M. El-Fadel^, S. Shazbak®...Environmental impacts of parking facilities in urban areas M....

Environmental impacts of parking facilities in

urban areas

M. El-Fadel , S. Shazbak®^ Department of Civil & Environmental Engineering, American[ zv jzYy q/ gzyK &50 TTzW v ^ A^M/ 7b 7V7 70022,EMail: [email protected]^ Department of Civil & Environmental Engineering, AmericanUniversity of Beirut, P.O. Box: 110236/2611, Beirut, LebanonEMail: [email protected]

Abstract

Parking problems in major urban centers are typically an accumulation of theeffects of several factors, including short sighted urban planning regulations,pricing distortions, ineffective enforcement and vague transport and parkingpolicies. This paper presents an environmental impact assessment of a proposedparking structure (typical of many other proposed ones) in the Beirut area whereparking deficiencies have increased significantly in recent years due to post-wardevelopment and reconstruction efforts. The focus of this assessment is on theevaluation of potential noise and air quality impacts of the proposed parkingfacility and the definition of corresponding mitigation measures to alleviateadverse impacts. The assessment was conducted using both field measurementsand computer simulation models.

Introduction

Shortages in parking availability in urban areas are a common feature for manydeveloping areas especially those which have evolved without prior planning andexplicit building regulations. Such is the case of the City of Beirut where randomconstruction activities occurred (during nearly two decades of civil unrest) withdisregard to zoning regulations which require parking provisions based on landuses. By the early 1990s, old decrees were amended and new regulations were set

Transactions on the Built Environment vol 41, © 1999 WIT Press, www.witpress.com, ISSN 1743-3509

248 Urban Transport and the Environment for the 21st Century

requiring developers to provide a parking space for each: (1) 125 nf apartment;(2) 4 hotel rooms; (3) 30 nf restaurant; and (4) 40 nf office. While theseregulations appear appropriate to reduce parking problems, their enforcement hasnot been properly observed and as a result, the parking problem persists and infact, continues to increase. Construction of parking facilities is proposed as apotential solution for this problem. This paper presents an assessment of a typicalfacility. In the present context, the assessment is limited to air and noise impacts.

Site Description

The proposed facility is the site of an existing small municipal garden and islocated in a mixed commercial and residential area. The capacity of the facility isexpected to increase the peak hourly volume by less than one hundred vehiclesand is designed as a several story underground structure in order to preserve thegarden despite the increase in capital and operation/maintenance cost. A sitelayout with current and future traffic counts as well as sensitive receptor locationsare depicted in Figure 1.

Figure 1. General layout of proposed parking facility


Urban Transport and the Environment for the 21st Century 249

Impact Assessment

The impact analysis focused on comparing the expected site evolution with andwithout the implementation of the project components. The impacts areaddressed in accordance to the phases of the project namely, construction andoperation. The magnitude of these impacts varies with time and site management.Generally, the environmental issues that are associated with an undergroundparking facility are presented in Table 1.

Table 1. Classification of environmental impacts

Category

Short term

Long term

Phase

Construction

Operation

Duration(W<2

>2

Potentially Impacted Parameter

a TrafficQ Air QualityG NoiseQ Landscape and Visual IntrusionQ Waste GenerationQ Water QualityQ Health and SafetyG ArcheologyU Socio-Economicsa TrafficQ Air QualityQ NoiseQ Landscape and Visual IntrusionQ Health and SafetyQ Socio-Economics

While the impacts of some parameters can be assessed quantitatively usinganalytical and mathematical means (air, noise), the impacts of other parameterscan be described by relying on a qualitative approach. There are for instance,well established methods for the measurement of traffic counts, air pollution,noise levels, and economic benefits in the context of a parking facility. For otherparameters however, a qualitative and comparative approach can be adopted.Only air and noise impacts are addressed below.

Air Impacts and Mitigation

In order to assess the extent of potential air quality impacts at a parking facility,applicable air quality standards and existing conditions were first defined, andmathematical simulations were then conducted to estimate current and futureatmospheric concentrations of selected pollutants typically emitted from vehicles.The estimations were performed for several scenarios including existing andfuture conditions with and without a parking facility.



Applicable Air Quality StandardsTable 2 presents air quality standards for selected constituents as promulgated bythe US Environmental Protection Agency (EPA) and used in this work for impactassessment.

Table 2. Ambient air quality standards

Pollutant

Nitrogen Dioxide (NC )Carbon Monoxide (CO)

Standard//g/rn #?W100(0.053)10,000(9)

AveragingPeriod1 year8 hours

Existing Air Quality ConditionsExisting data on air quality in Beirut are practically non-existent. Air sampleswere collected in the vicinity of the proposed parking facility. The samples wereanalyzed for selected constituents. The average measured concentration in air ofNO? and TSP was 283 and 183 jig/nt*, respectively both exceeding ambient airquality standards.

