1. An image processing apparatus comprising: a processor; and a memory, the processor and the memory configured to function as: a derivation unit configured to derive parameters for white balance adjustment processing based on a transmittance of light incident on each pixel of captured image data including a fine particle component corresponding to fine particles suspended in the atmosphere when the image data is captured; and a generation unit configured to generate corrected image data of the captured image data by performing white balance adjustment processing on the captured image data to effect white balance adjustment of the captured image data using the derived parameters, and performing removal processing on the captured image data to remove the fine particle component from the captured image data using the transmittance, wherein the derived parameters are weights that reflect a pixel value of a pixel having a high transmittance more than the pixel value of a pixel having a low transmittance, wherein the removal processing includes: (i) referring to a plurality of pixels neighboring a pixel of interest to specify a pixel having a smallest average value of an RGB value out of the plurality of pixels; (ii) calculating a fine particle component of the pixel of interest by: (a) assuming a transmittance of the specified pixel is 0; and (b) multiplying a pixel value of the specified pixel by a value obtained by subtracting a transmittance of the pixel of interest from 1; and (iii) subtracting the fine particle component of the pixel of interest from a pixel value of the pixel of interest.