I'm not sure what the issue could be. . . do you have forced air heating? Perhaps you could try putting a humidifier down there when people will be sleeping to see if that helps. ..

I'll try a humidity gage, but I'm pretty sure that is no the problem.

Does the "off gassing" go away? Is this something that can be measured? Can we figure out what it is? Is there some sort of service that I can call?

My first thought was the off-gassing of all the new materials you've put in the basement. When DS had their floors refinished a few people couldn't enter the house without sneezing and coughing. Luckily they didn't live in the house at the time so we kept the house open and well ventilated. All symptoms stopped after 2 weeks. Until you know more I'd suggest opening up the area as much as possible and get lots of air flow going.

The site below shows info for the state of Wa. for Environmental Health. Maybe you can contact the same dept. for your state.

Here is a link that might be useful: Air quality

I'd get the humidity gauge just because you want to eliminate that as a factor one way or the other (too high or low). They are super cheap, $10 I think.

In our case the offgassing went away, I think it took about 6 months. I woke up everyday with a congested nose and itchy sore throat. My head felt "thick". As far as I know offgassing can't be measured. Some people are affected by it, other's aren't. I would think that how long it takes will depend on what materials you use and how tight the space is. Tile doesn't offgas, wood floors and carpet do. Some paints do. Cabinets do. We moved in during the winter, so I'm sure that made it worse because the house was closed up. I would keep the windows open, use a fan to direct air in through one window and another fan to push air out through another window.

I don't think the air is dry, I think its damp-- most basements are-- and you have mold issues. If the humidity is fine down there now, have there been floods or leaks that saturated wall board, carpet, joists or studs in the past? The mold can be dormant, but the spores still circulate in the air.

Fungus exudes poisons called mycotoxins intended to keep other lifeforms at bay [penicillin, for example]. These often leave our throats scratchy and heads stuffed, often with a general feeling of overall malaise.

Next time someone sleeps down there, have them leave the window open as far as possible, even place a fan on the window sill to draw fresh air in, diluting the concentration of spores.

I think fungus will be THE health issue of the next 50 years. There are no simple tests for fungal infections, so science is only just beginning to understand how widespread and devastating they are.

Two things come to mind:
1. Dust, especially insulation. Do you have any old pipe insulation with asbestos? I was working in our attic the other day working up some fiberglass dust, and it caused my daughter to cough in the living room - this was just from a little dust filtering down through the access hole.

2. Ozone, O3. Is your furnace or other sparking appliance generating ozone? Also, a photocopier, used a lot, will generate quite a bit of ozone. The smell is what you normally notice around a photo copier. Ozone will give you a scratchy throat - it attacks your throat lining, oxidizing it, and in the process is converted to regular old oxygen. You also smell ozone right after a thunderstorm. In small amounts, it is a good air freshener, in moderate amounts it causes dry throats and headaches, in large amounts it is deadly - although you don't find it in large amounts since it is so reactive it quickly dissipates by oxidizing organic substances and thus reducing itself to ordinary oxygen, O2.

I agree that this is a mold issue. Have the air tested and find out what the percentages are. They sound high if there is throat irritation that quickly. Understand in advance that mold can be very dangerous to anyone with compromised upper resporitory systems, like asthma. My brother in law was hospitalized for three weeks with a reaction to mold in the condominium that he had just purchased. The previous owners had painted over sheetrock that was damaged by a roof leak. When they removed the sheetrock the entire wall was covered with mold and needed professional mold abatement.

I agree I'd consider mould and/or dampness over dryness, and also agree fumes from building materials are another possibility, also, apart from ozone, what about oxygen content and/or co/co2 levels?

There has been lots of controversy about 'mould inspectors' a lot of the so-called ones are not qualified, I think you should get some sort of expert to look at it for you, there may even be some sort of government agency that can assist, although if you didn't put that downstairs room in with a permit, you may not want to involve govt officials.....

