When you are outdoors working out, you need to wash your face afterwards. With the toxins that your body is releasing, along with sweat, urban pollution and even plant materials on the streets, that is a potion for clogged pores.
Be sure and use a nice, easy to rinse gel or foam to cleanse your face and if you are really feeling gross, you should cleanse your whole body and use a scrub.
I'd never thought of that before. With all the pollutants from vehicles and other, my face could probably use a good washing after a walk. I don't have naturally perfect skin (how many of us do?), so this is a welcome tip.