Indoor air quality

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Ionic concentrations in the outside air

The term indoor air quality or indoor air quality (Engl. Indoor Air Quality ) called those aspects of are air considered the impact on the well-being and health are of men. In industrial production plants (see clean room ), in the storage of goods or in animal husbandry, there may be requirements for indoor air quality. People in Europe spend an average of 90% of their life indoors today . Each person breathes in 10 to 20 m 3 of air per day, depending on age and activity , which corresponds to a mass of 12 to 24 kg of air. This is far more than what a person ingests through food (food and drinking water). Against this background, it becomes clear how important the quality of indoor air is for people's wellbeing.

background

Non-smoker protection in Japan: Enclosed smoking room in a train station - air extraction on the roof.

Since people spend a large part of their private and professional lives in rooms or means of transport (on average more than 90% in industrialized countries ), the quality (purity) of the indoor air is more important to health than the outside air, which is usually better monitored. This deficiency is partially countered by the European standard EN 13779 , which came into force on October 1, 2009, as it prescribes a certain air quality at least for non-residential buildings . It has now been replaced by EN 16798-3.

Many different criteria can be used to assess the air quality inside buildings, some of which can be recorded using suitable measurement methods and others only through a direct assessment of the users (people).

The European standard 15251 defines the framework parameters for the indoor climate that have an impact on the overall energy efficiency of buildings. These must be observed for the design of buildings and air conditioning systems. The design internal temperature is used as a target value for the calculation of the heating load (EN 12831) and the cooling load (EN 15243) depending on the temperature of the outside air (winter and summer). The input values ​​are used to measure the technical equipment of buildings.

Expectations of the room users

Ion concentrations in the air indoors and outdoors

The user of a room has two essential requirements for the room air:

  1. There are no harmful substances in the air in dangerous concentrations.
  2. The air is not perceived as musty , foul smelling or stale.

Since the second criterion in particular depends very much on the personal feelings of the individual person, good indoor air quality corresponds to a large number of satisfied room users, provided there are no pollutants in the room air.

According to their definition, indoor air quality cannot be measured, but can only be perceived subjectively by the users of a room.

Normative categories of indoor climate and indoor air quality

The level of expectations of the user regarding the quality of the indoor climate is divided into four categories by EN 15251. The quality of the indoor air is an input parameter for assessing the indoor climate.

  • Category I: high level of expectations (rooms for sensitive and sick people, e.g. children, the elderly, the sick, ...)
  • Category II: normal level of expectations (rooms in new and renovated buildings)
  • Category III: moderate level of expectations (rooms in existing buildings)
  • Category IV: values ​​outside of cat. I to III, no expectations (limited part of the year)

For new and refurbished existing buildings, category II is recommended as the basis for planning and designing the ventilation technology . Deviating classifications must be agreed with the client. Categories I to III of DIN EN 15251 can also be transferred to categories A to C of DIN EN ISO 7730.

EN 13779 , which was withdrawn in November 2017, defined the quality of indoor air, referred to as Indoor Air (IDA), in four categories:

  • Category IDA 1: high indoor air quality
  • Category IDA-2: Medium indoor air quality
  • Category IDA-3: Moderate indoor air quality
  • Category IDA-4: Low indoor air quality

The EN 16798-3, which has been in force since November 2017, defines the supply air quality instead. The indoor air quality depends on the type and effect of the pollution considered and whether there are e.g. B. mainly adults, children or the sick.

Influential factors on the indoor climate

Loads of indoor air

The indoor air can be polluted with pollutants from a variety of sources, e.g. B.

and many others.

Thermal indoor climate

Examples of typical comfort
limits above operative temperature
room category Minimum
heating period
Maximum value
cooling period
Residential buildings 1 21 ° C 25.5 ° C
2 20 ° C 26 ° C
3 18 ° C 27 ° C
Office, conference room,
lecture hall
1 21 ° C 25.5 ° C
2 20 ° C 26 ° C
3 19 ° C 27 ° C
kindergarten 1 19 ° C 24.5 ° C
2 17.5 ° C 25.5 ° C
3 16.5 ° C 26 ° C

A comfortable room temperature for humans depends on the person's heat emission. The perceived room temperature is called the operative temperature and is the mean value of the air and radiation temperature. For this purpose, guideline values ​​for the comfort limits are recommended for defined clothing, activity, air speed and air humidity for a wide variety of rooms. Categories 1–4 can be used to predict the percentage of people who are satisfied: over 94%, over 90%, over 85% and up to 85%.

humidity

Humidity that is beneficial for humans is above 15… 20 % RH as long as the water content does not exceed 12  g / kg . Below 15… 20% RH, dryness and thus irritation of the eyes and airways can occur in humans. The clothed person feels humid above a water content of 12 g / kg. At temperatures above 0 ° C, humidity levels above 80 % rh promote microbial growth.

Building physics requirements against condensation in the masonry (mold formation), requirements of certain buildings such as museums, historical buildings, churches or requirements of production processes (paper industry) may require different air humidity.