Air Quality SimulationsConstruction Phase Air emissions during the construction phase are a functionof the excavation scheme and machinery used on-site. It consists primarily ofparticulate dust matter released as a result of earth removal activities and to alesser extent, emissions from the on-site usage of heavy construction equipment.For this phase, it is expected that negative impacts on air quality will occur in andaround the immediate vicinity of a site under construction. While the extent ofthis impact cannot be reasonably quantified in a scientific manner due to therandom nature of construction activities, it is typically temporary and confined tothe site vicinity particularly if proper management measures are adopted asdescribed below in the impact mitigation.

Operation Phase During the operation phase, which is the most significantphase with respect to air quality, air emissions will be a function of the expectedtraffic conditions (volume and speed) at a particular location as well as the fleetcharacteristics. Air quality dispersion modeling is used to estimate contaminantexposure levels at a certain location. Potential sources (congested roads aroundthe parking facility) coupled with least favorable meteorological conditions(AUB ) are used to simulate the worst-case exposure scenario. The mathematicalmodel CALINE4 was applied to predict pollutant concentrations in the air atselected receptors (Figure 1). The model uses the sub-model EMFAC, to estimatecomposite on-road emission factors (ARB*). Table 3 presents a summary of thesimulations conducted to predict current and future concentrations in the air ofconstituents emitted from transport activities around the parking facility.



Table 3. Average simulated air pollutant concentrations

Pollutant

CO (ppm)NO% (ppm)

Present79&S7.120.212

Without parking20707.820.214

With parking20707.820.214

Values in Table 3 represent the average constituent concentration from severalreceptors located at ground level. Note that these values are the contribution oftraffic emissions to the concentration of a particular pollutant in the air. They donot account for other industrial sources in the area. For instance, simulatedparticuiate matter concentrations are far less than field measurements indicatingthat the transport sector is not the only source for particuiate in the air. This is notsurprising especially that gasoline is the main fuel used in Lebanon and dieselusage is restricted to trucks and busses. The elevated particuiate concentrationscan be attributed to construction activities associated with the large effort of postwar rehabilitation. In contrast, the simulated concentrations of NC>2 are within thesame order of magnitude as those measured in the field indicating that thetransport sector is a major source of NCX

Evaluation of Potential Air Quality ImpactsThe assessment of the impact significance of air emissions is conducted bycomparing the estimated contaminant exposure levels with existing air qualityconditions and ambient air quality standards. The simulated results are depictedin Figure 2 with the corresponding air quality standards used for comparisonpurposes. It is evident that the proposed design does not present any additionalnegative air quality impacts when compared with the base condition withoutproject implementation in the year 2010. However, when compared with 1998levels, air quality has deteriorated which is not surprising given that the roadcapacity has increased and the car fleet characteristics are assumed to remainunchanged in terms of maintenance and inspection. While this indicates that nonegative impacts will result from the project as compared to base conditions, itdoes not preclude the need for mitigation measures to address base conditionsparticularly with respect to NC>2 emissions.

Note that within a parking facility, the concept of a box model can be appliedto estimate indoor exposure levels and air ventilation requirements. In this case,pollutant concentration estimates should be compared to allowable contaminantexposure levels in an occupational setting to assess the extent of impacts from carexhaust emissions on workers and customers inside the parking facility.



9

I 8,a 7.87

?>6

19

7.82

12 ,, ;/5" \#<(\"% ^ \^\

98 2010Withoutparking

7.82

#

2010With

parking

0 3 -,

H 0.2 -D-5 o.i -

0.212 0.214 0.214

El B §0 -» * *"• 1 — — ! •- ' f

1998 2010 2010Without Withparking parking

Figure 2. Air emission simulations with and without the parking facility

Mitigation of Potential Air Quality ImpactsDuring the construction phase, it is essential to adopt strategies to prevent orminimize dust emissions. The main control measures towards this purposeinclude: (1) proper site enclosure; (2) on-site mixing and unloading operations;(3) maintaining minimal traffic speed on-site; (4) ensuring adequate maintenanceand repair of construction machinery; and (5) proper water spraying whennecessary. At the conclusion of construction activities, while the proposed projectwill not result in negative air quality impacts at the operational level, besidesmaintenance of the parking facility ventilation system, long term mitigation plansare necessary to address air quality particularly that transport emissions constitutethe major source of air pollutants in urban areas (Staudte et al?). Long termmeasures include (1) adoption of emission reduction technologies; (2) regulationsfor vehicle inspection and maintenance system; and (3) air quality monitoring.

