Pollution can play havoc with your skin – irritating and prematurely aging it. But there are things you can do to combat it. Heather Stephen explains. The World Health Organisation claims air pollution is linked to one in eight deaths worldwide,  and pollution through cigarette smoke, exhaust fumes, wood burners and industry has been linked to a whole raft of diseases from dementia to heart disease to cancer. And it’s pretty disastrous for our looks too. Our skin is our largest organ and it bears the brunt of the daily assault our environment throws at us – prematurely aging and…