What Skin Problems Are Men Usually Affected With?

Dear Sir or Madam,
I am a design student trying to develop a new shower gel and I am looking for a niche and was wondering if you could help me by answering the following questions.
what are the most common male skin problems?
what are the most common treatments?
does city pollution cause skin problems an if so what are they and how are they treated?
what are the most common sport related skin problems and treatment?
Are there seasonal skin problems if so what is the most common for summer and winter and how are they treated?

Thank you for your help

Dan