It entirely depends upon how much you sweat in a day. It also depends upon your type of work. If it is in a very warm or hot place or if you are work in a dusty atmosphere you will likely to get lots of dust like this. Avoid using synthetic wears, and heavy clothes and use only cotton inner wears and use talcum powder freely in your flexural areas like axilla
, under breast, neck etc. Use skin friendly talcum powders. Avoid using tight dress continuously for long hours. You will feel better.