Consider the following: 1. Carbon monoxide 2. Methane 3. Ozone 4. Sulphur dioxide Which of the above are released into atmosphere due to the burning of crop/biomass residue?

1. The burning of crop/biomass residue is a process of incomplete combustion which releases various pollutants into the atmosphere. 2. Statement 1: Carbon monoxide (CO) is a common product of incomplete combustion of organic matter and is definitely released. 3. Statement 2: Methane (CH4), a potent greenhouse gas, is also released during the incomplete combustion of biomass. 4. Statement 3: Ground-level Ozone (O3) is generally a secondary pollutant formed from precursors like Nitrogen Oxides (NOx) and Volatile Organic Compounds (VOCs) which are released during biomass burning. While not directly emitted in large quantities like CO or CH4, its formation is a direct consequence, and emissions lists often include it or its precursors. 5. Statement 4: Sulphur dioxide (SO2) is released if the biomass being burnt contains sulphur. While often lower than in fossil fuels, sulphur is present in biomass, leading to SO2 release upon burning. 6. Therefore, all four gases listed are either directly released or their formation is significantly enhanced due to the burning of crop/biomass residue.