Buildings have become a key source of greenhouse gas (GHG) emissions due to the consumption of primary energy, especially when used to achieve thermal comfort conditions. In addition, buildings play a key role for adapting societies to climate change by achieving more energy efficiency. Therefore, buildings have become a key sector to tackle climate change at the local level. However, public decision-makers do not have tools with enough spatial resolution to prioritise and focus the available resources and efforts in an efficient manner. The objective of the research is to develop an innovative methodology based on a geographic information system (GIS) for mapping primary energy consumption and GHG emissions in buildings in cities according to energy efficiency certificates. The developed methodology has been tested in a representative medium-sized city in Spain, obtaining an accurate analysis that shows 32,000 t of CO₂ emissions due to primary energy consumption of 140 GWh in residential buildings with high spatial resolution at single building level. The obtained results demonstrate that the majority of residential buildings have low levels of energy efficiency and emit an average of 45 kg CO₂/m². Compared to the national average in Spain, this obtained value is on the average, while it is slightly better at the regional level. Furthermore, the results obtained demonstrate that the developed methodology is able to directly identify city districts with highest potential for improving energy efficiency and reducing GHG emissions. Additionally, a data model adapted to the INSPIRE regulation has been developed in order to ensure interoperability and European-wide application. All these results have allowed the local authorities to better define local strategies towards a low-carbon economy and energy transition. In conclusion, public decision-makers will be supported with an innovative and user-friendly GIS-based methodology to better define local strategies towards a low-carbon economy and energy transition in a more efficient and transparent way based on metrics of high spatial resolution and accuracy.

Indoor air quality is a characteristic that depends on air pollutants inside a building and that can be affected by different ventilation strategies. There is strong evidence linking poor indoor air quality (IAQ) and harmful health effects, especially on vulnerable collectives, such as children in schools. Due to this concern, this work aims to provide guidance on the design of highly efficient ventilation strategies to improve the air quality of schools’ classrooms. For this, IAQ monitoring has been carried out in eight educational in real conditions centres using CO₂ concentration as an IAQ indicator. Variables such as the presence of students and their number, activity developed in the classroom and ventilation strategy used together with break time duration have been also recorded to analyse their influence on CO₂ concentration levels. Concluding results have allowed us to determine the maximum number of students allowed in a closed room to maintain CO₂ levels at normal concentrations and the time needed to reduce these CO₂ levels depending on the ventilation strategy adopted. Moreover, it has been discussed how surrounding school conditions (pollution or noise) and the building isolation are impacting the final IAQ in the classrooms studied.

Due to a continuous abandonment of marginal agricultural land, Mediterranean pine forests are growing both in biomass stock and area but remain mainly unmanaged. Pinus halepensis is one of the main pioneer species with strong expansion throughout the Mediterranean basin. In mature forests and pole stands, selective thinnings aimed to eliminate dominated and dead trees are necessary to improve the resilience and persistence of these forest ecosystems. Bioenergy market provides an opportunity to mobilise this woody material, helping to prevent and reduce wildfires in a context of climate change and energy transition. Despite the existing expertise on wood harvesting, there is a lack of practical knowledge about cost-effective methods for bioenergy use of selective thinnings in such forests. The objective of this study was to compare thinning harvesting methods in representative 63-year-old Pinus halepensis afforestation in pole stage for bioenergy uses, following the silvicultural treatments defined in the Spanish forest management plan. Time studies were performed over six representative plots in Navalón (Spain). Treatments included three plots with the traditional stem wood method combined with the logging of forest residues (integrated system), and three plots with the whole tree chipping (whole tree system). Time, productivity and fuel consumption were recorded for both systems. A woodchip quality assessment of each assortment was performed in the laboratory according to European standards. The results obtained demonstrated that time consumption and productivity were similar between the integrated harvesting system and the whole tree system. Regarding the total energy balance, it should be noted that both systems produce woodchips that contain over ten times more energy than that required to mobilise and process the obtained biomass. Fuel consumption, costs and degree of damage were slightly higher in the whole tree system due to the more intensive forwarding operation. The two assortments of woodchips in the integrated system had a higher (chipped log material) and lower quality (chipped crown material) than whole tree woodchips. In conclusion, integrated harvesting is a better option to diminish fuel consumption, cost and environmental impact, and also to obtain better quality woodchips for the production of added value biofuels (pellets).

During the period of the COVID-19 pandemic, the air quality reached the best levels to be recorded in large cities in Spain. To analyze and demonstrate this improvement in air quality levels, the evolution of the average nitrogen dioxide (NO₂) levels in 78 Spanish cities with more than 50,000 inhabitants during the pre-COVID-19 years (2017–2019), the period of the COVID-19 lockdown, and the post-COVID-19 year (2021) was analyzed. The results show an improvement in the air quality in most of the cities analyzed for 2020 due to the COVID-19 restrictions. In addition, in 2021, without the COVID-19 restrictions, the air quality levels of the largest cities in Spain showed important improvements in terms of NO₂ concentration compared to the levels in the pre-COVID-19 years (2017–2019). Nevertheless, in 2021, only 11 cities were below the average annual limit of 10 µg/m³ NO₂ established by the World Health Organization (WHO). In addition, no cities with more than 500,000 inhabitants achieved NO₂ levels below the WHO limit. Finally, a detailed monthly analysis indicated that the pre-COVID-19 levels were reached again during the last months of the monitored period.