Emission Inventories in Italy Regional Air Quality Management Planning

Transcription

1 Emission Inventory: Planning for the Future - Sheraton Imperial Hotel, Research Triangle Park, North Carolina - October 28-30, 1997 Emission Inventories in Italy Regional Air Quality Management Planning Rita Vaccaro, Carlo Trozzi TECHNE S.r.l. - Via N. Zabaglia, 3 - I Rome ABSTRACT The paper describes the criteria used for the realization of emissions inventories within regional air quality management plans in Italy. The criteria that have been used to classify sources in four categories (point, localized, area and linear sources) are introduced and the methodologies of estimate are discussed. Particularly are introduced the values of thresholds beyond which an industrial source has to be considered as a localized or point source. Particular emphasis will be place to road transport estimate, which will utilize data coming from regional studies of mobility and urban traffic plans. Methodologies for temporal distribution of annual emissions based on proxy variables are introduced in order to apply dispersion models. Also criteria connected with spatial distribution of emissions on 1 km x 1 km grid are evidenced, particularly the use of the official EC cartography related to land use. Finally, in the paper it is shown that a good inventory is the basis for emissions projections in the frame of air quality management plans. It is also evidenced as the definition of objectives of air quality, and of control measures, have their basis in the results of emission inventories. INTRODUCTION The paper describes the criteria used and the problems involved in the development of emissions inventories in Italy Regional Air Quality Management Planning. The criteria have been applied previously to prepare emission inventories in areas with large urban and/or industrial agglomerates (Venice, Florence, Piombino, Rossano Calabro, Roma) and now to regional emissions inventories as basic tools for air quality management plans. Several experiences of air quality management plans have been realized or are in progress (Provincia Autonoma di Trento, Regione Toscana, Provincia Autonoma di Bolzano, and Regione Liguria). Figure 1 gives a framework of geographical coverage of emission inventories realized with the described methodology. Italian legislation, through a Republic President legislative decree (no. 203, dated May 24, 1988), has delegated provincial administrations to realize air pollutant emissions inventories. A subsequent law, on Criteria for elaboration of regional air quality plan (dated May 20, 1991), has established that all the regional administrations have to draft the air quality management plan. Emission inventories are the basic instrument for the realization of air quality management plans, but at today only few regions have really absolved to these laws. According to the law, the air quality management plan is the instrument of programming, co-ordination and control of human activities with atmospheric emissions convoyed and distributed both, having as the primary aim the protection of human health and of environment. The plan is particularly devoted to the planning of interventions in areas with high risk of environmental crisis and particularly in industrial areas and in urban areas very congested. The objectives of the air quality management plan, according to the law, are the following: a) Formulate air quality management plan respecting air quality limit values established for specific pollutants and produced by industrial plants (203/88 Republic President legislative decree dated May 24, 1988); b) To develop or take into account preservation plans for specific areas in which it is necessary to limit or to prevent an increasing of air pollution coming from urban and industrial developments;

2 c) To develop or take into account environmental protection plans for specific areas in which it is necessary to assure a special environmental protection; d) To individuate areas characterized by specific needs of environmental protection and some categories of plants with regard to definition of more restrictive limits than those defined in the guidelines; e) To take into account air quality management plans developed according to law 8/28/1989 for areas with high risk of environmental crisis. The predisposition of plans involves: 1) The individuation of areas or of productive sectors, through the analysis of general characteristics of the territory and the elaboration of information available, for the evaluation of impact on population and environment. 2) The indication, in every area and/or productive or civil sector, of interventions for air quality management planning. 3) Development, setting up and audit of control instruments for the carrying out of plan and of the efficacy of the proposed interventions. EMISSIONS INVENTORIES AT LOCAL LEVEL The preparation of air pollutants emissions inventories in urban areas allows to characterize the different role played by the various emission sources and consequently represents a basic tool to define criteria for air quality management plans. An inventory may be also of great importance for planning an air qualitymonitoring network. The definition of suitable grids, inside which it is possible to report emissions also allow to point out possible hot spots, namely situations in which air quality standards are not respected. A fundamental aspect in preparing inventories is the definition of the main activities to evaluate pollutant emissions. The nomenclature used at local level follows the guidelines coming from the European Commission CORINAIR working group, which is the base of CORINAIR 1990 inventory. CORINAIR nomenclature includes about 200 activities grouped in 11 macro-sectors 1 : Public power plants, cogeneration and district heating Combustion - Commercial, Residential and Public Administration Industrial combustion Production processes Fuels extraction and distribution Solvent use Road Transport Other mobile sources Waste treatment and disposal Agriculture Nature This nomenclature may be suitably enlarged to take in account locally relevant activities. For example, some typical activities, particularly significant in the territory, have been considered such as the textile in Florence inventory and shoe industries in Venice inventory, while in Liguria and Toscana regions the shipyards activities are included. Local inventories generally refer to five main air pollutants, namely nitrogen oxides (NO 2 ), sulphur oxides (SO 2, SO 3 ), non mechanic organic compounds (NMVOC), carbon monoxide (CO) and total suspended particles (particularly PM 10 ). Regarding NMVOC the single compounds must be considered, in order to permit the aggregation into species for using dispersion photochemical models. Other pollutants, which are included in the inventories, are: Heavy metals CO 2 Ammonia

