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## A4.2.2 Parking Facilities 

Parking emissions are a compound function of how many vehicles are entering and exiting airport parking facilities (i.e., garages and surface lots) , the distance they travel to access and egress the parking area, and any idling time incurred as the vehicles queue either in waiting for a space or to enter or exit. The travel-based component of the parking emissions can be estimated by applying Equation A4-1 ( Total Pollutant Emissions from Travelling Motor Vehicles ). The idling-based component of the parking emissions may be quantified by applying Equation A4-2 ( Total Pollutant Emissions from Motor Vehicles Idling ). Emissions should be estimated for each on-site and/or off-site parking facility associated with the airport. A typical idle time is 1.5 minutes and a typical travel distance is equivalent to twice the diagonal of the parking area. 

Where: 

E$_{Idling }$ = total idling motor vehicle emissions of pollutant (i.e., CO, SO$_{2}$, PM$_{10}$, PM$_{2.5}$, NO$_{x}$, or VOC), for a given time period, expressed in pounds. 

CF = factor to convert grams to pounds (i.e., 0.0022046) 

<img src='content_image/588788.jpg'>

AADT$_{j }$= average annual daily traffic counts by vehicle type j for the parking facility. 

IT$_{j }$= idling time, expressed in minutes per vehicle type j. 

ER$_{j }$ = emissions rate of pollutant from idling considering speed of vehicle type j, expressed in grams per minute. 

j = vehicle type (e.g., Honda Civic). 

Emissions from the terminal curbside areas are based on the number of vehicles traveling to these areas, the distance of the curbside area and the amount of idling time incurred as these vehicles pickup and drop-off passengers. The approaches discussed previously for roadways and parking facilities may be applied to estimate motor vehicle emissions from terminal curbside areas. Therefore, the travel- and idling-based components of these emissions may be quantified by applying Equation A4-1 ( Total Pollutant Emissions from Traveling Motor Vehicles ) and Equation A4-2 ( Total Pollutant Emissions from Motor Vehicles Idling ), respectively. A typical idle time ranges from 1.5 to 6.0 minutes depending on vehicle type and a typical travel distance is equivalent to length of the terminal curbside holding area. 

Total emissions from roadway, parking and curbside motor vehicle activities may be obtained by summing the travel emissions based on VMT and the idling emissions based on hours operation, as shown by Equation A4-3 ( Total Pollutant Emissions from Motor Vehicles ). 

