Method for the manufacture of a homogeneous, solid, particulate, urea-based composition comprising urea and an additive, in a urea production plant comprising at least an evaporator section, a particulation section, and an effluent gas treatment section and optionally a scrubber solution storage section and/or a mixing section, wherein the method comprises at least the steps of: (i) in the evaporator section, concentrating a urea melt to 95 to 99 weight% of urea; (ii) in the particulation section, particulating a urea or urea-based melt into an homogeneous, solid, particulate urea-based composition, thereby producing an effluent gas stream comprising urea-based dust particles and ammonia gas; (iii) in the effluent gas treatment section, treating the effluent gas stream from the particulation section comprising urea-based dust particles and ammonia gas with an aqueous solution to produce a scrubber solution; and optionally comprises one or more of the steps of: (iv) in the mixing section, if present, mixing the urea melt of 95 to 99 weight% of step (i) with other fertilizer components to produce a urea-based melt; and (v) in the scrubber solution storage section, if present, storing the scrubber solution from the effluent gas treatment section; wherein the additive is introduced into the urea or urea-based composition as an aqueous suspension, an aqueous dispersion, or an aqueous liquid, by adding the additive to one or more of: (a) said effluent gas treatment section; and/or (b) said scrubber solution storage section containing the scrubber solution, if present. (i) in the evaporator section, concentrating a urea melt to 95 to 99 weight% of urea; (ii) in the particulation section, particulating a urea or urea-based melt into an homogeneous, solid, particulate urea-based composition, thereby producing an effluent gas stream comprising urea-based dust particles and ammonia gas; (iii) in the effluent gas treatment section, treating the effluent gas stream from the particulation section comprising urea-based dust particles and ammonia gas with an aqueous solution to produce a scrubber solution; and optionally comprises one or more of the steps of: (iv) in the mixing section, if present, mixing the urea melt of 95 to 99 weight% of step (i) with other fertilizer components to produce a urea-based melt; and (v) in the scrubber solution storage section, if present, storing the scrubber solution from the effluent gas treatment section; (iv) in the mixing section, if present, mixing the urea melt of 95 to 99 weight% of step (i) with other fertilizer components to produce a urea-based melt; and (v) in the scrubber solution storage section, if present, storing the scrubber solution from the effluent gas treatment section; wherein the additive is introduced into the urea or urea-based composition as an aqueous suspension, an aqueous dispersion, or an aqueous liquid, by adding the additive to one or more of: (a) said effluent gas treatment section; and/or (b) said scrubber solution storage section containing the scrubber solution, if present. (a) said effluent gas treatment section; and/or (b) said scrubber solution storage section containing the scrubber solution, if present.