"Is cooking in aluminum pans bad for you? I use them on the grill for vegetables."
Aluminum is the third most abundant element in the earth’s crust, and it is in the air, soil and plants we eat. It is found in far greater concentration in a single antacid than you are likely to get from food cooked in aluminum pans.
Having said that, you should be aware that highly acidic foods, like tomatoes, lemon, most fruits, vinegar and wine, absorb much more aluminum than others. These acidic foods, along with undissolved salt, can cause the surface of uncoated aluminum (whether a pan or foil) to pit, and therefore presumably cause additional leaching.
Grilling non-acidic vegetables on aluminum should not be a problem. Cooking on pans with aluminum in them but which are coated or anodized, is also not an issue, because the coating forms a barrier between the metal and the food.