Explanation

Incomplete combustion during open field crop stubble and biomass burning produces a complex mixture of gaseous pollutants and particulate matter:

– 1. Carbon monoxide (CO): Emitted abundantly as a direct by-product of incomplete biomass combustion.
– 2. Methane (CH4): Released from oxygen-starved smoldering phases of agricultural fires.
– 4. Sulphur dioxide (SO2): Released through the oxidation of organic sulfur compounds naturally present in crop plants and soil residue.
– 3. Ozone (O3): While ground-level tropospheric ozone is a secondary photochemical oxidant rather than a primary furnace effluent, the intense heat of biomass fires rapidly drives the photochemical interaction of co-emitted nitrogen oxides (NOx) and volatile organic compounds (VOCs) to generate ozone right above burning plumes.

Therefore, all four are released into the atmosphere — Option D.