Category Archives: indoor airpollution

indoor airpollution

Building biologist first looks at the floor structure

Floor identified as source of pollutants

Floor identified as source of pollutants

How to find pollutants in the house

When looking for the source of pollutants in the indoor air, Oliver Zenkel always focuses on the floor first. The building biologist draws on several years of experience and also provides a simple reason. Although walls have the larger surface portion at a dwelling, but floors are usually multi-layered developed and thus substantially more susceptible for pollutant entries into the ambient air. Zenkel views flooring as a system in which not only the individual material plays a role, but also the interaction of the components.
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Residential toxins in old prefabricated house

prefabricated house real estate check

prefabricated house real estate check

Building biologists are regularly asked for advice

Prefabricated houses from the seventies are part of the fixed portfolio of real estate agents. Mostly, the offers are tempting for young families. The most important plus points are considered to be a prime location, a relatively large plot of land, a good room layout and, ultimately, a favorable price. Too often, homebuyers suppress the problem of pollutants in older prefabricated houses. Even fifty years after completion, certain groups of pollutants have not yet been aired out.
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Using the ACI value to assess the radioactivity of building materials

gamma rays in building materials

Gamma rays in building materials endanger health

The European Union (EU) has developed the Activity Concentration Index to assess radiation exposure

The large-scale installation of radioactive building materials indoors can endanger the health of the occupants. Granite, tuff or pumice are building materials with radioactive potential. However, sand, gravel, limestone and natural gypsum can also be radioactively contaminated under certain circumstances. The builder does not always know which rock is in a product. For example, a masonry block is offered under the brand name “Liapor”, without the buyer knowing that pumice rock is hidden behind it. The European Union has therefore developed the Activity Concentration Index (ACI) to assess radiation exposure from building materials indoors. The Institute for Building Biology in Rosenheim (Germany) recommends an ACI value of less than 0.75 for health protection.
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Boundary conditions for mobile room air cleaners

Air cleaner Dustcontrol

Air cleaner Dustcontrol


Mobile air purifiers are booming in times of pandemics. Manufacturers of these devices outbid each other with superlatives. The German statutory accident insurance (DGUV) sees the use of the air recirculation units in a much more differentiated way. For example, the accident insurer points out important boundary conditions that must be observed when using the devices in classrooms.
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Strong smell after sanding the floor

strong odor form cresols

Renovating a house from the 1960s

A young family in Thuringia (Germany), full of enthusiasm, renovated a house from the 1960s. They wanted to keep the floorboards on the first floor and started sanding off the top layer. But after a short time the Stickler family was very sober. During the work it started to stink terribly. Ms. Stickler also worried about her child’s health. A building biologist should investigate the process to find the reason for the unpleasant smell. The expert sampled the room air using the TENAX method (2 liters of air at a volume flow of 100 milliliters per minute). As a precaution, he took a material sample from the flooring.
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Tar cardboard containing PAH caused odor problems and headaches

naphtalene found in the air of two classrooms

Naphtalene found in the air of two classrooms

Measurement results showed a pollution with naphthalene

In a primary school in Saxony (Germany), odor problems had arisen in two classrooms and in the staff room since the building was renovated. When a new rector took office in 2018, the matter really got going. Ms. Rubens (name changed) not only had a sensitive nose, but increasingly complained of a headache as soon as she was in the staff room. The school administration informed the city administration as the responsible cost bearer. The local building authority then commissioned an engineering office to investigate the indoor air. The measurement results showed a clear pollution of the room air with naphthalene. Since even the guideline II of the German Federal Environment Agency was exceeded with 20 µg / m³, no lessons were allowed to take place in the rooms from now on. A review of the construction plans showed that the school was built in 1964. Therefore, the experts consulted assumed that the building was contaminated. The energetic renovation in 2017 had obviously exacerbated the smell problem. The airtight facade and the lack of controlled ventilation ensured that the pollutants in the indoor air could accumulate more.
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Too many pollutants in the carpets

Carpets may contain toxins

Carpets may contain toxins

People love their carpets – 1.8 million tonnes are sold in Europe year after year. This is also the second largest carpet market next to the USA. The market leader today is Tarkett in France, followed by the Balta Group from Belgium. The production of a carpet takes place in several production steps. Each of the work stages uses a wide range of chemicals. The toxins contained therein later exhale into the room air or they are inhaled by the inhabitants as dust particles. Toxic chemicals are also the main obstacle to environmentally sound disposal. That’s why 1.6 million tons land in the waste incineration plant every year.
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PCB still causes concern

school building in GermanyIn mid-June 2018 press and television in Germany reported a request from the Left Party regarding a redevelopment concept for public buildings in the Saarland (Germany). The state government admitted that not all of these buildings had been systematically examined for PCB contamination. “The current building stock is not under general PCB suspicion,” says the state government and adds that there is no fundamental obligation for exploration PCB. “However, if refurbishment measures are planned for day care centers, precautionary measures will be carried out in the affected areas on the joints filled with PCBs”. Jochen Flackus, the parliamentary managing director of the Left Party, calls on the state government to develop a concept for the rehabilitation of PCB-contaminated buildings. Flackus points out that until around the 1980s, around 20,000 tons of PCB had been used as sealants in schools, kindergartens and other public buildings throughout Germany.
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Carbon monoxide detector as life insurance

carbon monoxid detector

Use high-quality devices to measure CO

The German Medical Journal reports 3,700 cases of poisoning with carbon monoxide (CO) per year, around ten percent of which end in death. Flue gases from poorly burning stoves or gas water heaters are still at the top of the polluter. But also in pellet storage rooms or shisha bars carbon monoxide accumulates in a dangerous concentration. When the urgently needed oxygen supply has to be done, a small electronic device can indicate. However, it is advisable to study the technical data carefully before buying CO detectors. Because the cheaper the device, the longer the response time. With high-quality devices, the response time is less than a minute; with low-cost solutions, it can take up to ten minutes before the warning is given. For users also to note: CO warning detectors must be additionally installed, because the “normal” smoke detector can not fulfill this function.
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Search for low-volatile organic compounds

wooden staircase

massive wooden staircase raises suspicion

Benjamin Kramer is looking at his dream house for the second time. A generously cut single-family house from the seventies, solidly built with brickwork and reinforced concrete ceilings. There is not much to complain about. Only the wood in the living and floor area worries him. A massive dark wooden staircase and several ceiling tiles are immediately visible. The attendant expert is feeling the discomfort. After the end of the tour, he therefore proposes that a precautionary analysis of house dust be initiated. Continue reading