Indoor Air Measurements

Indoor air measurements

Having our own air sampling instruments readily at hand, we may arrange measurements very flexibly. The measurements are carried out according to the appropriate norms and standards.

The results and their interpretation are summarised in an illustrated report, including correlation to limit values, and if necessary recommendations for operational or constructional measures to be taken.

Asbestos

Asbestos indoor air measurements are performed in accordance with VDI Guideline 3492 “Measurement of inorganic fibrous particles”, using air samplers equipped with a single-use monitor with core depth filter steamed with gold. In Switzerland the limit values for Asbestos in the workplace are set at 0.01 respirable Asbestos fibres per ml of air (= 10'000 respirable Asbestos fibres per m³ of air). After an Asbestos clean-up, concentrations above 1’000 respirable Asbestos fibres (RAF) per cubic meter (m³) of air are not tolerated. With regard to residential buildings, however, there are no legal limit values for Asbestos in indoor air. The Swiss Federal Office of Public Health recommends keeping Asbestos contamination as low as possible, if possible below detection limit (< 100 RAF per m³). Where friable Asbestos applications have been removed, or bonded Asbestos products have been broken, cut, damaged or disturbed, indoor air measurements must be carried out before using the rooms again. Only such measurements will allow an assessment of the effectiveness of the remedial works and measures.

Polychlorinated Biphenyls (PCBs)

PCB indoor air measurements are performed by air samplers equipped with polyurethane foam, according to the procedures stipulated in VDI Guideline 4300, Part 2 “Measurement of indoor air pollution”. If indoor air measurements reveal an average concentration of > 6‘000 ng/m³ resp. > 2‘000 ng PCB per m³ indoor air (areas with eight hours stay per day resp. permanent stay), remedial measures must be taken according to the PCB Guideline published by the Swiss Federal Office for the Environment in 2003. There is no national limit value for the acceptable maximum indoor air contamination after a PCB remediation. Most Swiss cantons, however, refer to the PCB Guideline of the German Federal State North Rhine-Westphalia, wherein a value of 300 ng/m³ PCB is stipulated. These cantons allow a tolerance of ± 100 %. Consequently, the maximum value of PCB in indoor air after a PCB remediation is ≤ 600 ng/m³.

Chlorinated Paraffins (CPs)

CP indoor air measurements are performed by air samplers (collection medium polyurethane foam). The sampling is based on VDI Guideline 4301, Part 5, and DIN ISO 16000-12 & 13. The German Bundesanstalt für Arbeitsschutz und Arbeitsmedizin has set the limit value for MCCPs in the workplace at 6 mg/m³, which is also applicable for SCCPs. At present there are no binding values in Switzerland.

Polycyclic Aromatic Hydrocarbons (PAHs)

PAH indoor air measurements are performed by air samplers (collection medium polyurethane foam). The sampling is based on VDI Guideline 4301, Part 5, and DIN ISO 16000-12 & 13. In case of PAH indoor air measurements, carcinogenic Benzo[a]pyrene is usually considered the lead substance. The Swiss limit value for B[a]P in the workplace is 0,002 mg/m³. The German Umweltbundesamt (UBA) provides guidance values for Naphthalene and Naphthalene-like compounds: Precautionary value: 0.01 mg/m³; intervention value: 0.03 mg/m³.

Volatile Organic Compounds (VOC)

VOC indoor air measurements are performed by air samplers (collection medium Tenax®), according to VDI Guideline 3482 and DIN ISO 16000-6. Due to the lack of Swiss guidelines on indoor air contamination limit values, our interpretation of results as well as risk assessments are often based on German values and recommendations. The German Umweltbundesamt (UBA) has defined precautionary and intervention values for some VOC.

Flame retardants and wood preservers

Indoor air measurements for flame retardants or wood preservers are performed by air samplers (collection medium polyurethane foam). The sampling is based on VDI Guideline 4301, Part 5, and DIN ISO 16000-31. Due to the lack of Swiss guidelines on indoor air contamination, our interpretation of results as well as risk assessment are usually based on German values and recommendations. Guidance values in Germany for some flame retardants on the basis of phosphoric acid:

• TCEP: Precautionary value: 0,005 mg/m³; intervention value: 0,05 mg/m³
• Pentachlorophenol (PCP): Precautionary value for rooms with permanent stay > 8 hours/day: 0,1µg/m³ ; precautionary value for other rooms (< 8 hours/day): 1 µg/m³
• Mono- and Dichloronaphtalenes: Precautionary value: 0,002 mg/m³; intervention value: 0,02 mg/m³

Radon

In areas where radon is known to occur, we monitor the indoor air with our Alpha Guard measurement equipment for 3 to 5 days. For the annual average radon gas concentration in rooms where people are frequently present for several hours per day, a radon reference level of 300 Becquerel per cubic meter (Bq/m³) applies (see Swiss Radiological Protection Ordinance ).