Monitoring of indoor air quality (IAQ) has become a concern of every health and safety professional. Since the energy crisis of the mid-1970’s, buildings have been designed for increased energy efficiency by decreasing the use of outside make up air. Such “tight” buildings recycle air that is already heated or cooled to the desired temperature. This recycling can cause chemical contaminant levels to concentrate inside the building. Many of these contaminants can be monitored quickly and cost effectively with the Sensidyne-Kitagawa detector tube system. Some of these substances are summarized below.

• Carbon monoxide and nitrogen oxides are products of combustion from sources like tobacco smoke and vehicle exhaust. Unventilated indoor smoking areas and indoor vehicle operation (e.g., parking garages or forklifts) can cause elevated levels.
• Formaldehyde is a traditional component of insulation foams and glues used in construction materials. Sources include urea-formaldehyde foam insulation, plywood, particleboard and imported carpeting.
• Carbon dioxide is a component of exhaled breath and can elevate in populated buildings. The level of carbon monoxide is often used as an indicator of the quality of indoor air. Fresh air contains about 350 ppm of CO2. The American Society of Heating Refrigerating and Air-Conditioning Engineers (ASHRAE) sets its indoor maximum CO2 level at 1000ppm.
• Ozone is formed when an open electrical spark contacts air. Ozone is produced naturally by lightning, and the ozone layer in our upper atmosphere is produced by UV radiation. It is a component of automobile exhaust. Sources of ozone indoors include photocopiers, scanners and electrostatic air fresheners.
• Ammonia is a common component in janitorial supplies like window cleaners. It is also emitted from old style blueprint copiers.
• Sulfur dioxide and hydrogen sulfide may enter the building from external pollution sources such as boiler stacks and power plants. Hydrogen sulfide can also form in untreated water wells and be emitted by lawn sprinkling systems. 
• Acetic acid, trichloroethylene, benzene, toluene, methyl ethyl ketone, alcohols and methacrylates are possible at lower levels from various sources such as caulking compounds, paints, cleaners, photocopiers and tobacco smoke

Detector tubes offer a fast and simple means to detect the above compounds. They are direct reading, which eliminates laboratory turn-around time. The powerless operation allows a detector tube system to go anywhere at any time. There are no batteries to charge and no electronic components to hamper intrinsic safety. The system is easy to operate for non-technical personnel with a minimum of training.

Some detector tubes useful in IAQ monitoring are listed in the table below:

 

Target Substance	Tube No.	Measuring Range
Acetic Acid	216S	1 to 50 ppm
Alcohols	119U	20 to 1000 ppm
Ammonia	105SD	0.2 to 20 ppm
Benzene	118SD	0.2 to 75 ppm
Carbon Dioxide	126SF	100 to 4000 ppm
Carbon Monoxide	106SC	1 to 50 ppm
Formaldehyde	171SC	0.05 to 4 ppm
Hydrogen Sulfide	120U	0.2 to 6 ppm
Methyl Ethyl Ketone	139U	20 to 1500 ppm
Methyl Methacrylate	184S	10 to 160 ppm
Nitrogen Dioxide	117SC	0.1 to 10 ppm
Ozone	182U	0.025 to 3 ppm
Sulfur Dioxide	103SE	0.25 to 10 ppm
Toluene	124SB	2 to 100 ppm
Trichloroethylene	134SB	0.2 to 16 ppm