PAB STANDARDS AND REGULATIONS
Many international and local regulations require the monitoring of indoor air quality in some public institutions like daycare or schools. In France for example, these regulations will extend this requirement to recreation centers and high schools on January 1st 2020 and to other institutions from January 1st 2023.
RELEVANT HAZARDOUS SUBSTANCES (POLLUTANT)
Three substances defined by the scientific community as priorities shall be measured and analyzed. These substances are formaldehyde, benzene and carbon dioxide. If the monitored building is located near a dry cleaner, tetrachloroethylene (perchloroethylene) should also be measured and analyzed.
Formaldehyde is an irritant substance to nose, eyes and breathing tracts exhausted by some construction materials, glues or cleaning products. This gas is toxic by inhalation (R23), in contact with skin (R24), if swallowed (R25) and may cause burns (R34). The IARC* unveiled a link between exposure to formaldehyde and risks of cancer (R40).
Benzene is a substance that can be found in fuels like unleaded gasoline and in exhaust gases. It has been classified as a category 1 carcinogenic agent R49) by the IARC* and may cause inheritable genetic damage (R46). In case of prolonged exposure, ingestion, inhalation or contact with skin, benzene has severe consequences on health (R48/23/24/25).
Carbon dioxide :
Carbon dioxide is a representative gas of containment level. Logic, reading and calculation excercices unveiled links between poor ventilation – which lead to high CO2 levels – and decline of children capabilities at school. This colorless and odorless gas features asphyxiating properties as it replaces oxygen in air.
Perchlorethylene is a very used solvent, particularly as a dry cleaning agent. It is also used as a degreasing agent, in textile treatment or in printing plants. The IARC* classified this substance as a category 2A potential carcinogenic agent (R40). It can cause an irritation to the eyes, dizziness and headache as well.
*IARC: International Agency for Research on Cancer (depends on WHO World Health Organization)
PUNCTUAL OR CONTINUOUS MONITORING
Formaldehyde and benzene punctual monitoring
I – Samples analysis shall be performed according to current good practice in compliance with local or international standards and regulations requirements.
II – Formaldehyde is analyzed through chemical desorption, followed by a high performance liquid chromatography added to an ultraviolet detector. The analysis process shall respect a quantification limit below 2 μg/m³ for a sampling period of 4.5 days.
III – Benzene is analyzed through thermal desorption, followed by a gaseous chromatography added to an ionization flame detection or mass spectrometry The analysis process shall respect a quantification limit below 0,4 μg/m³ for a sampling period of 4.5 days.
Carbon dioxide continuous monitoring
I – Continuous monitoring of carbon dioxide to asses air containment is performed with a non-dispersive infrared spectrometer with following technical specifications:
- Minimal measuring range: 0 to 5,000 ppm
- Incertitude à 20 °C et 1 013 mbar ± (50 ppm + 3 % de la valeur lue)
- Resolution: 1 ppm
- t63 response time: 200 seconds
- Measurement frequency: every 10 minutes
- Datalogging: 8 days minimum in 10 minutes increment.
II – Carbon dioxide measurement results are analyzed to calculate a containment indicator according the following method. A containment indicator is calculated from a continuous monitoring of carbon dioxide concentration in air expressed in part per million (ppm) in 10 minutes increment.
The continuous monitoring shall be processed during periods when children number exceeds 0.5 times the classroom theoretical headcount and is less than 1.5 times the room theoretical headcount. CO2 concentration are then classified into three categories:
- Values below 1,000 ppm
- CO2 values between 1,000 and 1,700 ppm
- Concentrations above 1,700 ppm