However, humans have been actively affecting the CO2 natural balance through activities that increase the accumulation of these gases in the atmosphere, a factor contributing to increased accumulation of the greenhouse gases in the atmosphere. The typical combustion activities include burning of natural gases, oil coal and in transportation, where vehicles are the main contributors of pollution. In the US today, combustion of gasoline in transportation services accounts for 32% of the total emissions in the country and 27% of all greenhouse emissions. it is .the second largest contributor of greenhouse gases in the atmosphere (Brugge, 3). Consequently, vehicles using gasoline are the second most significant source of greenhouse gases in the U.S, raising concerns on the use of carbon-based fuels. This practical was aimed at measuring the levels of carbon dioxide emitted by vehicles at two busy locations within the school. The aim was .to understand the effect of high vehicle densities and the differences in concentration of CO2 gas at two different locations.
Vehicles play a significant role in increasing the levels of carbon dioxide in the atmosphere. As has been stated above, combustion is one of the major human activities has been blamed for increased cases of greenhouse gases. A primary agent of combustion that steadily increases the accumulation of these gases is the use of carbon-based fuels. As such, the testing of carbon dioxide levels in the parking area and at the school exit seeks to indicate the role played by vehicles in increasing the levels of emissions in the atmosphere.
Utmost care was observed when handling the sensitive instrument to avoid damage.  .Two or more people .had .to carry the device while holding the S.S probe .in position. The probe was also prevented from touching the ground where it could collect data and get damage.
An important observation during the experiment was that when placing the digital CO2 sensor in the required