Evaluation of Port of Casablanca Operations on Air Quality in the Greater Metropolitan Area of Casablanca, Morocco

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1 Evaluation of Port of Casablanca Operations on Air Quality in the Greater Metropolitan Area of Casablanca, Morocco Tony RIZK (1), El-Hadj JABRY (2), Mohamed BENABDENNBI (3) (1) Tony Rizk, PhD, PE. Cedars Engineering Solutions. 634 Paseo de la Playa, Redondo Beach, CA 90277, Phone: (310) , (2) El-Hadj JABRY, Directeur CEREP, Laboratoire Public d Essais et d Etudes. Oukacha, No 1, Rue 1, Bd. Moulay Slimane, Casablanca, MAROC (3) Mohamed BENABDENNBI, Directeur du Developpement, Office Developpement et Exploitation des Ports. 175, Bd. Zerktouni, Casablanca, MAROC ABSTRACT In the context of a regional environmental mitigation program of the great metropolitan Casablanca, Morocco, the authors of this paper conducted an evaluation of the air emissions from the operations at the Port of Casablanca. The principal exports include phosphates, minerals, fruits and vegetables. The principal imports include coal, grains, and sugar. Particulate emissions are generated in the transfer of these materials and goods from and to ships. This paper describes an approach to estimate the emissions form the port. This approach includes particulate emissions monitoring and inverse modeling with rigorous data quality assurance and quality control. This resulted in an estimate of 252 tonnes/year of particulate emissions from the port. This information will be integrated into a city wide air quality monitoring and forecasting program. 1. PROBLEM DESCRIPTION The air quality of the greater metropolitan region of Casablanca is impacted by atmospheric emissions from electric generation stations, refineries, chemical and manufacturing industries, transportation, and port operations. In consensus, the major refinery of the region (SAMIR), the national meteorological directorate (DMN), the national electrical office (ONE), and the port development and exploitation office (ODEP), with the support of the Morocco Ministry of the environment, formed an regional council for the protection of the environmental. The council directed the public laboratory of measurements and studies (LPEE), a division of the ministry of public works to quantify the atmospheric emissions from these sources and to develop a regional air quality forecasting program. The LPEE and the council employed Cedars Engineering Solutions to assist in this endeavor. The objective will be achieved in phases. The first phase consisted of an emissions inventory of the principal fixed and mobile sources in the region. This phase was completed at the end of Given the unique aspects of operation of the port of Casablanca, the second phase in this program consisted of monitoring and inverse modeling of the emissions from the port. This phase was completed in the summer of The third phase consists of the development of a regional modeling and monitoring program leading to air quality forecasting. This phase is expected to begin in the summer of The port of Casablanca is the located on the Atlantic Ocean in the center of the country. As shown in Figure 1, the port includes three (3) industrial loading and unloading piers. The principal exports include phosphates and fruits and vegetables. The principal imports include 1