3 CRITERIA FOR THE REALIZATION OF EMISSION INVENTORIES The sources are generally splitted in four categories by: Point sources Localized sources Distributed sources Linear sources For the realization of inventories from point and localized sources it is useful to take into account the requests of authorization form industries according to Law 203/88, available in Regions and/or Provinces. In these requests the hourly average emission or the concentration of pollutants in exhausts gas and hourly gas flow are reported. From this documentation it is possible to evaluate, in a preliminary way, the emissions (expressed in kg) for single point of emission, through (1): E i = O i * g * h (1) where i = pollutant O i = hourly average emission (kg/h) g = working days for year h = working hours for day If hourly average emission is not available, it is calculated as (2): O i = P * C i * 10-6 (2) where P = hourly gas flow (Nm 3 /h) C = concentration of pollutant (µg/nm 3 ) The emissions so obtained have to be verified since: the industries can have omitted one type of information (gas flow, concentrations, hours); the declared concentrations can result more high than effective ones; the number of hours can be referred to all plant and not to single plant or specific process (Es. painting). Comparison between declared data and estimated data through standard emission factors is very important. It is necessary also to verify the completion of information through the insertion of pollutant emissions not declared by the industries, but existing. Then the emissions are calculated for the whole plant as sum of emissions of all stacks. If the total emission of one pollutant is major than a fixed threshold value (minimum pollutant amount emitted at a certain time), the plant is considered a point or localized source. Among these sources, a more specific characterization is required for point sources, the emissions of which are particularly relevant. They are characterized through the emission site coordinates, area and height of the emission point, and emissions dynamic characteristics (gas flow, outflow speed, gas temperature). For point sources, information are gathered through a questionnaire which allows to collect general data (identification, location, etc.), structural data (stacks and units characteristics) and quantitative data (pollutants concentrations at the stacks, pollutants emissions, production capacity, actual production, fuel consumption). Since the amount of emitted pollutants also depends on the operation times of each source, the questionnaires collect data about this aspect too (load diagram); these data are also useful to temporally disaggregate pollutant emissions. For localized sources, less important than point sources, information are gathered through a more simplified questionnaire with general data, pollutant emissions and actual production. The threshold definition depends, of course, on the area considered for the inventory. In some previous inventories realized (Florence, Venice, Piombino) the following thresholds have been utilized for emissions: 5 t/year for localized sources 25 t/year for point sources

