That and you realize your only plugging the red channel into the opacity multiplier. Its multiplying the opacity of the particle color by the red channel of the UV texture. You either want the top or bottom pin unless you have a specific reason for that.
Loook at the dust particle system from the starter content for reference. They are HARD to see.
Don’t forget to accept an answer that best clears your question up or answers it so when the community finds your question in the future via search/google they know exactly what you did to fix it/get it going as well as keeping AnswerHub clean so that it gets removed from the “unanswered questions” category.
So your multiplying the ParticleColors opacity * the amount of data in the red color channel of the dust texture then putting that value in opacity. You should have either all color (red,green, blue) by using the top pin of the texture instead, or the opacity by using the bottom pin.