The Air We Breathe – Part 2

This two-part article examines indoor air quality, its health effects, its common sources, and how we can improve the quality of the air we breathe indoors. Part 1 provides an overview of indoor air quality, its main pollutants and common sources. Part 2 discusses the health effects of indoor air quality and what we can do to mitigate the ill effects of poor air quality. – Ed.

By John E. Jernstad
Mount Kisco, NY

Effects of Indoor Air Quality

The health concerns of poor indoor air quality (IAQ) are numerous and diverse, ranging from discomfort to irritation to chronic diseases. Common effects include odor; irritation of eyes, nose and respiratory organs, and skin; neurological symptoms such as nausea, dizziness, headache, fatigue and loss of concentration; immunological reactions including inflammations and allergic reactions; cancer; and an overall susceptibility of various disorders as well as aggravation of preexisting conditions such as asthma[2]. These are also the symptoms most commonly cited by those who suffer from the so-called “sick building syndrome” or “new house syndrome”.

Evidence from various studies have linked long-term exposure to indoor air pollution with several respiratory illness, with indoor air pollution accounting for more than 34% of the global burn of disease as measured by the disability-adjusted life-years lost[2]. While short-term reactions may be immediately observable and treated, often by removing the source of the pollutant, long-term effects may not become evident until the patient is exposed to harmful indoor pollutants for many years and is crippled by cancer or other debilitating diseases. The issue is further complicated by other variable factors including the level of pollutants, the length of exposure, and most importantly the sensitivity to IAQ for each individual person due to differences in age, general health, allergies, and other factors.

In addition to the direct health effects of IAQ, a less-addressed but nevertheless serious area of concern is the loss of performance and productivity due to poor IAQ in commercial and office spaces. A study[7] found that poor IAQ in buildings can lower the productivity of standard office activities by as much as 6-9%. By controlling the IAQ of both laboratories set up as simulated work areas as well as real business offices and using a control set of circumstances including quantifiable “work” such as typing and dictating, the researchers found that IAQ impacted both the perception (“the air smells bad”) and reaction (headaches, nausea) of subjects as well as the measured levels of productivity.

Identifying, Monitoring and Controlling IAQ

With such strong links between IAQ and overall health, wellness and even work performance, one naturally feels the need to explore options for controlling indoor air quality. The first step is to identify the problem. It must first be noted that common symptoms of poor IAQ, such as headaches, runny noses, and respiratory problems are also symptoms of the common cold or other viral diseases. The timing of the onset of these symptoms should be determined to see if they appeared following a move into a new residence or the introduction of new equipment or materials in an office [1]. Thus, rather than waiting for symptoms to appear, it would be more proactive to find possible sources of harmful gases and pollutants, such as new paint, office machinery, and other possible sources listed in the earlier section of this article. The occupant can also check for signs of poor IAQ and ventilation, such as molds, spots, or dirty and stale smelling air.

In order to better identify IAQ problems, users of residential and commercial spaces must monitor IAQ to both measure the amount of pollutants in the air as well as try to establish a real link between IAQ and the negative health symptoms being experienced by users. Some monitoring is basic, such as CO sensors that should be in every home or office or radon “do-it-yourself” detection kits that can be easily purchased online or in stores.

After identifying the source and measuring the level of pollutants in the air, the final step is to address the IAQ issues. There are three primary ways for dealing with poor IAQ: managing the source, putting into place better ventilation, and active cleaning of the indoor air.

Managing the source can often be the most effective solution for maintaining IAQ[1]. Radon emission can be controlled by checking the building site and removing subsoil with high radon levels, using supporting columns and high-quality mortar and concrete, and various types of sealers available in the market. Modification of exiting homes can use barriers and sealants made from non-permeable materials to seal cracks and prevent radon from seeping into the house, and installing ventilation systems to remove contaminated air from inside the home.