4 5 MWth for power plants. More recently (inventory for Trento air quality management plan) the power thresholds have been eliminated. Figure 2 reports the graph of SO x emissions from point and localized sources for Trento inventory. In the case of the inventory for the Toscana region, activity in progress within the realization of air quality management plan, it has seemed opportune to consider the industries with emissions of one pollutant more than 25t. In fact Toscana is a very large region with many industries of small and medium level for which a collective treatment is more useful. For the realization of the emission inventory in Liguria Region, activity in progress within the realization of information system for the development of the air quality management plan, the following thresholds have been individuated: Localized sources: Point sources: 50 t/year for CO 50 kg/year for heavy metals 5 t/year for other pollutants 250 t/year for CO 250 kg/year for heavy metals 25 t/year for other pollutants The selection of more restricted thresholds comes from the particular morphology of the Region confined between the sea and the mountains with only limited area available for human activities. Regarding distributed sources a first distinction is necessary for the activities, having point origin, and emissions less than threshold adopted for localized sources. For the estimate of the emissions from these sources, the data coming from requests of authorization of industries can be utilized considering the activity, the emissions and the reference grid of the plant. In this case the emissions on municipal scale and for single activity of the classification adopted, and the values to disaggregate on a square grid mesh (1km x 1km) will be constructed. Where possible, the data so obtained will be compared and integrated with those coming from statistical sources at provincial or municipal level. For other activities (for instance, domestic solvent use and natural sources) a statistical treatment of information is necessary. These sources are evaluated on a geographical basis, inside each district or area and subsequently spatially disaggregated in thinner meshes. Area sources are characterized collecting data on suitable indicators (Es: paint consumption for painting activities, fuel consumption for combustion activities and so on) using bibliographic sources and ad hoc inquiries at qualified regional or provincial bodies. In the absence of specific indicators it is possible to use surrogate variables that, because of their great correlation with the activity to estimate, allow obtaining almost reliable results. Area sources emissions are evaluated through suitable emission factors found in the literature, such as those published by the EC CORINAIR working group or US EPA. Experimental data, eventually available at local level, may be checked to get more reliable emission factors. For some activities suitable methodologies have been developed to estimate pollutants emissions, as for harbors 2, 3, and from airports 4. Finally pollutants emissions from linear sources are obtained by splitting each line in several segments univocally defined on the geographical area. Linear sources correspond to the main communication ways (road, river, railway, seaway). Generally this category contains all the highways an all the main urban and extra-urban roads. Emissions estimate from road traffic, have been evaluated by using the SETS program 5, realized by extending and adapting at local level the methodology developed in the frame of the EC CORINAIR working group 6. Using SETS, emissions may be estimated on a single road or inside an area: hot, cold and evaporative (for gasoline vehicles) emissions are considered. Basic data are number of vehicles and total mileage by kind of vehicle (cars, light duty vehicles, heavy-duty vehicles, and motorcycles) and by fuel (diesel, gasoline ad LPG).

5 SPATIAL AND TEMPORAL DISAGGREGATION Methodologically it is of great importance to analyze separately local level and urban level. Especially for large municipalities, it is a good practice to treat the entire municipality as an urban area; the economical growth, in fact, has generated large built-up areas nearby the real urban center, areas that can be quite considered inside the town. Moreover, the municipal level seems to be the most reliable defined to estimate emissions. Inside the municipality a square grid mesh is built-up to represent pollutants emissions. The evaluation of emissions inside these meshes allows the application of diffusion models. To disaggregate pollutant emissions from the municipal level to the mesh level, the methodology of proxy variables is used. Proxy variables allow obtaining information on a certain spatial resolution assuming that it is known for larger spatial resolutions. For the distribution of emissions on municipal basis is necessary for every unknown activity at municipal level, to individuate one or more surrogates known at municipal level and then to distribute the provincial value on municipality basis. When municipal value is known, the municipal value is distributed on the square grid mesh. In this context the problem can be subdivided in two particular cases: the data, which has to be distributed, is an extensive variable, or depends on a variable proportional to level of covering of a single mesh (for example forests, the emissions from domestic sector, ); in this case the level of covering of the variable on single mesh is utilized and the municipal value is related to this level of covering; the data, which has to be distributed, is an intensive variable or depends on the presence of the activity estimated at municipal level on the single mesh; in this case the weight of the mesh on the total municipal value, obtained through the surrogate variable is utilized. In the first case, through the maps of land use, developed within the EC CORINE Land Cover, it is possible, for every typology of classification, to calculate the covering on every single mesh. The emissions on mesh k are obtained as (3): E k = Σ j Σ l Σ i l (E lj P klj / Σ k P klj ) (3) where: i = activity j = municipality k = mesh l = variable proxy E ij = total emission of activity i in the municipality j P kl = cover of proxy e on the mesh k Table 1 shows the correspondence between proxy and activity. Some activities cannot be spatially disaggregated through land use, but it is necessary to collect other data. Table 2 indicates the variables used for the disaggregation on grid. Figure 3 reports the graph of the distributed VOC emissions coming from the Trento inventory. Annual emissions are the first information used to characterize air pollutants emissions inventories. Once annual emissions have been evaluated, it is also important to obtain an estimate of their temporal distribution especially to allow the application of diffusion models to study short-time pollutants dispersion. As regards the temporal disaggregation of emissions, hourly, monthly and daily disaggregations have to be considered. Such variations generally depend on physical parameters like temperature or socials ones like working hours, production rates, power consumption and so on. In this way annual emissions may be correlated with a certain reliable group of these parameters to obtain the temporal disaggregation. For point and localized sources temporal disaggregation may be evaluated directly at the plant, through the questionnaires just defined, while for the other sources it follows the methodology below defined.

