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What are the dangers of indoor air pollution

Čas: 2020 08--20

Indoor air pollution refers to chemical, biological and physical contamination of indoor air. It may result in adverse health effects.

In developing countries, the main source of indoor air pollution is biomass smoke which contains suspended particulate matter (5PM), nitrogen dioxide (NO2), Sulphur dioxide (SO2), carbon monoxide (Ca), formaldehyde and polycyclic aromatic hydrocarbons (PAHs).

In industrialized countries, in addition to NO2, CO, and formaldehyde, radon, asbestos, mercury, human-made mineral fibers, volatile organic compounds, allergens, tobacco smoke, bacteria and viruses are the main contributors to indoor air pollution.

What are the harmful substances in the air?

The EPA requires businesses to report on how much of the following chemicals are being released into the air.

(1) Carbon Monoxide

Carbon monoxide is a very toxic pollutant that forms when there is a lack of oxygen to make carbon dioxide. Carbon monoxide can cause a lack of oxygen in one's body, which can become life-threatening very quickly.

For overall health and safety of the public, the EPA has set the following carbon monoxide standards: 9 parts per million for eight hours and 35 parts per million for one hour.

(2) Ozone

The ozone is made up of a toxic blue gas and it has a very distinct (and unpleasant) odor. This gas is made up of three oxygen atoms. Breathing in this gas can cause the public severe respiratory distress, and even death. Bad ozone levels can even cause distress to our planet's vegetation.

(3) Lead

This metal is found in our environment organically, and it is also found in man-made items. The most well-known source of emissions of lead comes from fuel. Fuel from our vehicles produce the most lead in our air. Also, fuel from air crafts emit exponential amounts of fuel into the air.

(4) Nitrogen dioxide

This is a highly reactive gas that is emitted from vehicles and power plants. It is a known contributor to bad, ground-level ozone levels.

In January 2010, the EPA issued a standard for nitrogen dioxide at 100 parts per billion, over a one hour span.

If this gas reaches dangerous levels, it can cause the public severe respiratory distress.

(5) Particulate matter

This mixture of small particles and liquid droplets have a number of components to it. These components include dust, acids, soil, organic chemicals and metals.

Particles that are 10 micrometers or smaller are able to be breathed in by humans and animals which, in turn, can cause severe distress.

(6) Sulfur dioxide

This highly reactive gas is emitted from fossil fuels (via power plants) and industries. This gas is released when metal is being extracted from ore.

The EPA issued an air quality standard of 75 parts per billion over a span of one hour.

What are the Possible Sources of Indoor Air Pollution?

Indoor pollution sources that release gases or particles into the air are the primary cause of indoor air quality problems.

Inadequate ventilation can increase indoor pollutant levels by not bringing in enough outdoor air to dilute emissions from indoor sources and by not carrying indoor air pollutants out of the area.

High temperature and humidity levels can also increase concentrations of some pollutants.

There are many sources of indoor air pollution. These can include:

Fuel-buring combustion appliances

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Building materials and furnishings as diverse as:

Deteriorated asbestos-containing insulation

Newly installed flooring, upholstery or carpet

Cabinetry or furniture made of certain pressed wood products

Products for household cleaning and maintenance, personal care, or hobbies

Central heating and cooling systems and humidification devices

Excess moisture

Outdoor sources such as:



Outdoor air pollution.

The relative importance of any single source depends on how much of a given pollutant it emits and how hazardous those emissions are.

In some cases, factors such as how old the source is and whether it is properly maintained are significant. For example, an improperly adjusted gas stove can emit significantly more carbon monoxide than one that is properly adjusted.

Some sources, such as building materials, furnishings and products like air fresheners, can release pollutants more or less continuously.

Other sources, related to activities like smoking, cleaning, redecorating or doing hobbles release pollutants intermittently. Unvented or malfunctioning appliances or improperly used products can release higher and sometimes dangerous levels of pollutants indoors.

Pollutant concentrations can remain in the air for long periods after some activities.

Learn more about indoor air pollutants and sources of:


Biological Pollutants

Carbon Monoxide (CO)

Formaldehyde/Pressed Wood Products

Olovo (Pb)

Nitrogen Dioxide (NO2)


Radon (Rn)

Indoor Particulate Matter

Secondhand Smoke/ Environmental Tobacco Smoke

Stoves and Heaters

Fireplaces and Chimneys

Těkavé organické sloučeniny (VOC)

How does indoor air quality affect our 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.

Dlouhodobé účinky

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.

WHO Guidelines for indoor air quality

In 2014, WHO issued the first-ever health-based guidelines on clean fuels and technologies for household cooking, heating and lighting. These guidelines aim to help public health policy-makers, as well as specialists working on energy and resource issues, understand and implement best approaches to reducing household air pollution. This extensive scientific assessment identifies which energy systems can be considered clean for health in the home, and specifies the levels of emissions that pose health risks.

The guidelines also include recommendations against the use of unprocessed coal as a household fuel, and against the use of kerosene as a household fuel, in the light of health and safety risks. Another recommendation addresses the need for policies that prioritize substantial health benefits during the transition from use of solid, polluting fuels to clean fuels and technologies, especially in low-income and rural households.

These guidelines make recommendations for reducing health risks from exposure to ambient emissions of gases and chemicals that may infiltrate and collect indoors, as well as from chemicals that may be used in building materials or furnishings that contribute to indoor air pollution. Pollutants covered include benzene, carbon monoxide, formaldehyde, naphthalene, nitrogen dioxide, polycyclic aromatic hydrocarbons, radon, trichloroethylene and tetrachloroethylene. These substances are often found indoors in concentrations high enough to merit concern.

The guidelines aim to eliminate or reduce exposure to these pollutants, and are targeted at public health professionals, specialists and authorities involved in the design of buildings and indoor materials and products. They provide a scientific basis for legally enforceable standards. The WHO is working on producing an updated set of guidelines on selected pollutants.

These guidelines review the evidence on health impacts from indoor dampness and exposure to microbes such as mould, fungi and bacteria which emit spores into indoor air. The document also summarizes the available information on the conditions that determine the presence of mould and measures to control their growth indoors. The review concludes that the most important health effects are increased prevalence of respiratory symptoms, allergies and asthma as well as perturbation of the immunological system.

WHO guidelines for protecting public health are formulated on the basis of the review. Dampness initiates the chemical or biological degradation of materials, which also pollutes indoor air. The guidelines also explain how well-designed, well-constructed, well-maintained building envelopes are critical to the prevention of microbial growth and moisture. The most important means for avoiding adverse health effects is the prevention (or minimization) of persistent dampness and microbial growth on interior surfaces and in building structures.

he WHO air quality guidelines offer guidance on reducing the effects on health of air pollution. This article presents revised guideline values for the four most common air pollutants - particulate matter, ozone, nitrogen dioxide and sulfur dioxide - based on a review of the accumulated scientific evidence.

The rationale for selection of each guideline value is supported by a synthesis of information emerging from research on the health effects of each pollutant. As a result, these guidelines now also apply globally. They can be read in conjunction with Air quality guidelines for Europe, 2nd edition, which is still the authority on guideline values for all other air pollutants