GHG EMISSIONS ESTIMATION OVER A MEDITERRANEAN CITY THROUGH DIRECT MEASUREMENTS AND INVENTORY APPROACH

Serena Marras1,2, Costantino Sirca1,2, Veronica Bellucco1, Laura Sanna3, Roberto Ferrara3, Pierpaolo Duce3, Donatella Spano1,2

1. DIPNET-Department of Science for Nature and Environmental Resources, University of Sassari, Italy, [email protected]; 2. CMCC, Euro-Mediterranean Centre on Climate Change, Sassari, Italy; 3. CNR-IBIMET, Consiglio Nazionale delle Ricerche, Sassari, Italy

Population: 127,625 (2014) THE CITY OF SASSARI Pop. density: 237 people/km2 Municipality Area: 546 km2 Urbanized area: 2.24 km2 (4%) Arable and horticulture crops lands: (56%) Altitude: 225 m asl Mean annual temperature: 16.2 °C (30-yr) Annual precipitation: 567 mm (30-yr)

Lat. 40° 43’ 36″N Long. 8° 33’ 33″E Sassari is the second town in Sardinia, a large island located in the center of the Mediterranean Basin (Fig. 1). Google Earth Fig. 1. Sassari location in the North As part of a Regional Project, a research activity has been carried out with the general aim to quantify urban fluxes of Sardinia island (Italy). and identify the main GHG emissions sources. A combined methodology is used for this purpose. N 1. DIRECT CO MEASUREMENTS 600 2 500 NW 400 NE An Eddy Covariance tower was set up, in April 2015, in the Sassari city center to directly measure CO2, water, and 300 energy fluxes. Gill-HS sonic anemometer and Li-7200 Enclosed gas analyser were used for this purpose. 200 100 Meteorological and radiometric stations were also installed (Fig. 2). W 0 E

-2 -1 CO2 flux ranged from -12 to 63 μmol m s with an average value of 4.2 μmol m-2 s-1 (Fig. 4a). Emission peaks are clearly related to the rush SW SE hours during the working days (Fig. 4b). S Air temperature measurements revealed that temperature was above 25 °C for 14 days (i.e. for about half of the measurements period). Fig. 3. Wind-rose for the city of Sassari, Italy. Mistral (NW) and Libeccio (W-SW) are the main CO flux (b) Weekend and holidays prevailing winds. (a) 2 Work days 12 • Mean building height = 13 m All days 80 )

1 10 - s 2

- Table 1. Measured values of air • # Buildings = 3108 1 60

- 8 s 2

- temperature (Tair), precipitation 40 6

• Measurement height = 24 m mol m

μ 4 (Pcp), wind speed (WS), and relative

mol m 20 • Zero plane displacem. = 8.7 m μ 2 humidity (RH). flux ( 2 0 0 • Roughness lenght = 1.3 m CO Mean Maximum Minimum Total -20 -2 Tair (°C) 19.2 33 9.9 - Fig. 2. Eddy Covariance tower on the roof of the Policy 118 122 126 130 134 138 142 146 150 154 158 0:00 3:00 6:00 9:00 12:00 15:00 18:00 21:00 Pcp (mm) - 5 - 14.2 building in the city center. DOY Hours DOY WS (km 8.3 25.9 - - h-1) Fig. 4. Half-hourly CO flux measurements (a) and mean diurnal cycle for both working days 2 RH (%) 57.6 98.9 7.9 - and weekend or holiday periods (b). 2. GHG INVENTORY A spatial and temporal high resolution GHG emissions inventory for the urban area of Sassari is currently The first result of the under construction, in line with European and international standard protocols, to establish a baseline for Inventory approach was the tracking emission trends. classification of the urban emissions, catalogued by GHG, productive activity and emissive source (baseline year 2010) (Table 2).

Table 2. Inventory categories of GHG emissions in the town of Sassari, Italy.

Stationary Units Mobile Units Waste Residential building On-Road transportation Solid waste disposal Building types (year, heating, etc.) Private cars Landfilled municipal solid waste (MSW) Commercial Facilities Pubblic cars Special wastes Store Centers Light trucks Biological treatment of waste Shops Heavy trucks Composting Institutional Facilities Motorcycles Wastewater treatment and discharge Hospital Mopeds Anaerobic digestion Municipal buildins Motorhomes Aerobically treatment County buildings ATP Bus IPPU Regional buildings ARST Bus Industrial Processes and Product Uses Public Light Railways Calcrete uses Bank buildings Trains and Metro Consumption of cement, lime and soda ash Energy generation (undirect Aviation Chemical production emissions) Helicopters Consumption of petroleum products Grid-supplied electricity Off-Road Limestone uses Energy use Lubrificants uses eQUEST GIS building Assessor’s Building Energy Use in Industrial Activities Go-kart intensity footprints Building height Bakery Brush-cutters Bitume, road oil and other petroleum diluents simulation -2 -1 parcel data floor number kWh m time Smiths Tractors Solvents (kerosene and other aromatics) Construction equipments Paraffin waxes Simulation Nitrous oxide Calibration Landscape equipments inputs Nonelectric energy consumption (building CO2 emissions and country level) at monthly scale at country level Building prototype REFERENCES Survey data - C40 Cities Climate Leadership Group, ICLEI Local Governments for Sustainability, 2012 - Global protocol for CO emissions at building 2 community-scale greenhouse gas emissions (GPC) Pilot Version 1.0 – May 2012: pp 14. Hestia approach used for downscaling GHG estimation level and monthly scale to individual building scale and at monthly time scale - Gurney et al – Quantification of fossil fuel CO2 emissions on the building/street scale for a large U.S. City. Environment Science & Technology, 46: 12194-12202

LEGGE REGIONALE 7 AGOSTO 2007, N.7: "PROMOZIONE DELLA RICERCA SCIENTIFICA E DELL'INNOVAZIONE TECNOLOGICA IN SARDEGNA”