• Energy Research

Abstract This study presents a reanalysis of ozone (O3) exposure experiments performed on deciduous broadleaf oak species in the Mediterranean region and a proposal of critical levels to improve the O3 risk assessment in this area for these widely distributed forest species. Two experiments performed in Spain and Italy were considered, and the following 3 oak species were studied: Quercus pyrenaica, Q. faginea and Q. robur. All the experiments were performed with irrigated potted seedlings growing in Open-Top Chambers exposed to different O3 levels (with charcoal-filtered air as the control treatment) for two consecutive growing seasons. The Phytotoxic Ozone Dose above an instantaneous threshold of 1 nmol O3 m−2 s−1 (POD1) was calculated by applying a Jarvis type model for the estimation of the stomatal conductance (gs), and by adopting a big-leaf resistive scheme to account for the O3 deposition on the vegetation. Two parameterisations were used for the gs multiplicative model: one species-specific based on the “local” gs measurements performed during each experiment, and the other “generic” based on the “Deciduous Mediterranean broadleaf” parameterisation described in the Manual on Methodologies and Criteria for Mapping Critical Loads and Levels and Air Pollution Effects, Risks and Trends of the UN/ECE (CLRTAP, 2015). The two different parameterisations were used to derive dose-response functions and ozone critical levels for the biomass loss of the deciduous oak species. The dose-response functions for roots and total biomass were statistically significant, with both the parameterisations tested (p

Capitolo introdduttivo all'area di studio scelta nelle Alpi meridionali come focus per l'ozono e il rischio incendi. Presenta le propiezioni climatiche nell'arfea fino alla fine del secolo.

To derive O3 dose-response relationships (DRR) for five European forest trees species and broadleaf deciduous and needleleaf tree plant functional types (PFTs), phytotoxic O3 doses (PODy) were related to biomass reductions. PODy was calculated using a stomatal flux model with a range of cut-off thresholds (y) indicative of varying detoxification capacities. Linear regression analysis showed that DRR for PFT and individual tree species differed in their robustness. A simplified parameterisation of the flux model was tested and showed that for most non-Mediterranean tree species, this simplified model led to similarly robust DRR as compared to a species- and climate region-specific parameterisation. Experimentally induced soil water stress was not found to substantially reduce PODy, mainly due to the short duration of soil water stress periods. This study validates the stomatal O3 flux concept and represents a step forward in predicting O3 damage to forests in a spatially and temporally varying climate.

Abstract An open-top chamber experiment has been carried out at the facilities of Curno (North Italy), in June–August 2009, to assess the response to ozone in two poplar clones Populus maximowiczii Henry × P. berolinensis Dippel (Oxford clone, OX), and Populus nigra “Jean Pourtet” (JP) in concomitance of severe drought events. Three different water regimes were applied: W – Well Watered Control: field capacity; D1 – Drought Treatment 1: field capacity until begin July, then reduced water availability (plants were then subjected to severe drought events); D2 – Drought Treatment 2: constant water shortage (plants were then subjected to severe drought events). Leaf water potential, gas exchange and chlorophyll fluorescence (JIP-test) were assessed every 2 weeks; growth parameters and stable isotope composition ( δ 13 C and δ 18 O) were measured at the end of the experiment. The main results were: (i) drought, but not ozone, reduced photosynthesis and growth and increased δ 13 C; (ii) the two clones showed different strategies to cope with ozone stress: JP shed the damaged leaves, whereas OX maintained their leaves ozone provoked the loss of leaves in W plants of the JP clone; (iii) in the D1 plants the response to drought provokes an additional effects with the effect of ozone absorbed before the severe drought events; (iv) D2 plants did not respond to ozone until the last event, when a clear synergistic effect between the two stressors was observed. We conclude that ozone had different effects in relation to the way the drought stress was applied. These results are discussed for their ecological consequence on vegetation in field conditions.

