Carbon Monoxide - Carbon Monoxide is a colorless, almost odorless and tasteless gas or liquid. Carbon Monoxide can cause chest pain, fatigue, impaired vision, headaches, dizziness, confusion, nausea, flu-like symptoms and even fatal. Carbon monoxide usually comes from burnt gases (gas furnace, wood stove, gas water heater, gas stove, cars, buses & boats to name a few). It can be fatal and should be monitored by detectors in your home and can be found at your local department or home store. Yes vehicles and boats push it out their exhausts, so use caution in closed and
OPEN areas. Some people think just because you are in the garage with a car started and the door down you will have a problem. Swimming behind an idling boat can harm you.
http://www.epa.gov/iaq/co.html
Termites, Ants & other destroying organisms - When owning a home or buying a home it is important to protect against home destroying organisms. Termites and Ants are some of the most destructive, however not the only ones that can do damage. The easiest way to keep them out is to make it harder for them to get in. Keep wood from touching the ground to the house, don't store debris too close to the home or under, keep dirt away from all decks & fences and check your home for signs of infestation or deterioration. Your local termite & bug companies can help educate on what to look for, how to treat or how to be proactive and treat before infestation happens.
Formaldehyde Adhesives & VOC's Formaldehyde adhesives and VOC's - volitile organic compounds are used in several building materials (glues, paints, unvented fuel-burning appliances, fiberboard's and much more). Formaldehyde is yet another colorless however pungent-smelling gas. It may trigger asthma attacks, lung issues, allergies, allergic reactions, cancer and other issues.
For more information see:
https://www.epa.gov/indoor-air-quality-iaq/technical-overview-volatile-organic-compounds