Information provided from USEPA booklet, Indoor Air Pollution.
Indoor air pollution poses many challenges to the health professional.  This booklet offers an overview of those challenges, focusing on acute conditions, with patterns that point to particular agents and suggestions for appropriate remedial action.
The individual presenting with environmentally associated symptoms is apt to have been exposed to airborne substances originating not outdoors, but indoors. Studies from the United States and Europe show that persons in industrialized nations spend more than 90 percent of their time indoors.1 For infants, the elderly, persons with chronic disease, and most urban residents of any age, the proportion is probably higher. In addition, the concentrations of many pollutants indoors exceed those outdoors. The locations of highest concern are those involving prolonged, continuing exposure -- that is, the home, school, and workplace.
The lung is the most common site of injury by airborne pollutants. Acute effects, however, may also include non-respiratory signs and symptoms, which may depend upon toxicological characteristics of the substances and host-related factors.
Heavy industry-related occupational hazards are generally regulated and likely to be dealt with by an on-site or company physician or other health personnel.2  This booklet addresses the indoor air pollution problems that may be caused by contaminants encountered in the daily lives of persons in their homes and offices. These are the problems more likely to be encountered by the primary health care provider.
Etiology can be difficult to establish because many signs and symptoms are nonspecific, making differential diagnosis a distinct challenge. Indeed, multiple pollutants may be involved. The challenge is further compounded by the similar manifestations of many of the pollutants and by the similarity of those effects, in turn, to those that may be associated with allergies, influenza, and the common cold. Many effects may also be associated, independently or in combination with, stress, work pressures, and seasonal discomforts.
Because a few prominent aspects of indoor air pollution, notably environmental tobacco smoke and "sick building syndrome," have been brought to public attention, individuals may volunteer suggestions of a connection between respiratory or other symptoms and conditions in the home or, especially, the workplace. Such suggestions should be seriously considered and pursued, with the caution that such attention could also lead to inaccurate attribution of effects. Questions listed in the diagnostic leads sections will help determine the cause of the health problem. The probability of an etiological association increases if the individual can convincingly relate the disappearance or lessening of symptoms to being away from the home or workplace.
How to Use This Booklet
The health professional should use this booklet as a tool in diagnosing an individual's signs and symptoms that could be related to an indoor air pollution problem. The document is organized according to pollutant or pollutant group. Key signs and symptoms from exposure to the pollutant(s) are listed, with diagnostic leads to help determine the cause of the health problem. A quick reference summary of this information is included in this booklet. Remedial action is suggested, with comment providing more detailed information in each section. References for information included in each section are listed at the end of that section.
It must be noted that some of the signs and symptoms noted in the text may occur only in association with significant exposures, and that effects of lower exposures may be milder and more vague, unfortunately underscoring the diagnostic challenge. Further, signs and symptoms in infants and children may be atypical (some such departures have been specifically noted).
The reader is cautioned that this is not an all-inclusive reference, but a necessarily selective survey intended to suggest the scope of the problem. A detailed medical history is essential, and the diagnostic checklist may be helpful in this regard. Resolving the problem may sometimes require a multidisciplinary approach, enlisting the advice and assistance of others outside the medical profession. The references cited in the notes throughout and in the For Assistance and Additional Information section will provide the reader with additional information.
References
1  U.S. Environmental Protection Agency, Office of Air and Radiation. Report to Congress on Indoor Air Quality, Volume II: Assessment and Control of Indoor Air Pollution, pp. i, 4-14. EPA-400-1-89-001C, 1989.
2  The U.S. Environmental Protection Agency sets and enforces air quality standards only for ambient air. The Toxic Substances Control Act (TSCA) grants EPA broad authority to control chemical substances and mixtures that present an unreasonable risk of injury to health and environment. The Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) authorizes EPA to control pesticide exposures by requiring that any pesticide be registered with EPA before it may be sold, distributed, or used in this country. The Safe Drinking Water Act authorizes EPA to set and enforce standards for contaminants in public water systems. EPA has set several standards for volatile organic compounds that can enter the air through volatilization from water used in a residence or other building. As to the indoor air in workplaces, two Federal agencies have defined roles concerning exposure to (usually single) substances. The National Institute for Occupational Safety and Health and Human Services (NIOSH), part of the Department of Health and Human Services, reviews scientific information, suggests exposure limitations, and recommends measures to protect workers' health. The Occupational Safety and Health Administration (OSHA), part of the Department of Labor, sets and enforces workplace standards. The U.S. Consumer Product Safety Commission (CPSC) regulates consumer products which may release indoor air pollutants. In the United States there are no Federal Standards that have been developed specifically for indoor air contaminants in non-occupational environments. There are, however, some source emission standards that specify maximum rates at which contaminants can be released from a source.
For more extensive information, see the publication cited above, in particular Chapter 7, "Existing Indoor Air Quality Standards," and Chapter 9, "Indoor Air Pollution Control Programs.