Home air/cleaning help?

We've had air quality alerts throughout the city. There's been extreme heat (hundreds) with nights in the 90's, sometimes the higher eighties. Then after a good time of drought, we got torrential rain (praise for that) but now my one daughter, who never has any health problems, keeps catching her breath and coughing. My husband is starting with similar issues and has asthma. I believe the cause for this is a variety of factors, but my main concern is that the rain combined with the temps is producing mold.

I think if I do a thorough job of cleaning it will help, but my problem is the air conditioning vents. During the drought we started having strange little bugs coming through them in mass numbers. My one daughter looked it up online and found they typically come through air conditioning vents and yep, that's where they came from! I mixed bleach and water in a spray container and sprayed them and it worked, but I think the air coming through is still messed up and the solution, while it worked for a few days, had to be repeated yesterday. I don't like using bleach like this in the home (on surfaces where it can't be washed off) but to make sure there's no mold problem, I'm going to be bleaching and sanitizing all over the place when we're done at church today. Any advice on doing a thorough job and places I may not think of would be helpful or advice on what could do the same job without the harsh chemicals.

The next issue is to try to purify the air in here. At this point I can't afford to run out and buy an air purifier. Do you know of anything simple I can do in the home that can help with air quality? We do have green plants inside, obviously that's not enough in and of itself. I'm wondering if there are any plants/spices that could be boiled on the stove that are known to cleanse the air? Also, would there be any herbal supplements or the like that would help hubby and daughter to cleanse their airways? For viral type things, I usually make tea from osha root and sometimes mix it with garlic, lemon and honey, but don't think this would have much to do with breathing.

If you have knowledge on this topic, please share!

 

There's definitely going to be an air purification system in our future, but today I'm looking for a temporary fix until that future time arrives.

You may be right about the mold. I'm not seeing much of it, save for the rims of the deep freeze, which I emptied out and sanitized last night. There was mold on the sealing that runs around the lid to keep it air-tight.
Then again I haven't looked everywhere yet, but the fact that it happened after the rain put that suspicion in my mind.