# Benefits of Advanced Air Mobility for Society and Environment: A Case Study of Ohio
## 4 Benefit Factors
### BF-9: Savings in Social Cost of Greenhouse Gases  
Scientists and the general public have been concerned about the possible repercussions of climate change for many years now. Conventional fossil Fuel-powered Ground Vehicles (CFGV) are one of the most significant sources of carbon emissions as they burn tons of gallons of fuel every year, resulting in global warming, increasing pollution levels and a variety of consequent health issues. Switching to eVTOLs from CFVs can assist in alleviating the problem of excessive carbon emissions. It offers a new paradigm shift in green transportation, striving for a carbon-neutral and sustainable environment. _Social Cost of Carbon (SCC)_, _Social Cost of Methane (SCM)_, and _Social Cost of Nitros Oxide (SCN)_ are used for monetary assessment of the social damage caused by emitting one metric ton of carbon dioxide (\(CO_{2}\)), methane (\(CH_{4}\)) and nitrous oxide (\(N_{2}O\)), respectively. These values reveal how much it is worth to us to avert future damage to our environment by avoiding the emission of these gases. After inflation adjustments, the interim _SCC_ was valued at $51 per metric ton \(CO_{2}\) by the [PERSON] administration using a 3% average discount rate (\(r\)) in 2020 [80]. The 2020 global \(SCM\) was estimated to be $1200 per metric ton \(CH_{4}\) using a 3% discount rate by the inter-agency working group on _Social Cost of Greenhouse Gases (SCGHG)_, United States Government; and, for \(SCN\), the value was estimated to be $1500 per metric ton \(N_{2}O\)[81]. Using 3% discount rate, we forecasted the future value of SCC (\(F_{SCC}\)) for year \(i\):  
\[F_{SCC_{(i)}}=SCC\times(1+r)^{t}\qquad i\in\{2022,...,2032(year)\};t\in\{2,3,...,12\}. \tag{52}\]  
Similarly, we obtained \(F_{SCM}\) for \(CH_{4}\) and \(F_{SCN}\) for \(N_{2}O\) using Equations (53) and (54), respectively:  
\[F_{SCM_{(i)}}=SCM\times(1+r)^{t}\qquad i\in\{2022,...,2032(year)\};t\in\{2,3,...,12\} \tag{53}\]  
\[F_{SCN_{(i)}}=SCN\times(1+r)^{t}\qquad i\in\{2022,...,2032(year)\};t\in\{2,3,...,12\} \tag{54}\]  
The average social cost of \(F_{SCM}\) and \(F_{SCN}\) is \(F_{SCMN}\):  
\[FSC_{MN_{(i)}}=\frac{F_{SCM_{(i)}}+F_{SCN_{(i)}}}{2}\qquad i\in\{2022,...,2032( year)\}. \tag{55}\]  
In 2018, the weighted average combined fuel mileage (\(MPG\)) of vehicles and light trucks was 22.5 m per gallon [82]. Then, using _VMT_' (see Section 4.2) and \(MPG\), we measured \(N_{g(i)}\), which refers to the estimated number of gallons of fuel burned in year \(i\) in SMCO:  
\[N_{g_{(i)}}=\frac{VMT_{i}^{\prime}}{MPG}\qquad i\in\{2022,...,2032(year)\}. \tag{56}\]  
Carbon dioxide emissions as a proportion of total GHG emissions--including carbon dioxide, methane and nitrous oxide, emissions--for passenger vehicles (\(F_{eq}\)) was 0.993 in 2018. The amount of \(CO_{2}\) produced from burning each gallon of gasoline (\(g_{C}\)) is 8.89 \(\times\) 10\({}^{-3}\) metric tons [82]; and the amount of \(CH_{4}\) and \(N_{2}O\) produced for burning each gallon of gasoline (\(g_{MN}\)):  
\[g_{MN}=g_{C}\times(\frac{1}{F_{eq}}-1). \tag{57}\]  
Thus, the amount of \(CO_{2}\) (in metric ton) emitted in year \(i\) in SMCO (\(A_{C}\)) is:  
\[A_{C_{(i)}}=g_{C}\times N_{g_{(i)}}\qquad i\in\{2022,...,2032(year)\}. \tag{58}\]  
Similarly, the amount of combined \(CH_{4}\) and \(N_{2}O\) (in metric ton) emitted in year \(i\) in SMCO (\(A_{MN}\)) is:  
\[A_{MN_{(i)}}=g_{MN}\times N_{g_{(i)}}\qquad i\in\{2022,...,2032(year)\}. \tag{59}\]  
The use of eVTOLs instead of CFGV for transportation will help to reduce the amount of emissions generated from the existing ground transportation system because eVTOLs have lower life cycle emissions than their ground counterparts. There are five stages in the life cycle of an eVTOL: (i) the manufacturing of components of the vehicle, (ii) the manufacturing of components of batteries, (iii) transportation of the vehicle from the assembly plant to the user, (iv) vehicle use, and (v) end of life [83].