Smoke Detector Safety

Hello friends,

The smoke detector in my basement continues to go off, 2-5 times a day but only for a minute or less. This is not a CO2 detector. I investigate when he goes to be greeted by the same familiar smell of the basement and a sensor that immediately stops the alarm. What I mean by "familiar smell" is as follows:
I have a field stone foundation with lots of slots and a dirt floor. I also have an oil tank and old burner. The basement smells and dirt of the cellar and oil. (I have a sense of smell-sensitive).
I already changed the batteries (not working), then traded with another detector on the floor (got the same result). This tells me that the sensor is not defective.
I already called the oil company and they did an inspection of the tank and the burner and did not find any significant problems. They made sure all connections were tight and clean the burner door so it would flush. (Still have the problem)

Obviously with such a rustic basement, no one sleeps there or spend time. My room is on the 1st floor and the children are on the 2nd. There is no real evidence of smoke or fire. The basement has a good ventilation due to defects in the foundation, doors and windows.

I have several questions:
1. Do you know why the detector goes off?
2. Have you experienced this? What was the solution?
3. Should I be concerned about our safety? If the exhaust smoke, it is obvious that it is only building to a level that is evacuated quickly enough to prevent the alarm supported. What about CO2? Is CO2 instead?
4. Who else can I call or what to do? Should I call the fire department. to test or to get advice? I own my own house and I'm strapped up.

My first priority is the safety of my family. Secondary is finance, but which becomes a consideration if we are not in danger and not be angry.

Thank you for reading this broad question, I give these details in the hope that long to get good advice.

You did not mention the age of the detector. Being in a humid environment may shorten its life. You can get a good fire-X for less than $ 15. His guess the sensor is dirty, clogged or just the elderly. You could have swapped with another of the same age as most people to replace all at the same time. They work on the density of air, do not smoke. You may have other problems, including field stone, and dirt floors. It will probably quiet when you look because you have opened the door of the basement and let the problem. CO2 and methane alarms are relatively inexpensive, their first attempt.

I would say a professional service that tests air quality. Also, you sense carbon monoxide, I suppose, which is co no CO2 - which is carbon dioxide (what you exhale).