), and focus group discussions (n = 7) were conducted by emphasizing different perspectives on urban pollution and its effects on people related to losses of fisheries resources, agricultural production, human health, and livelihood transformation. The findings illustrate that poor urban solid waste management and direct sewage discharge degrade rivers daily. The most vulnerable rural communities are directly dependent upon the river, including fishermen, farmers, and boatmen. Specific measures such as an effluent treatment plant should be established near the river, and households and commercial drains should be cut off from the direct connection with the river. Alternative income-generating activities for the stakeholders are suggested to safeguard the river from urban pollution and the wellbeing of the stakeholders.

Distribution and Origin of Major, Trace and Rare Earth Elements in Wild Edible Mushrooms: Urban vs. Forest Areas

This paper investigates the composition of major, trace, and rare earth elements in 15 different species of wild edible mushrooms and the possible effect of urban pollution on elemental uptake. The collected mushrooms include different species from the green areas of the city, exposed to urban pollution, and from the forests, with limited anthropogenic influence. Through a comprehensive approach that included the analysis of 46 elements, an attempt was made to expand knowledge about element uptake by mushroom fruiting bodies. The results showed a wide variability in the composition of mushrooms, suggesting a number of factors influencing their element uptake capacity. The data obtained do not indicate significant exposure to anthropogenic influences, regardless of sampling location. While major elements’ levels appear to be influenced more by species-specific affinities, this is not true for trace elements, whose levels presumably reflect the geochemical characteristics of the sampling site. However, the risk assessment showed that consumption of excessive amounts of the mushrooms studied, both from urban areas and from forests, may have adverse health effects.

Isotopic signatures of methane emissions from tropical fires, agriculture and wetlands: the MOYA and ZWAMPS flights

We report methane isotopologue data from aircraft and ground measurements in Africa and South America. Aircraft campaigns sampled strong methane fluxes over tropical papyrus wetlands in the Nile, Congo and Zambezi basins, herbaceous wetlands in Bolivian southern Amazonia, and over fires in African woodland, cropland and savannah grassland. Measured methane δ 13 C CH 4 isotopic signatures were in the range −55 to −49‰ for emissions from equatorial Nile wetlands and agricultural areas, but widely −60 ± 1‰ from Upper Congo and Zambezi wetlands. Very similar δ 13 C CH 4 signatures were measured over the Amazonian wetlands of NE Bolivia (around −59‰) and the overall δ 13 C CH 4 signature from outer tropical wetlands in the southern Upper Congo and Upper Amazon drainage plotted together was −59 ± 2‰. These results were more negative than expected. For African cattle, δ 13 C CH 4 values were around −60 to −50‰. Isotopic ratios in methane emitted by tropical fires depended on the C3 : C4 ratio of the biomass fuel. In smoke from tropical C3 dry forest fires in Senegal, δ 13 C CH 4 values were around −28‰. By contrast, African C4 tropical grass fire δ 13 C CH 4 values were −16 to −12‰. Methane from urban landfills in Zambia and Zimbabwe, which have frequent waste fires, had δ 13 C CH 4 around −37 to −36‰. These new isotopic values help improve isotopic constraints on global methane budget models because atmospheric δ 13 C CH 4 values predicted by global atmospheric models are highly sensitive to the δ 13 C CH 4 isotopic signatures applied to tropical wetland emissions. Field and aircraft campaigns also observed widespread regional smoke pollution over Africa, in both the wet and dry seasons, and large urban pollution plumes. The work highlights the need to understand tropical greenhouse gas emissions in order to meet the goals of the UNFCCC Paris Agreement, and to help reduce air pollution over wide regions of Africa. This article is part of a discussion meeting issue 'Rising methane: is warming feeding warming? (part 2)'.

Diurnal variability of stratospheric column NO₂ measured using direct solar and lunar spectra over Table Mountain, California (34.38° N)

A full diurnal measurement of stratospheric column NO2 has been made over the Jet Propulsion Laboratory's Table Mountain Facility (TMF) located in the mountains above Los Angeles, California, USA (2.286 km above mean sea level, 34.38∘ N, 117.68∘ W). During a representative week in October 2018, a grating spectrometer measured the telluric NO2 absorptions in direct solar and lunar spectra. The stratospheric column NO2 is retrieved using a modified minimum-amount Langley extrapolation, which enables us to accurately treat the non-constant NO2 diurnal cycle abundance and the effects of tropospheric pollution near the measurement site. The measured 24 h cycle of stratospheric column NO2 on clean days agrees with a 1-D photochemical model calculation, including the monotonic changes during daytime and nighttime due to the exchange with the N2O5 reservoir and the abrupt changes at sunrise and sunset due to the activation or deactivation of the NO2 photodissociation. The observed daytime NO2 increasing rate is (1.34±0.24)×1014 cm−2 h−1. The observed NO2 in one of the afternoons during the measurement period was much higher than the model simulation, implying the influence of urban pollution from nearby counties. A 24 h back-trajectory analysis shows that the wind first came from inland in the northeast and reached southern Los Angeles before it turned northeast and finally arrived at TMF, allowing it to pick up pollutants from Riverside County, Orange County, and downtown Los Angeles.