Indoor Air Pollution and Health

Indoor Air Quality (IAQ) refers to the air quality within and around buildings and structures, especially as it relates to the health and comfort of building occupants. Understanding and controlling common pollutants indoors can help reduce your risk of indoor health concerns.


Health effects from indoor air pollutants may be experienced soon after exposure or, possibly, years later.

Immediate Effects


Some health effects may show up shortly after a single exposure or repeated exposures to a pollutant. These include irritation of the eyes, nose, and throat, headaches, dizziness, and fatigue. Such immediate effects are usually short-term and treatable. Sometimes the treatment is simply eliminating the person's exposure to the source of the pollution, if it can be identified. Soon after exposure to some indoor air pollutants, symptoms of some diseases such as asthma may show up, be aggravated or worsened.


The likelihood of immediate reactions to indoor air pollutants depends on several factors including age and preexisting medical conditions. In some cases, whether a person reacts to a pollutant depends on individual sensitivity, which varies tremendously from person to person. Some people can become sensitized to biological or chemical pollutants after repeated or high level exposures.


Certain immediate effects are similar to those from colds or other viral diseases, so it is often difficult to determine if the symptoms are a result of exposure to indoor air pollution. For this reason, it is important to pay attention to the time and place symptoms occur. If the symptoms fade or go away when a person is away from the area, for example, an effort should be made to identify indoor air sources that may be possible causes. Some effects may be made worse by an inadequate supply of outdoor air coming indoors or from the heating, cooling or humidity conditions prevalent indoors.


Long-Term Effects


Other health effects may show up either years after exposure has occurred or only after long or repeated periods of exposure. These effects, which include some respiratory diseases, heart disease and cancer, can be severely debilitating or fatal. It is prudent to try to improve the indoor air quality in your home even if symptoms are not noticeable.


While pollutants commonly found in indoor air can cause many harmful effects, there is considerable uncertainty about what concentrations or periods of exposure are necessary to produce specific health problems. People also react very differently to exposure to indoor air pollutants. Further research is needed to better understand which health effects occur after exposure to the average pollutant concentrations found in homes and which occurs from the higher concentrations that occur for short periods of time.

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Volatile Organic Compounds' Impact on Indoor Air Quality



Volatile organic compounds (VOCs) are emitted as gases from certain solids or liquids. VOCs include a variety of chemicals, some of which may have short- and long-term adverse health effects. Concentrations of many VOCs are consistently higher indoors (up to ten times higher) than outdoors. VOCs are emitted by a wide array of products numbering in the thousands.


Organic chemicals are widely used as ingredients in household products. Paints, varnishes and wax all contain organic solvents, as do many cleaning, disinfecting, cosmetic, degreasing and hobby products. Fuels are made up of organic chemicals. All of these products can release organic compounds while you are using them, and, to some degree, when they are stored.


EPA's Office of Research and Development's "Total Exposure Assessment Methodology (TEAM) Study" (Volumes I through IV, completed in 1985) found levels of about a dozen common organic pollutants to be 2 to 5 times higher inside homes than outside, regardless of whether the homes were located in rural or highly industrial areas. TEAM studies indicated that while people are using products containing organic chemicals, they can expose themselves and others to very high pollutant levels, and elevated concentrations can persist in the air long after the activity is completed.

Sources of VOCs


Household products, including:

  • paints, paint strippers and other solvents

  • wood preservatives

  • aerosol sprays

  • cleansers and disinfectants

  • moth repellents and air fresheners

  • stored fuels and automotive products

  • hobby supplies

  • dry-cleaned clothing

  • pesticide


Other products, including:

  • building materials and furnishings

  • office equipment such as copiers and printers, correction fluids and carbonless copy paper

  • graphics and craft materials including glues and adhesives, permanent markers and photographic solutions.

Health Effects


Health effects may include:

  • Eye, nose and throat irritation

  • Headaches, loss of coordination and nausea

  • Damage to liver, kidney and central nervous system

  • Some organics can cause cancer in animals, some are suspected or known to cause cancer in humans.