Abstract This study focuses on the environmental impact assessment through Life Cycle Analysis (LCA) of two innovative 10 kW pellet boilers. In particular, the second boiler represents a technological evolution of the first one developed to improve its performance in terms of efficiency and environmental impact. For both boilers, emission factors measured during laboratory tests (full load tests and specific load cycle tests representative of real life boiler operation) have been used as input data in the life cycle analysis. The SimaPro software (v.8.0.4.30) was used for the LCA and the ReCiPe Midpoint method (European version H) was chosen to assess the environmental impact of all boilers (according to LCA ISO standards). In addition, the ReCiPe Endpoint method was used to compare the final results of all 5 boilers with literature data. The pelletisation process represented the most relevant share of the overall environmental impact followed by the operational phase, the manufacturing phase and the disposal phase. A sensitivity analysis performed on the most efficient pellet boiler evidenced the variation of the boiler’s environmental impact as a function of PM10 and NO X emission factors with respect to emission factors monitored during boiler full load operation. Moreover, the reduction of the boiler’s weight and the adoption of new electronic components led to a consistent reduction (−18%) of its environmental impact with respect to the previous technology. A second LCA has been carried on for a 15 kW oil boiler, a 15 kW natural gas boiler and a 15 kW pellet boiler, representative of the state of the art of EU technology, to finally compare all LCA results. Results showed the environmental impact reduction of BW10 and BW10 2 pellet boilers with respect to fossil fuelled boilers mainly due to their reduced impact on CC (reductions by 86–90% and 88–91% with respect to the NG and oil boilers respectively), NLT (reductions by 77–79% and 86–87% with respect to the NG and oil boilers respectively) and FD (reductions by 89–92% and 90–93% with respect to the NG and oil boilers respectively) ReCiPe Midpoint subcategories.

The present study investigated the response to ozone (O3) of two cultivars (cv.'Romana' and cv. 'Canasta') of irrigated lettuce grown in an open-top chamber (OTC) experiment in Mediterranean conditions. Two different levels of O3 were applied, ambient O3 in non-filtered OTCs (NF-OTCs) and -40% of ambient O3 in charcoal-filtered OTCs (CF-OTCs), during four consecutive growing cycles. At the end of each growing cycle, the marketable yield (fresh biomass) was assessed while during the growing periods, measurements of the stomatal conductance at leaf level were performed and used to define a stomatal conductance model for calculation of the phytotoxic ozone dose (POD) absorbed by the plants.Results showed that O3 caused statistically significant yield reductions in the first and in the last growing cycle. In general, the marketable yield of the NF-OTC plants was always lower than the CF-OTC plants for both cultivars, with mean reductions of -18.5 and -14.5% for 'Romana' and 'Canasta', respectively. On the contrary, there was no statistically significant difference in marketable yield due to the cultivar factor or to the interaction between O3 and cultivar in any of the growing cycle performed.Dose-response relationships for the marketable relative yield based on the POD values were calculated according to different flux threshold values (Y). The best regression fit was obtained using an instantaneous flux threshold of 6 nmol O3 m-2 s-1 (POD6); the same value was obtained also for other crops. According to the generic lettuce dose-response relationship, an O3 critical level of 1 mmol O3 m-2 of POD6 for a 15% of marketable yield loss was found.

This paper reports the results of an Open-Top Chambers experiment on the responses of two durum wheat cultivars (Neodur and Virgilio) exposed to two different levels of ozone (charcoal-filtered air and ozone-enriched air) and irrigation water salinity (tap water as control and a 75 mM NaCl solution once a week). The stomatal conductance of the flag leaves was measured on four dates during May. Flag leaf samples were collected to detect ozone visible leaf injuries. At the end of the growing season, the yield/biomass and grain quality parameters were assessed. Saline irrigation caused significant reductions in gs, yield and grain quality in Neodur, while Virgilio was more tolerant. The yield response to ozone was almost negligible, with Virgilio, despite the higher susceptibility to visible leaf injuries, being more productive than Neodur. The responses to the combined stress were not consistent, with the main tendencies undoubtedly driven by the saline irrigation factor.