What Can Be Done to Tighten Pores Permanently?

I seem to have stubborn pores that are so responsive to the environment that I am in. When I get exposed to a hot and dusty and smoggy environment I notice my pores are larger, and I grow pimples and milia. When I'm in a cold temperature, they're a bit relaxed, but they don't close up. I do the usual routine, cleanse,tone, moisturize, and sunblock, but still, my pores don't close up. I am also concerned that open pores make me look old when looked upon closely (not in pictures). Please help. Tnx

No doctor answers yet