6 For all sources of less entity the subdivision is obtained through the use of corrective factors which have a similar rule of the variable proxy in the case of spatial distribution. Example of temporal proxy by activity are typical working day (of 8 hours or 16, or 24 hours depending on the activity), typical period in heating, production of wine, temperature, selling of gasoline in highway and monthly selling of gasoil. From Trento inventory, Figures 4, 5, 6 report the graphs of monthly distribution of Volatile Organic Compounds emissions, daily distribution of Carbon Monoxide emissions and hourly distribution of Volatile Organic Compounds. EMISSIONS FROM ROAD TRANSPORT The following typologies of vehicles have to be taken into consideration: passenger cars, light-duty vehicles (<3.5t), heavy-duty vehicles (>3.5t), motorcycles with cylinder capacity <50cc, motorcycles with cylinder capacity >50cc. The following fuels have to be taken into consideration: gasoline, diesel, LPG. Regarding gasoline vehicles the subdivision between the classes of cylinder capacity: cc < 1400, 1400 < cc < 2000, cc > 2000 and the subdivision based on the application of the norms of European Communities (EC): PRE ECE, ECE 15/00-01, ECE 15/02, ECE 15/03, ECE 15/04, Closed Loop. For diesel vehicles the subdivision into two classes of cylinder capacity (cc): cc < 2000, cc > 2000 is carried out. Regarding the speed, a distribution in thirteen classes to define the different typologies of driving is included. For the calculation of emissions is opportune to separate estimate from traffic for the great viability (highway and main state roads) from estimate from urban and extra-urban traffic. The estimate of emissions from traffic for highways (linear sources) is carried out with this procedure: Individuation and representation in a map of single segments through initial and final coordinates; Collecting of information on fluxes and average speed along single segments of highways of the region; Estimate of mileage along the single segments of highways of the region based on CORINAIR classification of vehicles; Collecting of the composition of vehicle park at national and regional level based on CORINAIR classification of vehicles; Computing emissions with SETS software. Regarding main extra-urban roads (linear sources): Individuation and representation in a map of single segments through initial and final coordinates Reconstruction of information related to fluxes, average speed along single segments through models for the assignment of fluxes; Estimate of mileage along single segments based on CORINAIR classification of vehicles; Estimate of emissions along single segments starting from mileage estimated previously and average speeds; Estimate of fuel consumption (along single segments and global); Computing emissions with SETS software. For the traffic other than highway and main extra-urban roads, an estimate of global area emissions is carried out based on: Composition of vehicle park at national and regional level based on CORINAIR classification of vehicles; Estimate of global mileage in region based on CORINAIR classification of vehicles; Estimate of fuel consumption and comparison with fuel distributed in region minus fuel consumption on main extra-urban roads; Computing emissions with SETS software. Regarding the estimate of mileage, data coming from study of mobility regional or provincial plans, urban traffic plans, computations on specific roads are utilized. In absence of these information, it is necessary to make a reconstruction of flows of traffic utilizing models of mobility simulation and existing measurements.

7 PROJECTIONS OF EMISSIONS, DEFINITION OF OBJECTIVES OF AIR QUALITY AND OF STRATEGIES OF REDUCTION Within the realization of air quality management plan, the projections of emissions of air pollutants for 5-15 years in absence of interventions ( do nothing scenario) are carried out with the following steps: Simulation of energy demand; Projections of relevant industrial production; Projections of vehicle park, mileage and consumption; Projections of socio-economical variables connected to activity of domestic type. Evaluation of the different technologies of emission reduction. In order to construct a do nothing scenario, it is necessary to analyze the different aspects of regional planning, in order to obtain information about the projections of activity indicators and particularly: Regional or provincial programs of development; Regional or provincial urbanistic plans; Regional or provincial and urban transport plans; Regional or provincial energy plans. Figure 8 reports the graph of the projections of NO x emissions to 2000, 2005, 2010 with reference to do nothing scenario coming from Trento inventory. Starting from do nothing scenario is possible to construct alternative scenarios introducing different measurement of emissions control. Alternative scenarios of economic and energy type (activity) and technological type (emission factors) are supplied. The join of the two scenarios supplies the emissive scenarios for the plan. The do nothing scenario is used for the comparison with the alternative scenario in order to determine, subsequently to the definition of the objectives of air quality management, possible interventions of emissions control. Figure 9 reports the graph of the projections of NO x emissions to 2000, 2005, 2010 with reference to Trento air quality management plan. CONCLUSIONS Air quality management plans are in progress in Italy. In the paper main characteristics of emissions inventories, basic instruments for the realization of the plans, are focused and discussed. REFERENCES 1. European Commission; CORINAIR Technical Annexes, Volume 1 Nomenclature and software; European Commission, DGXI, Luxembourg, EUR 12586/1EN, Trozzi, C; Vaccaro, R. Methodologies for Estimating Air Pollutant Emissions from Ships; Techne S.r:l., Via N. Zabaglia 3, Rome, Italy, 1997; Techne Report MEET RF97, pp Trozzi, C.; Vaccaro, R.; Nicolò, L. Air pollutants emissions estimates from maritime traffic in harbours: the italian harbours of Venice and Piombino, The Science of the Total Environment 1995, 169, Trozzi, C.; Vaccaro, R.; Nicolò, L.; Trobbiani, R.; Martinelli, A. AIR AIR: Estimate of Air Pollutants Emissions from Airports, In Software per l Ambiente; Patron, Eds.; Bologna, 1995 pp Trozzi, C.; Vaccaro, R.; Digiovandomenico, P.; Crocetti, S.; SETS: Estimate of Air Pollutants Emissions from Road Traffic, In Software per l Ambiente; Patron, Eds.; Bologna, 1995 pp Eggleston, H.S.; Gaudioso, D.; Lorissen, N.; Joumard, R.; Rijkeboer, R.C.; Samaras, Z.; Zierock, K.-H. Default Emission Factors from Road Traffic ; In CORINAIR Technical Annexes, Volume 2 Default Emission Factors Handbook; European Commission, DGXI, Luxembourg, EUR 12586/2EN, 1994 pp