Key signs or symptoms associated with exposure to VOCs include:

  • conjunctival irritation

  • nose and throat discomfort

  • headache

  • allergic skin reaction

  • dyspnea

  • declines in serum cholinesterase levels

  • nausea

  • emesis

  • epistaxis

  • fatigue

  • dizziness


The ability of organic chemicals to cause health effects varies greatly from those that are highly toxic, to those with no known health effect.


As with other pollutants, the extent and nature of the health effect will depend on many factors including level of exposure and length of time exposed. Among the immediate symptoms that some people have experienced soon after exposure to some organics include:

  • Eye and respiratory tract irritation

  • headaches

  • dizziness

  • visual disorders and memory impairment


At present, not much is known about what health effects occur from the levels of organics usually found in homes.

Levels in Homes


Studies have found that levels of several organics average 2 to 5 times higher indoors than outdoors. During and for several hours immediately after certain activities, such as paint stripping, levels may be 1,000 times background outdoor levels.

Steps to Reduce Exposure

  • Increase ventilation when using products that emit VOCs.

  • Meet or exceed any label precautions.

  • Do not store opened containers of unused paints and similar materials within the school.

  • Formaldehyde, one of the best known VOCs, is one of the few indoor air pollutants that can be readily measured.

    • Identify, and if possible, remove the source.

    • If not possible to remove, reduce exposure by using a sealant on all exposed surfaces of paneling and other furnishings.

  • Use integrated pest management techniques to reduce the need for pesticides.

  • Use household products according to manufacturer's directions.

  • Make sure you provide plenty of fresh air when using these products.

  • Throw away unused or little-used containers safely; buy in quantities that you will use soon.

  • Keep out of reach of children and pets.

  • Never mix household care products unless directed on the label.


Follow label instructions carefully.


Potentially hazardous products often have warnings aimed at reducing exposure of the user. For example, if a label says to use the product in a well-ventilated area, go outdoors or in areas equipped with an exhaust fan to use it. Otherwise, open up windows to provide the maximum amount of outdoor air possible.


Throw away partially full containers of old or unneeded chemicals safely.


Because gases can leak even from closed containers, this single step could help lower concentrations of organic chemicals in your home. (Be sure that materials you decide to keep are stored not only in a well-ventilated area but are also safely out of reach of children.) Do not simply toss these unwanted products in the garbage can. Find out if your local government or any organization in your community sponsors special days for the collection of toxic household wastes. If such days are available, use them to dispose of the unwanted containers safely. If no such collection days are available, think about organizing one.


Buy limited quantities.


If you use products only occasionally or seasonally, such as paints, paint strippers and kerosene for space heaters or gasoline for lawn mowers, buy only as much as you will use right away.

Keep exposure to emissions from products containing methylene chloride to a minimum.

Consumer products that contain methylene chloride include paint strippers, adhesive removers and aerosol spray paints. Methylene chloride is known to cause cancer in animals. Also, methylene chloride is converted to carbon monoxide in the body and can cause symptoms associated with exposure to carbon monoxide. Carefully read the labels containing health hazard information and cautions on the proper use of these products. Use products that contain methylene chloride outdoors when possible; use indoors only if the area is well ventilated.


Keep exposure to benzene to a minimum.


Benzene is a known human carcinogen. The main indoor sources of this chemical are:

  • environmental tobacco smoke

  • stored fuels

  • paint supplies

  • automobile emissions in attached garages


Actions that will reduce benzene exposure include:

  • eliminating smoking within the home

  • providing for maximum ventilation during painting

  • discarding paint supplies and special fuels that will not be used immediately


Keep exposure to perchloroethylene emissions from newly dry-cleaned materials to a minimum.


Perchloroethylene is the chemical most widely used in dry cleaning. In laboratory studies, it has been shown to cause cancer in animals. Recent studies indicate that people breathe low levels of this chemical both in homes where dry-cleaned goods are stored and as they wear dry-cleaned clothing. Dry cleaners recapture the perchloroethylene during the dry-cleaning process so they can save money by re-using it, and they remove more of the chemical during the pressing and finishing processes. Some dry cleaners, however, do not remove as much perchloroethylene as possible all of the time.


Taking steps to minimize your exposure to this chemical is prudent.

  • If dry-cleaned goods have a strong chemical odor when you pick them up, do not accept them until they have been properly dried.

  • If goods with a chemical odor are returned to you on subsequent visits, try a different dry cleaner.

