Find out what your triggers are ,things like pollen,dust etc. are greatly reduced at sea.If it's mold/mildew as in my case you must make war on it with a program that includes: constant ventilation below ,open lockers when off the boat ,constant attention to leaks
,dry bilges,non porous fabrics below,and special attention to the prevention of the accumulation of salt
below and in the cockpit
where bathing suits,foul weather gear
, etc.. will drag it and its hygroscopic properties into the living areas where the moisture will cause a huge increase in the spores.
I've been hospitalized from asthma but have been able to keep my boat mildew free without cramping a sailing lifestyle.You can pm me if your trigger is mildew for a more extensive dissertation