Noise Impacts and Mitigation

In order to assess the extent of potential noise impacts of the proposed facility,applicable noise level standards and existing conditions were first defined, andmathematical simulations were then conducted to estimate current and futurenoise levels. The estimations were performed for several scenarios including withand without a parking facility. An assessment of the impact significance of noiselevels is then conducted by comparing the estimated noise exposure levels withexisting noise level conditions and accepted noise abatement criteria.

Applicable Noise Level StandardsTable 4 presents noise abatement criteria as adopted by the US Department ofTransportation (DOT) and used in this work for impact assessment.



Table 4. Summary of noise abatement criteria (USDOT*)

Land usecategoryA

B

CDE

Leyd&4

57 (exterior)

67 (exterior)

72 (exterior)

—52 (interior)

Description of land use category

Land where serenity and quiet are of extraordinaryimportance and serve an important public need andwhere the preservation of those qualities is essential ifthe area is to continue to serve its intended purpose.Residences, motels, hotels, libraries, hospitals, publicmeeting rooms, schools, churches, recreational areas,picnic areas, playgrounds, parks.Developed lands, properties not included in A and BUndeveloped landResidences, motels, hotels, libraries, hospitals, publicmeeting rooms, schools, churches, and auditoriums

" equivalent noise level

Existing Noise LevelsWhile existing data on noise levels in the Beirut is relatively limited, recentsurveys indicate that current average noise levels exceed 75 dBA in manylocations (Chaban and Ayoub*). Noise level measurements were conducted in theimmediate vicinity of the proposed parking facility and showed an average noiselevel around 74 dBA.

Noise Level SimulationsConstruction Phase Typical construction activities associated with a parkingfacility include ground cleaning, soil excavation, foundation setting, structureerection and finishing. During these activities, various machinery and heavyequipment are used. The inverse square wave divergence concept for a pointsource was adopted to estimate noise levels at 30 m., which was assumed as thedistance from the point source to the center of gravity of nearby receptors. Table5 provides a summary of estimated noise levels for various construction phases.Note that these values are highly dependent on the actual equipment in operationat the time the estimation is made. Noise level values presented in Table 5 areaverage values of all equipment classified under a certain construction activity.

Table 5. Estimated average noise levels during the construction phase

f/KMg

Ground cleaning

Noise Level (dBA)(15 meters)

83Excavation | 85FoundationErectionFinishing

868283

Noise Level (dBA)(30 meters)

7779807677



Operation Phase Noise level attenuation modeling was conducted to estimatenoise exposure levels around the proposed parking facility. For this purpose, theCommunity Noise Model (CNM) was applied to predict noise emissions forvarious traffic conditions and the sound levels experienced at nearby locations.The model relies on the Federal Highway Administration noise prediction model(which predicts noise level at a perpendicular distance away from a source withconstant speed along a highway) all while accounting for potential traffic signals(CNM*). Table 4-13 provides a summary of simulated results for existingconditions (1998) and the year 2010 with and without the proposed parkingfacility. Note that the results are averages obtained from several receptor pointslocated at ground level.

Evaluation of Potential Noise ImpactsConstruction Phase It is evident that the construction activities will have agreater negative impact on receptors within a 30 meter radius. Noise levels wereall in the vicinity of 80+ dBA at 15 m. and in the high 70s dBA at 30 m. Thesevalues exceed permissible noise level standards and abatement criteria. Notehowever that noise from construction activities is confined to certain number ofhours, not all the equipment are functional at the same time, and the main area ofactivity may move around the site. Furthermore, construction noise is temporaryand will diminish when the project is commissioned.

Operation Phase At the operational level which represent the long term phaseof the project, the estimated noise levels are depicted in Figure 3 with thecorresponding noise level standards used for comparison purposes. During thisphase, an insignificant increase in noise levels occurs with the proposed projectin the year 2010. While this indicates that no negative impacts will result fromthe project as compared to base conditions, it does not preclude the need formitigation measures to address the starting base condition. Note that within aparking facility, noise levels can be compared to allowable exposure levels in anoccupational setting to assess the extent of impacts of vehicle noise emissions onworkers and customers inside the parking facility or an underpass.

