a) According to the US DOT/FHWA, vehicle miles traveled (VMT) in December 2021 was 26.9 billion more miles than in December 2020. If the average fuel economy was 25 MPG, what was the increase in CO2 emissions (in kg) from this increase in VMT? EPA gives an emission factor of 8.8 kg CO2 per gallon of motor gasoline.

b) Due to the pandemic, VMT for the period February 2020 - January 2021 dropped from 3.28 to 2.84 trillion miles. What was the decrease in CO2 emissions (in kg) associated with the decrease in VMT?