8 Table 1. Proxy coming from land use and sources. Proxy Spatial Source 1 Urban zones CORINE Land Cover Agricultural zones CORINE Land Cover 2 3 Industrial and commercial zones CORINE Land Cover Modelled artificial zones CORINE Land Cover 1 5 Mining CORINE Land Cover Permanent crops CORINE Land Cover Arable land crops CORINE Land Cover Permanent meadows CORINE Land Cover Deciduous forests CORINE Land Cover Coniferous forests CORINE Land Cover Airports CORINE Land Cover Discharges CORINE Land Cover Table 2. Example of proxy used by activity. Activity Proxy Domestic combustion plant < 50 MWth 1 Agriculture Combustion plants <50 MWth 2 Industry Combustion plants <50 MWth 3 Bread production 1 Road paving with asphalt 4 Storage and handling of liquid fuels 3 Service stations 3 Pipelines 3 Gas distribution networks 1 Paint application: boat building 3 Paint application: construction 1 Paint application: domestic use 1 Paint application: car repairing 3 Other industrial paint application 3 Dry cleaning 1 Application of glues and adhesive 1 Domestic solvent use (other than paint application) 1 Automobiles Urban driving 1 Light duty vehicles <3.5t Urban driving 1 Heavy duty vehicles <3.5t Urban driving 1 Motorcycles <50 cm3 1 Motorcycles >50 cm3 Urban roads 1 Motor gasoline Evaporative emissions 1 Off roads vehicles and machinery Agriculture 2 Off roads vehicles and machinery Industry 3 Airports 11 Discharges 12 Permanent crops with fertilizers 6 Arable land crops with fertilizers 7 Meadows with fertilizers 8 Stubble burning 6 Manure management 2 Deciduous forests non-isoprene emitters 9 Coniferous forests 10

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10 Figure 1 Emission inventory and air quality management plan in Italy (grey areas). Figure 2. Trento sulphur oxides point sources emissions (kg/year).

11 Figure 3. Trento Volatile Organic Compounds diffuse emissions on square grid mesh (kg/km/year). Figure 4. Trento Monthly Distribution of Volatile Organic Compounds emissions (kg). 4000,0 3000,0 2000,0 1000,0 0,0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Figure 5. Trento Daily Distribution of Carbon Monoxide emissions (kg). 230,0 220,0 210,0 200,0 190,0 180,0 170,0 Mon Tue Wed Thu Fri Sat Sun

12 Figure 6. Trento Hourly Distribution of Volatile Organic Compounds (kg). 5,0 4,0 3,0 2,0 1,0 0, Figure 7. Nitrogen oxides linear sources emissions (kg/km).

13 Figure 8. Trento NO x emissions projections (Mg) Cent Min. Max Figure 9. Trento NO x emissions projections in plan scenario (Mg) , , , ,0 5000,0 0, MP# - Point sources MT4 - Car pooling MT2 - Heavy-duty road transp. reduct. MT1 - EC Auto/Oil program MD1-4+MT3+MT6 - Other reductions Reduced Emissions