2 coal, grains, and sugar. Pier C is dedicated to export phosphates. Phosphates arrive at the port on trains, from which the product is transferred by a conveyor system to boats on dock. Piers A and B are used for import and export of all other goods and materials. The loading and unloading at piers A and B is commonly achieved with over-head cranes equipped with buckets or mobile forklifts. Significant particulate fugitive emissions are generated in all of these activities. These emissions can be observed from a distance and from the air. 2. METHODOLOGY The approach used in the determination of the emissions of the port included particulate sampling, inverse modeling of the emissions, and mass estimate of these emissions. Inverse modeling is often a complex task. The results can be unreliable due to lack of uniqueness and large uncertainty in the data acquisition. Thus, at the onset of this effort, The LPEE and Cedars developed and implemented a stringent quality assurance and quality control program to minimize errors and sources of uncertainty. Four (4) continuous high volume particulate samplers were stationed in close proximity of major port activities to capture emissions from the transfer of phosphates, coal, grains, sugar and others. A background sampler was stationed in an area used exclusively for long term storage of containers. All samplers were elevated between 2 to 5 meters above ground to minimize filter contamination by emissions from vehicles and other ground sources. The calibration of the samplers and the management of the filters was done in accordance with the sampling guide provided by the supplier of the sampling equipment. Following a review of USEPA approved models, the Industrial Source Complex (ISC3ST) was selected for the modeling task. A certain variability of the results are expected using the ISC. This is due to the fact that, by definition, the results of the ISC are an average of numerous repetitions of the same emission event. According to the USEPA, the local and temporal variations of individual values can be more than 50%. These deviations are important in the interpretation of the modeling results and the development of pollution mitigation strategies. 3. DATA QUALITY A dedicated technician from the LPEE collected filter samples every 8 hours, starting at 06:00 hours, August 28, 1999, and ending at 23:00 hours, September 15. Hourly meteorological data were obtained from the station CASA-ANFA located at the airport. Previous studies have shown that the meteorological data from that station are applicable to the region of the port of Casablanca. The meteorological data was partitioned into 8-hour intervals corresponding to the filter changes. Given the site topography, sampling episodes selected for the inverse modeling are those where the dominant air flow is from the northwest, north, and northeast. This was achieved by averaging the northwest and northeast vector (normal) components, and averaging the southwest and southeast vector (tangential) components. The data sets with the highest normal component and lowest tangential component were deemed reliable. In contrast, if the tangential components were elevated or if the wind is calm, then the data set was considered unreliable. 2

3 During the entire 431 hours of sampling, the northwest and northeast wind velocity components are dominant. Following our definition of the normal and tangential velocity, the normal wind velocity was found to be 270% greater than the tangential velocity. Thus, as a whole, the entire data set was deemed reliable for the inverse model. Further, as mentioned earlier, the data was divided into 44 8-hour intervals corresponding to the change out of the filters. Of these, 10 data sets (Table 1) were deemed reliable due to favorable wind velocity and direction. 4. INVERSE MODEL For each of the 11 data sets selected (10 8-hour sets, and the 431-hour data set), the particulate concentrations at the sampler locations were calculated at different emissions rates, as shown in Figures 2 and 3 for the 431-hour data set. At each iteration, the Correlation Coefficient (R) and the Pearson Square Correlation Coefficient (RSQ) were calculated for the ensemble of concentrations measured and simulated for the four sampling locations. The simulations with R greater than 0.9 and corresponding RSQ greater than 0.81 were judged to be reliable estimates of the emissions of the major sources. The 431-hour data and seven (7) 8-hour data produced R and RSQ values above the criteria and deemed reliable. Based on these results, the mean particulate emissions from the port were determined to be approximately 14 g/s or 252 metric tonnes/year based on 16-hour work, 6 days per week. The maximum emissions from the port for any 8-hour episode were estimated to be approximately 292 g/s or 8.4 metric tonnes/8-hours (Table 2). 5. PARTITION OF EMISSION SOURCES The chemical composition of the emissions of the phosphate products is relatively homogeneous compared to emissions from the other sources at the port of Casablanca. Notably, the content of elemental phosphor in the filters is used as a tracer to indicate the relative contribution of the phosphates to the overall particulate emissions from the port. To do this, a 25% section of each of the 44 filters was cut out and analyzed for phosphor content. The resulting data was reviewed for consistency, with a handful of sample results rejected due to laboratory analysis errors. The bulk of the port phosphate exports consist of single superphosphate, with elemental phosphor content of about 7%. Based on this information, the tracer method measurements for the 431-hour data, yielded phosphate emissions at 42% with a range from 5% to 72% for any 8-hour episode. In contrast, the inverse modeling showed that the relative emissions of the phosphates are about 39% for the 431-hour simulation. Three (3) 8-hour simulations produced phosphate contributions that are similar to the tracer method. Four (4) 8-hour simulations did not agree. This is possibly due to laboratory testing errors, or to naturally occurring phosphore content in some of the other minerals exported at the port, e.g., fluorine. 6. HEALTH ISSUES According to the World Bank guidelines, the maximum allowable ambient air particulate concentration is 100. The USEPA limitation is 50. Based on the study results, the ambient air particulate concentration in the vicinity of the port of Casablanca was measured 3