I'd place bets on mold and the easiest way to know is to purchase a home test. They are inexpensive and you're not hiring someone who has a vested interest in finding mold in order to get the remediation contract. The home test mold kits can be found on-line or sometimes at a hardware store. You open the dish, leave it in the space for a certain period of time, put it in an envelope and send it in to the lab. They return your test results. If people are coughing, it's my guess they are reacting to mold spores, and it's not about dryness, especially in a basement that's partially below-grade. Whatever you do, DON'T get a humidifier as you'll just make the problem worse.

The other simple inspection you can do on your own is to remove baseboard from sheettock, esp. on the earth-side of the space and see if you can notice and greying of the sheetrock or the basebboard itself. If you do, then pull some sheetock off and look behind it.

Good luck.

Here's what I found on the Center for desease control site.

"I found mold growing in my home, how do I test the mold?
Generally, it is not necessary to identify the species of mold growing in a residence, and CDC does not recommend routine sampling for molds. Current evidence indicates that allergies are the type of diseases most often associated with molds. Since the susceptibility of individuals can vary greatly either because of the amount or type of mold, sampling and culturing are not reliable in determining your health risk. If you are susceptible to mold and mold is seen or smelled, there is a potential health risk; therefore, no matter what type of mold is present, you should arrange for its removal. Furthermore, reliable sampling for mold can be expensive, and standards for judging what is and what is not an acceptable or tolerable quantity of mold have not been established."

I'm not sure if I should test, or just try to get rid of what I see on the cinder block. Does anyone have experience with a test kit? Can you recomend one?

Another posible problem could be my paints. I am a decorative painter,(I do murals, polished plaster, glazing, etc.)At this point, I work with mostly water based paints. I have a lot of paint stored in the back, but it's all in sealed containers. I read somewhere that stored paints could be a problem. How can that be, if they are sealed?

Is the mold showing up on painted, interior cinderblock?

Honestly, I don't trust the CDC too far in this respect. The government agencies are traditionally about a decade [or two] behind the cutting edge-- witness the 'food pyramid' that encourages people to eat lots and lots of carbs.

The problem with mold is that it basicly can't be seen in the body without very expensive testing. A lot of medical professionals consider it akin to voodoo, much as they once rejected Pasteur's germ theory. Absence of evidence is not evidence of absence, if the evidence is practically invisible and almost no one is looking for it. There is some evidence that fungus is implicated in certain cancers, as well as other devasting illnesses like Crohn's.

I'd go ahead and test, if you can find a kit from a source with no vested interest-- since your home is making people ill, this is not 'routine sampling'.

I really don't think your paint is the issue, if its properly stored. You could check the lids, make sure they are very tight, but they shouldn't be outgassing unless they are drying.

annz, I'm glad you asked about the mold showing up. I was going to tell you that I saw no evidence of mold, then I thought, let me make sure. I went to the cinderblock walls in the unfinished part of the basement with a flashlight.

I thougth that I solved the water seeping in when I graded. I looks like I didn't. there is evidence of new wetness in spots. There is very little water, it's just damp spots. There is white effovecense on the cinderblock, but no sign of mold, that I can recognize, nothing black.

I don't think the cinderblock areas are where you need to be concerned. Mold needs food, and food takes the form of wood or paper backed sheetrock. I would check areas that have these "food sources". The efflurescence in the cinderblock does suggest some moisture intrusion, but that's not uncommon, it can happen with almost no actual water.

The other culprit could be older furniture that has mildew. My nephew used to visit and sleep on my mother's couch and get very sick with upper-respiratory "colds" until we realized that the couch was extremely dusty and dank and probably had mildew. Now we cover it and it's not a problem.

I agree with the mold and fungus suggestions. Remove any food source and maintain dry conditions and the little critters will not produce spores. Thorough cleaning will also help.

I am mildly allergic to a particular mold that occasionally blooms in a church parsonage basement. Since installing a dehumidifier, the mold has gone dormant and I no longer have symptoms.