In addition, there are several steps for reducing VOC levels inside the home. Consumers can elect to use building materials and products with low VOC impact, precondition materials before construction and use, ventilate the building before and after the installation of new products (a seven-day “flushing” period is recommended”[1]) and checking to make sure that VOC levels are stable before using any newly-construction space. Users can also take caution in selecting pesticides, household cleaners and other products in order to control VOC levels. Instructions on packaging should be closely followed, and any mixing or application should be done outdoors whenever possible.

With harmful pollutants already present in the air, source management will not provide a short-term solution. In this case, ventilation will allow outdoor air to dilute indoor air pollutants, and remove them by venting them into the outside air. Ventilation can be both natural, using windows and taking advantage of advanced construction techniques, and mechanical, using fans, ducts and other systems to circulate and ventilate the air. However, ventilation has been found to be less effective for VOCs and other pollutants released form indoor sources[1].

The third method is active air cleaning, either through physical or chemical means. For example, radon gas can be removed using activated carbon (AC), although the amount of AC needed may be too large to be practical for some applications. The particles that are emitted when radon gas breaks down, on the other hand, can be removed by particulate matter control devices. In short, different types of active air cleaners are used for different pollutants, and the consumer must take care to identify the main source and type of pollution indoors and use the most effective and suitable type of device.

Air cleaners are generally classified by unit size, cleaning method and target pollutants. Cleaners for particulate matter employ mechanical filters that form barriers as well as electronic systems such as electrostatic precipitators, or ESPs. One of the most common types of electronic air cleaners, ESPs filter indoor air by charging the intake air using ionizing wires and collecting these charge particles on metal plates. While common, these units must be cleaned in order to stay effective and have been found to unintentionally produce ozone[1], a pollutant itself. Other air cleaners use chemicals to absorb contaminants, or absorption beds made from AC or other materials. AC is especially effective due to its ability to destroy ozone and other oxidants such as peroxides[8].

With people today spending the bulk of their lives indoors, IAQ is one of the most important environmental factors that directly impact health and wellness. While many cities around the world have large electronic billboards to announce the day’s outside air quality, not enough people pay attention to IAQ and its effects. Both residential and commercial spaces should be evaluated based on IAQ. Users themselves should check if they are developing any symptoms of poor IAQ, and work with building managers to identify sources of pollution indoors and try to implement the most effective measures. While nipping the IAQ problem at the bud by using building materials with low VOC-emission properties would be ideal, most people find themselves already in houses or offices that have been built without much consideration paid for IAQ. By being able to identify symptoms of poor air quality and recognizing some common sources of pollutants, everyone can begin drawing attention to the importance of IAQ management.

1. Oanh, N.T.K. and Y.-T. Hung, Indoor air pollution control. Handbook of environmental engineering, ed. L.K. Wang, N.C. Pereira, and Y.-T. Hung2005, Totowa, N.J.: Humana Press. xviii, 526 p.
2. John Wiley & Sons. and Retcaco Inc., Kirk-Othmer encyclopedia of chemical technology, 1987, Wiley,: New York, NY.
3. Ayres, J.G., Health effects of gaseous air pollutants. Issues in Environmental Science and Technology: Air pollution and health, 1998. 10: p. 1-20.
4. EPA, An introduction to indoor air quality (IAQ): Volalite organic compounds (VOCs). Basic Information on Pollutants and Sources of Indoor Air Pollution, 2011.
5. Harrison, P.T.C., Health effects of indoor air pollutants. Issues in Environmental Science and Technology: Air pollution and health, 1998. 10: p. 101-125.
6. Kodama, A.M. and R.I. McGee, Airborne Microbial Contaminants in Indoor Environments. Naturally Ventilated and Air-Conditioned Homes. Archives of Environmental Health, 1986. 41(5).
7. Wyon, D.P., The effects of indoor air quality on performance and productivity. Indoor Air, 2004. 14(7): p. 92-101.
8. Godish, T., Indoor environmental quality2001, Boca Raton, Fla.: Lewis Publishers. 461 p.