Four year old constant runny nose question

[Braden24]

To make this short and sweet we moved from a high desert area of the country (Santa Fe, NM) to New Orleans, LA. Our four year olds nose has ran no stop ever since the move 5 months ago. He is always sucking it up and it causes lots of coughing at night time because he hasn't quite learned how to blow it out and it drips in his throat and causes phlegm. Now that we are in a new environment with humidity etc how can we lessen his runny nose and phlegm he gets all the time now? I read somewhere that if he eats lots of dairy to cut that back etc but looking for more advice.

[Sharryn92]

It can be due to the new place you have moved my father inlaw went hunting in same kind of conditions for a few weeks and he ended up actually losing his sence of smell to this day he cant smell a thing and has bad allergies so maybe it's hayfever or allergies your littlw guy has