Air quality  problems are usually caused by poor ventilation, high temperatures and humidity, coupled with the existence of bacterial, organic, chemical and mineral pollutants.

Asbestos is a generic term used to describe certain naturally occurring minerals found in the environment.  It is distinguished from other materials by the fact that its crystals form long, thin fibers which can be woven and used to strengthen other materials, but can also be inhaled into the lungs.

Carbon Monoxide , CO, is a poisonous gas produced when fuel burns incompletely.     

Cockroaches are now believed to be second only to lead based paint as a potential health risk to children in many urban areas.

Contaminated soil A large number of properties, world wide, now contain dangerous levels of hazardous substances (e.g., asbestos, carcinogens, dioxins, lead, pesticides, defoliants or radioactive wastes.)    

Fleas   A mong the reasons that many landlords prohibit pets is the odor and flea infestation that is often left behind by departing tenants. A bite to a new tenant checking out your unit can often cause intense itching and irritation.      

Lead based Paint   If you own four or more residential units, the federal government mandated that you begin disclosing known lead-based paint and lead-based paint hazards in your rental dwellings after September 6, 1996, and provide reports containing that information to all present and future tenants.
      Landlords also had to begin giving renters a federal pamphlet titled "Protect Your Family From Lead in Your Home." Home sellers and owners of less than four units are subject to the same regulations beginning December 6, 1996. 

Mold   Some species of mold spores can be highly toxic and dangerous to humans , particularly Stachybotrys Chartarum .

Radon is an element that generates radioactivity. It is a naturally occurring gas that cannot be smelled, seen or tasted and that is sometimes found in excessive quantities in the soil.

Termites  can be likened to cows, "micro-bovids" or "mini-ruminants", since they have a hugely modified, multi-compartmented gut, for digesting a cellulosic diet , which may include any wood portion of your building.   

Resources

Office of Prevention, Pesticides and Toxic Substances (EPA) Information, Rules, Regulations, and Legislation.

The above topics are discussed in much more depth
on our members' Environmental Issues page.