Wireless Monitoring for a Safe Indoor Environment

In striving for the construction of energy-efficient and cost-effective buildings, the imperative issue of the building's indoor air quality (IAQ) often is overlooked. This can lead to an unhealthy indoor environment and even to conditions such as sick building syndrome (SBS) or other building-related illnesses.

Poor IAQ is a major concern to businesses, building managers, tenants and employees because it can impact the health, comfort, well-being and productivity of the building occupants. This is especially important in industries where people spend a lot of time indoors. Many office workers, for example, will spend their entire working day inside a building. Healthy, comfortable employees invariably are more satisfied and productive.

While the measurement and monitoring of hazardous gases is a critical issue in industrial and workplace safety, often it has been concerned with acute levels of airborne pollutants. Today, there also are mounting concerns about the effect of long-term exposure to low levels of pollutants and to airborne pollutants found in office buildings.

POOR INDOOR AIR

In the past few decades, energy conservation measures have led to airtight building construction that can create problems with IAQ. Frequently, the ventilation systems are set to minimize the amount of fresh air entering and circulating within the building. This restriction impacts indoor air, allowing a build up of air contaminants within the building that are not properly removed.

There are many factors that can lead to an unhealthy indoor air environment, including poor or inadequate ventilation and airborne and chemical pollutants, emissions from printers and photocopiers, high concentrations of total volatile organic compounds (TVOCs), formaldehyde off-gassing and pollution from external sources (e.g. fumes) are just a few of the potential IAQ issues faced by employees.

When a substantial proportion of the occupants of a building experience symptoms associated with acute discomfort that usually are relived upon leaving the premises, the culprit can be sick building syndrome. The mechanisms still are not fully understood, but poor indoor air quality is thought to be a major contributor to these problems.

Health effects from indoor air pollutants may be experienced soon after exposure. The immediate effects usually are short-term and treatable, including irritation of the eyes, skin, nose and throat; upper respiratory congestion; headaches; dizziness; and fatigue.

Long-term exposure to low levels of pollutants could affect the exposed individual's health in future years. The U.S. EPA/Office of Air and Radiation reports that exposure to some indoor air contaminants can be severely debilitating and can result in respiratory diseases, heart disease and cancer. Exposure to high levels of some pollutants, such as carbon monoxide, can result in immediate death.

MONITORING INDOOR AIR

Typical indoor air quality investigation and examination consists of taking single-point measurements of pollutant levels. This monitoring method is unreliable, as the pollutant levels is subject to hourly, daily and even seasonal fluctuations. Building service professionals and designers alike have regarded these IAQ examination methods as being inadequate, considering today's environmental challenges.

A wireless monitoring system can ensure that almost any type of building is safe from the effects of poor IAQ. Continuous monitoring means the problems associated with single-point measurements are eliminated. The advances in technology have made it possible for a wireless system to control and monitor IAQ parameters continuously in real time. This has created a scientific approach to the systematic monitoring and management of any indoor air environment.

State-of-the-art gas sensors, automatic sampling, data logging, digital technology and IT have made it possible for IAQ profiling to be accurate and efficient and, therefore, a cost-effective system.

A wireless system enables simple, continuous detection and measurement of many of the factors that contribute to a building's indoor air environment, such as temperature, humidity and a number of toxic gases and compounds including carbon dioxide, carbon monoxide, nitrogen dioxide, sulphur dioxide, ozone, ammonia, formaldehyde and total volatile organic compounds (TVOCs).

The American Conference of Governmental Industrial Hygienists (ACGIH) publishes threshold limit values (TLVs) for these substances, which are defined as an exposure limit “to which it is believed nearly all workers can be exposed day after day for a working lifetime without ill effect.” The list of TLVs includes more than 700 chemical substances and physical agents, as well as dozens of biological exposure indices for select chemicals. Substances are nominated by the TLV committee of ACGIH based on new occupational exposure data or requests of government organizations, workers, industry, etc.