Yes, I believe that an individual can be allergic to foreign pollen, dust, and allergens from a different area, because a person who is not from the area has not had time to let their body build up defense systems. If someone is used to an allergen, their body can find ways to cope.
Our allergies can be extended far into our genetic past. I am not from Florida and my relatives are from Canada. I wouldn't be surprised if I was allergic to agents in that region. The fact is the allergies have to come from somewhere, even if that's 10 generations in the past.
I definitely think that a person can be allergic to foreign pollen, dust, and allergens from a different area. Just because somebody may not be allergic to some of the allergens in their homeland, doesn't mean they will react that same should they go overseas. I know a few people who have actually experienced this.
You can develop allergies no matter where you go in the world. I have had it happen to me in a few different countries in different regions of the world. It happened in India and Thailand in the eastern part of the world. And in the west it happened in Brazil, the US, and Canada
It is my understanding that allergies develop over a period of exposure to various types of allergens. Therefore a foreign pollen, dust, or allergens from a different area are not likely to cause someone allergies unless they are exposed for a number of years. In short, I disagree that foreign allergens can cause allergies in someone not of that area.