73

72

71

72.4

- " *' "', ^

^ %

72,8

§

778

1998 20 10 Without 2010 Withparking parking

Figure 3. Noise level simulations with and without the parking facility



Mitigation of Potential Noise ImpactsThe major mitigation measures required are during the construction phase. Theextent to which construction noise impacts may be mitigated is more limitedthan on fixed operational sites because of the mobile sources. Moreover, the factthat much of the work is performed in the open, overly restrictive workingmeasures might unreasonably prolong the construction phase. Typicalmitigation measures that may be enforced to minimize noise levels include (1)choices of inherently quiet equipment; (2) proper site logistics and planning; (3)proper maintenance of equipment; (4) limiting site working hours if possible;(5) informing the local when noisy activities are planned; (6) placing mufflingdevices that will reduce vibration; (7) scheduling noisy activities during themorning hours; (8) enforcing noise monitoring; and (9) keeping equipmentspeed as low as possible.

Simulation results showed that during the operation phase the net change innoise levels between the do nothing scenario and the proposed parking facilitydoes not warrant any mitigation measures. However, the existing noise levelsexceed acceptable standards and thus may warrant a mitigation plan. In thisregard, many abatement measures are not feasible in an urban context becauseof the geometry limitations and nearby land uses. Not enough land is availablefor the construction of noise barriers, acquisition of buffer zones or planting ofwide and dense vegetation cover to dampen noise levels. Unless advanced noisereduction technology is incorporated into the vehicle fleet, the only mitigationplan at hand is traffic management. One traffic management plan is truckrouting so that they take alternative routes at certain times of the day. Anotherwould be imposing speed limits, however, a 30 kph reduction is necessary forany decrease in noise level to be noticed. A third option would be encouragingHigh Occupancy Vehicles (HOV) over one-driver-vehicle. Future land useplanning can also help by imposing proper insulation on newly erectedbuildings.

Summary

An environmental impact assessment for a parking facility was conducted witha focus on the evaluation of potential noise and air quality impacts of the facilityand the definition of corresponding mitigation measures to alleviate adverseimpacts. The assessment showed that the greatest potential impacts will occurduring the construction phase with respect to dust and noise emissions. Duringthe operation phase, the impacts were minimal. Table 6 summarizes mitigationmeasures that can be considered in the two phases of the project.



Table 6. Summary of potential mitigation measures

Impact 1 Mil

Air quality Qaaaaaaaaaaa

Noise level Qaaaa

a

Air quality Qaaa

Noise level Gaa

igation Measure

Construction PhaseSite and stock pile enclosureSpraying of stockpiles with chemical bonding agentsOn-site mixing in enclosed or shielded areasProper unloading operationsWater damping of stockpiles when necessary (dry conditions)Sealing of completed earthworksRe-vegetation as soon as possibleMedium and heavily used haul routes permanently surfacedDamping unsurfaced haul routesKeep hauling routes free of dust and regularly cleanedMinimal traffic speed on-site with proper enforcementMaintenance and repair of construction machineryConstruction of site enclosureControl of timing of noise emissionsProper road maintenanceEnforcement of speed limitsEmploy low noise machinery, or machinery with noiseshielding and/or sound absorption materials (e.g. on-sitepower generator enclosure)Proper maintenance of equipment and machinery

Operation PhaseMaintenance of ventilation systemAdoption of emission reduction technologiesRegulations for vehicle inspection and maintenance systemAir quality monitoringSound insulation and pavement maintenanceLimiting vehicle speedRegulations for vehicle inspection and maintenance system

Acknowledgements

The authors wish to express their gratitude to TEAM International forproviding the project layout and data on traffic counts. Special thanks areextended to Mr. H. Sbayti and Mr. M. Bou Najm, Department of Civil andEnvironmental Engineering, American University of Beirut, for assisting in theair and noise simulations.



References

1. ARE (Air Resources Board), Methodology for Estimating Emissions fromon-Road Motor Vehicles (6 vols.), Technical Support Division, MobileSource Emission Inventory Branch, California EPA, 1996.

2. AUB (American University of Beirut), Weather Data Summary,Department of Mechanical Engineering, Beirut, Lebanon, 1996.

3. CNM (Community Noise Model), User's Manual, Department of CivilEngineering, Noise Laboratory, University of Central Florida, 1998.

4. Shaaban F. and Ayoub G. Database of Air and Noise Pollution. NationalCouncil for Scientific Research, Beirut, Lebanon, 1996.

5. Staudte, M., Rau, M. & El-Fadel, M., Urban Air Quality MonitoringProgram for the Greater Beirut Area, Transtec-Fitchner Consortium,Ministry of Environment, Beirut, Lebanon, 1997.

6. USDOT (Department of Transportation), Highway Traffic Noise Analysisand Abatement Policy and Guidance, Federal Highway Administration,Office of Environment and Planning, Noise and Air Quality Branch,Washington DC, 1995.


M. El-Fadel^, S. Shazbak®...Environmental impacts of parking facilities in urban areas M....

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