Air speed

The air speed in the occupied area is limited as a draft risk (percentage of people who are dissatisfied with it) or as the maximum mean air speed. Depending on the operational room temperature and the degree of turbulence, the air speeds are usually between 0.1 and 0.2 m / s. Above an operative temperature of 25 ° C, higher air speeds of up to 0.9 m / s are perceived as pleasant. So it is, for. B. when using a manual table or ceiling fan, the real operative room temperature of 28 ° C perceived as a more pleasant 25.3 ° C.

Evaluation concepts for indoor air quality

Four different assessment concepts are used in Germany to assess chemical contamination of indoor air.

In practice, the qualitative determination takes place according to four methods, which are used depending on the nature of the room; namely according to:

  1. Outside air flow per person (room in which predominantly people stay, e.g. office) The satisfaction rate in categories 1–4 is over 85%, 80%, 70% and up to 70%.
  2. Air volume flow per floor area (no common area for people, e.g. storage room)
  3. CO 2 concentration (room in which predominantly natural vapors from people predominate)
  4. Concentration of certain impurities (room with significant emission)
Evaluation concepts for indoor air according to Sagunski, Heinzow and Müller
Evaluation concept Definition / explanation Remarks
Reference value Statistical status description; Mapping of the interior situation only at a certain time period for a defined interior space under defined measurement conditions Health not justified; not legally binding
Conductance Health and hygienic justified assessment value of a substance for which the state of knowledge is insufficient to derive a toxicologically justified guide value (guideline VDI 6022 Part 3) Not legally binding
Guideline Toxicologically derived value based on suitable knowledge of toxic effects and dose-effect relationships of the respective substance (guideline VDI 6022 Part 3) Not legally binding, but can acquire legal significance
limit Statutory assessment value which must be adhered to and which must be sufficiently safely undershot (guideline VDI 6022 Part 3) Legally binding; Legislative limit values ​​(result of a parliamentary process) and administrative limit values ​​(bind administration and affected groups, e.g. building owners)

Guide values ​​for indoor air quality

While limit and guideline values ​​according to the Technical Rules for Hazardous Substances (TRGS) apply to workplaces where hazardous substances are handled, this does not apply to rooms. The maximum workplace concentration (MAK) known from occupational safety is not used to assess the room air.

An ad-hoc working group (representatives of the Indoor Air Hygiene Commission (IRK) of the Federal Environment Agency and the Working Group of the Supreme Health Authorities of the Federal States (AOLG)) was set up in December 1993 to develop guide values ​​for indoor air quality in Germany . On the basis of a basic scheme published in 1996, indoor air guide values ​​are drawn up for individual substances, whereby two guide values ​​are specified:

Guide value II (RW II) is an effect-related, justified value, which is based on the current toxicological and epidemiological knowledge of the effect threshold of a substance with the introduction of uncertainty factors. It is the concentration of a substance that requires immediate action when it is reached or exceeded, as this concentration is particularly suitable for endangering the health of sensitive people who stay in the rooms for a long time. The reference value II of a substance can be defined as a short-term value (RW II K) or long-term value (RW II L).

Guide value I (RW I) is the concentration of a substance in the room air at which, according to the current state of knowledge, no health impairments are to be expected in the context of an individual substance consideration, even with lifelong exposure . Exceeding this is associated with a hygienically undesirable burden that goes beyond the usual level. For precautionary reasons, there is also a need for action in the concentration area between RW I and RW II. RW I is derived from RW II by introducing an additional factor (usually 10). This factor is a convention. RW I can serve as a renovation target value. It should not be exhausted, but rather undercut if possible.

Austria has published a slightly different assessment concept for interiors. There is only one guideline value per pollutant, the WIR (impact-related indoor area guideline value), which is determined by the indoor air working group at the Ministry of the Environment together with the Academy of Sciences .

Examples of guide values ​​for inorganic and organic compounds in indoor air in Germany (source: Federal Environment Agency Berlin)
connection Inorganic Organic Guide value II
in µg / m³
Guide value I
in µg / m³
Year of establishment
Carbon monoxide X   60000 (1/2 h) 6000 (1/2 h) 1997
Nitrogen dioxide, NO 2 X   350 (1/2 h) - 1997
mercury X   0.35 0.035 2008
toluene   X 3000 300 1996
Pentachlorophenol   X 1 0.1 1997
naphthalene   X 30th 10 2013

Analytics

Since the substances in the room air are usually only present in very low concentrations, they must first be enriched before detection. In the past, a defined volume of air was pumped through a gas washing bottle with an absorber liquid. Today the substances are adsorbed in a collector . A distinction is made between an active and a passive collector . With the passive collector, the adsorption material is placed in the room, whereby the substances accumulate over a longer period of time through diffusion . With the active collector, a defined volume of air (several m³) is pumped through the adsorption medium. Before the actual detection, the adsorption material is heated in order to release the collected substances again.

The detection of the substances is always carried out using the methods of environmental analysis , essentially the spectroscopic method and gas chromatography with mass spectrometry coupling . The flame ionization detector (FID) is also used to determine the total number of hydrocarbons .

The room air can also be monitored with gas sensors or air quality sensors . This applies in particular to workplaces and living areas with ventilation technology for controlled ventilation.

