The Comprehensive Automobile Research System (CARS) – a Python-based automobile emissions inventory model
<p>The Comprehensive Automobile Research System (CARS) is an open-source Python-based automobile emissions inventory model designed to efficiently estimate high-quality emissions from motor vehicle emission sources. It can estimate air pollutant, greenhouse gas, and air toxin criteria at any s...
| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2022-06-01
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| Series: | Geoscientific Model Development |
| Online Access: | https://gmd.copernicus.org/articles/15/4757/2022/gmd-15-4757-2022.pdf |
| Summary: | <p>The Comprehensive Automobile Research System (CARS) is an open-source
Python-based automobile emissions inventory model designed to efficiently
estimate high-quality emissions from motor vehicle emission sources. It can
estimate air pollutant, greenhouse gas, and air toxin criteria at
any spatial resolution based on the spatiotemporal resolutions of input
datasets. The CARS is designed to utilize local vehicle activity data, such
as vehicle travel distance, road-link-level network geographic information
system (GIS) information, and vehicle-specific average speed by road type,
to generate an automobile emissions inventory for policymakers,
stakeholders, and the air quality modeling community. The CARS model adopted
the European Environment Agency's on-road automobile emissions
calculation methodologies to estimate the hot exhaust, cold start, and
evaporative emissions from on-road automobile sources. It can optionally
utilize average speed distribution (ASD) of all road types to reflect more
realistic vehicle speed variations. In addition, through utilizing high-resolution
road GIS data, the CARS can estimate the road-link-level emissions to
improve the inventory's spatial resolution. When we compared the official
2015 national mobile emissions from Korea's Clean Air Policy Support System
(CAPSS) against the ones estimated by the CARS, there is a significant
increase in volatile organic compounds (VOCs) (33 %) and carbon monoxide
(CO) (52 %) measured, with a slight increase in fine particulate matter
(PM<span class="inline-formula"><sub>2.5</sub></span>) (15 %) emissions. Nitrogen oxide (NO<span class="inline-formula"><sub><i>x</i></sub></span>) and sulfur oxide
(SO<span class="inline-formula"><sub><i>x</i></sub></span>) measurements are reduced by 24 % and 17 %, respectively, in the CARS
estimates. The main differences are driven by different vehicle activities
and the incorporation of road-specific ASD, which plays a critical role in
hot exhaust emission estimates but was not implemented in Korea's CAPSS
mobile emissions inventory. While 52 % of vehicles use gasoline fuel and
35 % use diesel, gasoline vehicles only contribute 7.7 % of total NO<span class="inline-formula"><sub><i>x</i></sub></span>
emissions, whereas diesel vehicles contribute 85.3 %. However, for VOC emissions,
gasoline vehicles contribute 52.1 %, whereas diesel vehicles are limited to
23 %. Diesel buses comprise only 0.3 % of vehicles and have the
largest contribution to NO<span class="inline-formula"><sub><i>x</i></sub></span> emissions (8.51 % of NO<span class="inline-formula"><sub><i>x</i></sub></span> total) per
vehicle due to having longest daily vehicle kilometer travel (VKT). For VOC
emissions, compressed natural gas (CNG) buses are the largest contributor at
19.5 % of total VOC emissions. For primary PM<span class="inline-formula"><sub>2.5</sub></span>, more than 98.5 %
is from diesel vehicles. The CARS model's in-depth analysis feature can
assist government policymakers and stakeholders in developing the best
emission abatement strategies.</p> |
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| ISSN: | 1991-959X 1991-9603 |