4 as high as 2,054. Further, the measured particulate concentrations exceeded the World Bank guidelines more than 95% of the time, and the USEPA guidelines 100% of the time. 7. SUMMARY AND CONCLUSION The atmospheric emissions from the port de Casablanca operations are obtained using an integrated methodology of field sampling and inverse mathematical modeling, and subject to rigorous data quality assurance and quality control. This innovative approach resulted in a quantifiable estimate of emissions sources from the port at 252 metric tonnes/year, with approximately 39% produced from the phosphate operations. The emissions are mostly fugitive emissions due to the technology used in the loading and unloading operations. In comparison, other international harbors (e.g., the Los Angeles Long Beach Harbor) control particulate emissions by relying on containers and, where necessary, completely enclosed transfer systems. The measured concentrations in the vicinity of the port of Casablanca exceeded the World Bank guidelines more than 95% of the time, and the USEPA guidelines 100% of the time. A risk assessment is needed to assess the impact of these particulate levels on the health of population in the vicinity of the port. The long-range transport of particulate emissions should be done to determine the impact of these emissions on the Casablanca metropolis. In future phases of this work, these results will be integrated with the other emissions inventory of the metropolitan region of Casablanca to develop a long-term monitoring and air quality forecasting program. RELATED MATERIALS 1. Code of Federal Regulations (Title 40, part 51): Protection of the Environment; Requirements for Preparation, Adoption, and Submittal of Implementation Plans. 2. Environmental Protection Agency, Guidelines for the Regional Evaluation of State and Local New Source Review Pro-gram. EPA Publication No. EPA 450/ U.S. Environmental Protection Agency, Re-search Triangle Park, NC. (NTIS No. PB ) 3. Code of Federal Regulations (Title 40, part 50): Protection of the Environment; National Primary and Secondary Ambient Air Quality Standards. 4. Environmental Protection Agency, Model Clearinghouse: Operational Plan (Revised). Staff Report. U.S. Environmental Protection Agency, Research Triangle Park, NC. (Docket No. A 88 04, II J 1) 5. Environmental Protection Agency, Protocol for Determining the Best Performing Model. EPA Publication No. EPA 454/R U.S. Environmental Protection Agency, Research Triangle Park, NC. 6. Fox, D.G., Uncertainty in Air Quality Modeling. Bulletin of the American Meteorological Society, 65(1): Schwartz, Joel, Douglas Ockery, and Lucas Neas. Is Daily Mortality Associated Specifically with Fine Particles?. Air and Waste Management Association. Volume 46, pp , October

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8 TABLE 1 INVERSE MODELISATION OF EMISSIONS AT PORT OF CASABLANCA Sampling Point 1 Sampling Point 2 Sampling Point 3 Sampling Point 4 File No. Duration (Hours) Measured Particles Simulation Particles Measured Particles Simulation Particles Measured Particles Simulation Particles Measured Particles Simulation Particles A ,060 1, A ,054 2, A A , , B (0.21) A A C ,622 1, D A ,039 1, ODEP TABLE 2 ESTIMATES OF EMISSIONS FROM VARIOUS SOURCES AT THE PORT OF CASABLANCA File No. A83113 A90122 A90314 Source Duration Phosphate g/s Charbon g/s Sucre g/s Divers g/s Minerais g/s Cereales g/s TOTAL g/s Daily Tonnes/8-Hr Annual Tonnes/Yr 252 A90722 A91223 C91315 D91323 RSQ ODEP 99 R 8