For the evaluation of materials regarding possible issues that will test chamber used. Test chambers are used in particular to evaluate building materials and equipment parts for vehicle interiors. The first test chambers were developed in the mid-1970s to determine the formaldehyde emission from wood-based materials. The measurement methods are described in international standards; for building materials in DIN EN 16516, for vehicle interior trim parts in the DIN ISO 12219 series of standards.

Indoor air quality research

Since the 1970s, a number of disorders have been observed that cannot be traced back to a specific illness, but are associated with being indoors and subside as soon as the building is left.

The non-profit Catalysis Institute for Applied Environmental Research , founded in 1978, has a work and research area "Indoor Air Research and Electrosmog ".

The research area is also referred to as " ventilation and air conditioning ". Since more modern houses have a denser building envelope than they used to be (see passive house ), central ventilation systems are increasingly being built into residential buildings. These usually have a heat exchanger for the purpose of " heat recovery " , which extracts part of the energy from the air blown out and transfers this to the air drawn in. The outside air can be cleaned of fine dust , pollen and much more with an air filter . (More details in the article " controlled living space ventilation ").

Since 1983, a number of disorders related to the quality of the indoor air, among other things, have been grouped under the so-called " Sick Building Syndrome " (SBS). The World Health Organization (WHO) summarized these disorders under the term “Sick Building Syndrome” (SBS) and coined the term SBS (WHO) for the first time.

The Federal Government has also been dealing with indoor air quality and the problems that arise in various working groups for many years. Many specialist circles and federal offices are looking for ways and solutions to deal holistically with the issue and problem of indoor air quality.

See also

Web links

Wiktionary: Indoor air quality  - explanations of meanings, word origins, synonyms, translations

Individual evidence

  1. ^ Federal Environment Agency Germany
  2. ionized air in the interior (PDF; 890 kB), University of Lucerne Research & Architecture, issue 01/2013 , accessed on January 21, 2020
  3. Hartmut Finger, Ute Schneiderwind, Christof Asbach: Evaluation of mobile room air purification devices. In: Hazardous substances - cleanliness. Air . 75, No. 11/12, 2015, ISSN  0949-8036 , pp. 497-502.
  4. DIN EN 15251 . Input parameters for the indoor climate for the design and evaluation of the energy efficiency of buildings - indoor air quality, temperature, light and acoustics. Beuth Verlag, December 2012, p. 5 .
  5. DIN EN 15251 . Input parameters for the indoor climate for the design and evaluation of the energy efficiency of buildings - indoor air quality, temperature, light and acoustics - National Annex. Beuth Verlag, December 2012, p. 12 .
  6. DIN EN 15251 NA . Input parameters for the indoor climate for the design and evaluation of the energy efficiency of buildings - indoor air quality, temperature, light and acoustics. Beuth Verlag, December 2012, p. 7 .
  7. DIN EN 13779 . Ventilation of non-residential buildings - General principles and requirements for ventilation, air conditioning and room cooling systems. Beuth Verlag, September 2007, p. 19 (Was withdrawn with the publication of DIN EN 16798-3 in November 2017.).
  8. DIN EN 16798-3 . Energetic assessment of buildings - Ventilation of buildings - Part 3: Ventilation of non-residential buildings - Performance requirements for ventilation and air conditioning systems and space cooling systems. Beuth Verlag, November 2017, p. 2 (replaces EN 13779.).
  9. a b Report Indoor Workplaces, Chapter 12, "Chemical Effects. (PDF) German Statutory Accident Insurance eV, accessed on May 24, 2018 .
  10. Jenny Schäfer, Christoph Trautmann, Ingrid Dill, Guido Fischer, Thomas Gabrio, Ingrid Groth, Udo Jäckel, Wolfgang Lorenz, Karin Martin, Tinja Miljanic, Regine Szewzyk, Ursula Weidner, Peter Kämpfer: Occurrence of actinomycetes in interiors. Hazardous substances - keeping the air clean 69 (9), 2009, pp. 335–341, ISSN  0949-8036
  11. a b Helmut Sagunski, Birger Heinzow, Ludwig Müller: Reference values, conductance, guide values ​​and limit values ​​for indoor air . A quick guide. Hazardous substances - keeping the air clean 73 (4), 2013, pp. 169–175, ISSN  0949-8036
  12. Source for toluene see Innenraumanalytik.at (PDF; 210 kB)
  13. Fiedler 2012, Bischof & Wiesmüller 2007, Lindvall 1992, Norbäck 1992, Sullivan Jr. et al. 1992
  14. katalyse.de ( Memento of the original from March 16, 2010 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. KATALYSE Institute for Applied Environmental Research e. V. accessed on July 15, 2013 @1@ 2Template: Webachiv / IABot / www.katalyse.de
  15. Sick Building Syndrome Federal Environment Agency , accessed on January 21, 2020
  16. Indoor air , Federal Environment Agency , accessed on January 21, 2020
  17. Health and Environmental Hygiene - Indoor Air Hygiene Commission (IRK) Federal Environment Agency , PR November 10, 2010, accessed on June 7, 2013