The consumption of fuel is associated with a number of environmental issues. One of the major environmental concerns is the increasing greenhouse gas (GHG) emissions and air pollution. GHG emissions and air pollution are mainly from the human activities such as transportation, non-renewable electricity production, oil and gas production, and heating and cooling of buildings. In this thesis, a comprehensive review was conducted to assess the impact of elements in urban form on on-road vehicles GHG emissions. A small-medium North American city case study was given to track the progress in reducing real-world emissions over time and to estimate the future air quality impacts based on the trends of fleet mixes. It helps gain understanding of detailed source apportionment information to quantify the contributions to total emission made by different vehicle body types, different fuels, and manufacturer models in recent decades and how the fuel economy of the vehicle fleet has changed over the years. Following that, an assessment was conducted to analyze the impact of COVID-19 pandemic on GHG emissions from urban transportation and air quality in Canadian cities. The reduced traffic experienced throughout several lockdowns offers a glimpse of what air quality in cities would look like if the country switched to low-carbon transportation modes. Finally, the reductions in NO2 emissions from thermal power plants in Canada were assessed to evaluate the government commitment of switching from fossil fuels to clean energy. The satellite observation was developed as a supplementary information management tool to verify the effect of technologies and policies on emissions changes from threshold perspective on a smaller spatial scale. Overall, this thesis provides some new insights on assessing air pollution and carbon emission levels from transportation and electricity sectors.