Electricity generation, primarily from fossil fuel combustion, is the largest source of CO2 emissions worldwide.

Agriculture, particularly livestock production and rice cultivation, is the dominant source of methane emissions.

Agriculture, specifically the use of nitrogen-based fertilizers and manure management, is the primary source of nitrous oxide emissions.

Refrigeration and air conditioning systems are major contributors to HFC emissions.

Industrial processes, such as aluminum production and semiconductor manufacturing, are the main sources of PFC emissions.

Industrial processes, particularly electrical equipment manufacturing and magnesium production, are the primary sources of SF6 emissions.

Residential heating, particularly the use of solid fuels like coal and wood, is the main source of black carbon emissions.

Residential heating, particularly the use of solid fuels like coal and wood, is the main source of organic carbon emissions.

Transportation, primarily from the combustion of fossil fuels in vehicles, is the main source of carbon monoxide emissions.

Transportation, primarily from the combustion of fossil fuels in vehicles, is the main source of nitrogen oxides emissions.

Transportation, primarily from the evaporation of gasoline and diesel fuel, is the main source of volatile organic compounds emissions.

Industrial processes, particularly those involving combustion and the handling of solid materials, are the main sources of particulate matter emissions.

Electricity generation, primarily from the combustion of fossil fuels, is the main source of sulfur dioxide emissions.

Agriculture, particularly livestock production and the application of nitrogen-based fertilizers, is the main source of ammonia emissions.

Industrial processes, particularly those involving the refining of petroleum and the production of pulp and paper, are the main sources of hydrogen sulfide emissions.