Contribution of Ecosystem Services to Air Quality and Climate Change Mitigation Policies: The Case of Urban Forests in Barcelona,Spain

Mounting research highlights the contribution of ecosystem services provided by urban forests to quality of life in cities, yet these services are rarely explicitly considered in environmental policy targets. We quantify regulating services provided by urban forests and evaluate their contribution to comply with policy targets of air quality and climate change mitigation in the municipality of Barcelona, Spain. We apply the i-Tree Eco model to quantify in biophysical and monetary terms the ecosystem services “air purification,” “global climate regulation,” and the ecosystem disservice “air pollution” associated with biogenic emissions. Our results show that the contribution of urban forests regulating services to abate pollution is substantial in absolute terms, yet modest when compared to overall city levels of air pollution and GHG emissions. We conclude that in order to be effective, green infrastructure-based efforts to offset urban pollution at the municipal level have to be coordinated with territorial policies at broader spatial scales.     

Multidimensional risk analysis of antifouling biocides

In order to improve the orientation about the long-term sustainability of the use of the antifouling biocides tributyltin (TBT), copper, Irgarol® 1051, Sea-Nine? 211 and zinc pyrithione, used for the protection of fouling in sea-going ships, the risks posed to the marine biosphere due to their use are evaluated. The newly presented method of risk analysis uses release rate, spatiotemporal range, bioaccumulation, bioactivity and uncertainty as 5 dimensions of ecotoxicological risk. For each dimension, a scoring procedure is briefly described. The resulting risk profiles of the antifouling biocides show characteristics of the different substances, but also indicate where further information is required. Application of the method is proposed as a decision support in the integrated development of products, informed purchasing and for regulatory purposes.     

The analysis of free chlorine in the presence of nitrogenous organic compounds

Comparative analyses for aqueous chlorine using Standard Methods indicated that in chlorinated solutions containing nitrogenous organic compounds, none of these methods gave a reliable measurement of free available chlorine. Examination of the cyanuric acid-aqueous chlorine system showed that combined chlorine reacted as if it were free chlorine in all the Standard Methods. The implication of these studies for water and wastewater chlorination is that in waters containing nitrogenous organic compounds, N-Chloro compounds form which may result in an overestimation of the disinfecting potential of the added chlorine, when free chlorine is measured by Standard Methods.     

Work less,do less?

A reduction in working hours is being considered to tackle issues associated with ecological sustainability, social equity and enhanced life satisfaction—a so-called triple dividend. With respect to an environmental dividend, the authors analyse the time use rebound effects of reducing working time. They explore how an increase in leisure time triggers a rearrangement of time and expenditure budgets, and thus the use of resources in private households. Does it hold true that time-intensive activities replace resource-intensive consumption when people have more discretionary time at their disposal? This study on environmental issues is complemented by introducing the parameters of voluntary social engagement and individual life satisfaction as potential co-benefits of rebound effects. In order to analyse the first dividend, a mixed methods approach is adopted, enabling two models of time use rebound effects to be applied. First, semi-standardised interviews reveal that environmentally ambiguous substitutions of activities occur following a reduction in working hours. Second, estimates for Germany from national surveys on time use and expenditure show composition effects of gains in leisure time and income loss. For the latter, we estimate the marginal propensity to consume and the marginal propensity to time use. The results show that time savings due to a reduction in working time trigger relevant rebound effects in terms of resource use. However, both the qualitative and quantitative findings put the rebound effects following a reduction in working time into perspective. Time use rebound effects lead to increased voluntary social engagement and greater life satisfaction, the second and third dividends.     

Co-gasification of wood and polyethylene with the aim of CO and H2 production

This article describes the gasification of polyethylene–wood mixtures to form syngas (H₂ and CO) with the aim of feedstock recycling via direct fermentation of syngas to ethanol. The aim was to determine the effects of four process parameters on process properties that give insight into the efficiency of gasification in general, and particularly into the optimum gasification conditions for the production of ethanol by fermentation of producer gas. Gasification experiments (fluidized bed, 800°–950°C) were done under different conditions to optimize the composition of syngas suitable for fermentation purposes. The data obtained were used for statistical analysis and modeling. In this way, the effect of each parameter on the process properties was determined and the model was used to predict the optimum gasification conditions. The parameters varied during the experiment were gasification temperature, equivalence ratio, the ratio of plastic to wood in the feed, and the amount of steam added to the process. The response models obtained proved to be statistically significant in the experimental domain. The optimum gasification conditions for maximization of carbon monoxide and hydrogen production were identified. The conditions are: temperature 900°C, equivalence ratio 0.15, amount of plastic in the feed 0.11 g/g feed, and amount of steam added 0.42 g/g feed. These optimum conditions are at the edge of the present experimental domain. The maximum combined CO and H₂ efficiency was 42%, and for the maximum yield of CO and H₂ it is necessary to minimize the polyethylene content, minimize the added steam and the equivalence ratio, and maximize temperature.