A method of reducing ammonia aerosol from manure is disclosed, which method employs an animal feed including a substantially indigestible cation exchanger capable of binding ammonium cations and an acidogenic substance to acidify an animal's manure and thereby create ammonium cations that can be bound by the cation exchanger. The method of feeding said animal feed reduces ammonia emissions from manure produced by animals fed the animal feed compared to the emissions obtained from manure when an acidogenic substance is fed alone and compared to the emissions obtained from manure when a cation exchange capacity material is fed alone.