What is released into the atmosphere when humans burn fossil fuels?

Answer 1

The most common gaseous pollutants in the atmosphere are carbon dioxide, carbon monoxide, hydrocarbons, nitrogen oxides, sulfur oxides and ozone (and methane not caused by burning fuel but a gas created by decomposition of garbage and green waste as well as livestock farming.

The above pollutants are considered greenhouse gases because they trap heat inside our atmosphere. A number of sources produce these chemical compounds but the major man-made source is the burning of fossil fuel.

Particulate matter is also caused by burning fossil fuels. Particulate matter is not a gas but extremely fine particles. Particulate matter is believed to be the number one cause of pollution related lung disease and cancer. Particulate matter is commonly released by diesel engines.

Answer 2

Each ton of fossil fuel burned produces 2-3 tons of carbon dioxide depending on which fuel is being used, plus smaller quantities of water vapour and other chemicals.

There's no way of avoiding this because it's the formation of carbon-oxygen chemical bonds in the carbon dioxide that produces the energy used in heat engines (petrol and diesel engines, gas turbines) or in boiling the water for steam turbines.