My wife has asthma and does respiratory work at the hospital. Heres what we know. By the way, there is a lot of anecdotal "evidence", funny stats and studies, and some things work for some people and not others. Further, sometimes people feel something works for them when it really doesnt. A case in point...theres a particular air purifier thats very expensive and has been shown to do absolutely nothing to clean the air, but people who buy them will hunt you down and kill you if you say the product is ineffective because it has "changed their life". So on with the controversy...
My wife had been taking the range of "old school" asthma drugs because thats what the doctor and insurance company wanted her to take. She changed two years ago to advair and since then despite three dogs, three cats, and wall to wall that usually needs vacuuming, she has almost no symptoms. Bearing in mind she was good for 2-3 trips to the emergency room per year up until then, and suffered with it since she was a small child.
The basics are simple: stop allergens from entering the home, remove them if plausible, stop them from coming near the baby's nose, clean the baby's nose a couple of times a day to remove allergens, use decent meds to mitigate the allergies/asthma that remains...a lot of people do the meds and throw in an air filter and figure they're doing great...
Air purifiers are all well and good, but the majority of them dont do much, they arent localized enough (in other words, you dont wear them under your nose), they suck down a lot of electricity, and there are few businesses with as much funny business going on. Some advertise a 'filter that removes 99.99%' when in fact the filter does so, installed in the air cleaner with gaps around the filter, its more like 65 or 75%. Further, you have to get the dirt to the air filter. We have used some of the hamilton beach units with the UV light. They're inexpensive, the filters last forever (4 years later we still havent done more than take the prefilters outside and vacuumed them), and the UV light allegedly destroys mold spores and some bacteria, a claim which seemed to be borne out when my wifes allergies improved after 30 days of continuous use...the time period it takes for the unit to destroy enough mold spores to affect the dust mite population (dust mites primarily eat mold spores).
Duct cleaning has been shown over and over again to be nearly worthless. Its a snake oil treatment. Think twice about those "furnace air filters". There isnt much outside of the filter manufacturers but I did see a couple of HVAC guys who published their own evaluations on their web sites. Basically the furnace doesnt run long enough to effectively filter the air, there are gaps around the filter and in the unit that allow unfiltered air through, and either your furnace fan will kick into a higher gear to overcome the higher air resistance or the temps in the furnace may increase to the point where the heat exchanger cracks. Happened to me with a 5 year old furnace in my old mcmansion and the heating repair guy fingered the filter. Even the higher flow filtretes put a huge drag on the air flow. The fan kicking into high gear isnt a lot of fun either, mine uses 500+ watts on the regular setting and jumps to 800+ on the higher setting.
Dont go for the "money=performance" either. Most of the "whole house filtration" units sold through specialty allergy sites for $600-1000 are middling performers with very expensive filtration units.
What does work:
- Get the best meds available. According to my wife advair is the best for moderate to severe asthma, although you have to inhale a powder from a dispensing disk. She says some small kids and older folks cant figure out how to use it...they try blowing into it or sucking on it. Your friendly doctor may also try to follow insurance guidelines and give you singulair or theophylline as they're cheaper "old school" drugs.
- Get a prescription for a nebulizer and the drugs required to administer a breathing treatment. Its a small device with a mask, you put the albuterol or xopenex (newer) or pulmocort into it, put the mask on her face and after a few minutes this will alleviate a minor to moderate attack and avoid a trip to the emergency room.
- Change bedding regularly. The pillow and mattress covers are fine but you might want to spend some time and money looking into allergen resistant bedding. Some latex mattresses, pillows and some memory foam products are highly allergen resistant. There are a number of outfits that sell online and over ebay that sell these products at discount, so you can "roll your own" allergy proof bed vs spending a couple of grand on one.
- Carpet can be problematic, but so can hard floors. If you dont vacuum nearly every day, a carpet may hold onto dust and other allergens and prevent them from becoming airborn a lot better than a hard floor. On the other hand, if you have mostly hard floors something like a Roomba can be used to pick up most of the crud on a daily basis. Once a carpets been down a long time though, its gonna be an allergy problem. Consider a berber or other low/no pile carpet, go inexpensive and anti-allergen if available, make sure the pad is a low VOC sealed pad, not one of the cheap ones that powders, and change the carpet every 4-5 years tops.
- The laminate stuff goes down pretty easy once you get the hang of it. You'll spend the first two hours or so cursing and then you'll have it down and it'll go down pretty quick. I'd give specific advice but every product is a little different. My father in law is a retired flooring guy and i've done some of it with no problems, so if you have questions or get in trouble, let me know.
- Humidity can be your biggest problem. Humidity levels over 40-45% can cause mold growth and all sorts of other problems. Keeping the humidity level around 40% reduces mold spread and can improve breathing quality.
- Allergens stick to hair best of all. If she's been outdoors or playing on the floor, wash her hair. Some people have had dramatic improvements in allergy and asthma related conditions simply by washing their hair twice a day. Consider someone who uses a sticky hair "product", collects allergens all day, lays their head on thei pillow and over the course of the next couple of hours wipes the allergens off the pillow and then sticks their nose in it.
- Nasal "irrigators" are a no-drug option that can work wonders. From a simple rubber bulb filled with saline to a thing that looks like a waterpik (and you can get an attachment for a waterpik you already have) that clears the nasal passages. Just tipping your head sideways in the shower and using your hand to direct a little water and spray into your nostrils and then blowing can remove a lot of the collected allergens from your schnoz. Tough to administer to a baby or small child though. I have moderate allergies and clearing the nose in the shower and rinsing my hair before I go to bed during allergy season completely eliminates most of my symptoms.
Chasing the dust monster can really be a red herring unfortunately. Its almost impossible in a house full of VOC emitting products, cracks and seams to keep a highly "clean" environment.
Any other questions, ask away...between my wife, my mother in law who is a charge nurse and took care of my wife all her life, and our collected experiences in trying to improve her condition...we should have plenty of answers.
Edit: on filters that might help a little bit at a low cost, I have seen but not tried a "poor mans" air filter. Get a 20" energy star box fan that has the switch and electric cords on the top/bottom/sides (not in the middle of the front or the back) and duct tape a 20" filtrete filter to the intake side. Turn on. This will process as much air as your furnace, continuously, and at a very low cost. With as much or better efficiency as air "purifiers" that cost 20x as much. Dont expect a huge improvement from air filtration though...