Standards or Guidelines


No federally enforceable standards have been set for VOCs in non-industrial settings. To learn more about VOC's, including current guidelines or recommendations set by various organizations for formaldehyde concentrations, visit Lawrence Berkeley National Laboratory’s Indoor Air Quality Scientific Findings Resource Bank.               


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Cashins & Associates Blog 

VOCs and Indoor Air Quality


Posted byEileen Watkins on Mon, Apr, 14, 2014 @ 21:04 PM

If you're researching or discussing indoor air quality, chances are you'll read and hear a lot about VOCs.  What are they, exactly, and where do they come from?  Do they affect indoor air quality?  Are they harmful?  This article will help answer some of those questions.


In order for a chemical to be classified as a VOC, it must meet 2 basic criteria - it needs to be classified as an organic chemical and it must exist as a vapor at room temperature.  The acronym TVOC stands for total volatile organic compounds, or the sum of all the VOCs in a space.  While VOCs and TVOCs are technically different, the terms are often used interchangeably.


How do VOCs get into an indoor air environment?  Many times they are emitted from items that are in indoor spaces in either solid or liquid form.  Paints and varnishes, building materials, furniture and carpeting, household cleaners, cigarette smoke, and even personal care products emit VOCs.  The complete list of VOC-emitting products and materials would have hundreds more items on it. 


VOCs can also get indoors by way of contaminated soil or groundwater under a building.  If VOCs are present in these media they can migrate into a building through cracks in the foundation, basement floor, sewer lines, or any penetration that compromises the barrier between the building and the surrounding soil.  This phenomenon is called vapor intrusion. 


There are thousands of VOCs.  They can be naturally-occurring or synthetic.  Some are highly toxic, others are moderately toxic, and still others are mildly toxic.  Each VOC or class of VOCs has its own set of potential negative health effects.  Many of the common VOCs have been well studied.  In these cases their toxic properties are understood and exposure limits or guidelines have often been established.  Formaldehyde, perchloroethylene, benzene, and xylene fall in this group.  Unfortunately, many VOCs have yet to be evaluated for their potential to harm workers or other building inhabitants. 


VOCs can negatively impact indoor air quality if they are present in concentrations that will cause building inhabitants to experience medical signs and symptoms or become sick.  Complaints of eye, skin, and throat irritation, headache, nausea, and fatigue are common in buildings with elevated levels of VOCs. 


Are indoor air VOCs harmful?  Here's where things get tricky, as it depends on the specific VOC in question, the concentration of that VOC, and the toxic properties of that VOC.  If you know the specific VOC involved and if that VOC has an exposure limit, air monitoring can be performed and the results can then be compared to the corresponding exposure limit.  Concentrations above the exposure limit will increase the risk of adverse health effects.   


If you suspect that VOCs are impacting your indoor air quality but don't know which VOCs are responsible you can obtain a representative grab sample of the air and request a VOC analysis to identify the culprits.  Like the scenario described above, the VOC concentrations can then be compared to the exposure limits.


Sometimes it's difficult to identify the offending VOCs - or they are identified but don't have exposure limits.  In these situations you can use a real-time monitor to screen the space for TVOCs.  If VOCs are present, an overall concentration will be reported.  While there are no exposure limits for TVOCs some guidelines have been recommended.  Generally, TVOC concentrations between 50 parts per billion (ppb) and 325 ppb are thought to be acceptable.  Similarly, it's often recommended that indoor air TVOC concentrations not exceed 500 ppb.  More in-depth evaluations and investigations should be performed if TVOC concentrations exceed this value.


It makes good sense to keep all indoor air VOC concentrations as low as reasonably achievable.   Thorough investigations which focus on identifying the source of VOCs and reducing VOC concentrations are crucial.  Certified Industrial Hygienists have the training to perform these investigations and navigate through the uncertainties of unknown VOCs and the lack of exposure limits.  They can assess the building in order to identify which items are contributing to the indoor air VOC load.  Likewise, they can recommend measures which will eliminate, reduce, or control VOC concentrations and reduce the risk of adverse health effects. 


Do you have indoor air quality concerns?  Do you suspect VOCs or other agents are to blame?                                                                                        

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