NEN 2795-1985 Air quality - Ambient air and indoor air Determination of the concentration of methanal (formaldehyde) - Pararosanilin photometric method
The standard applies to the measurement of the concentration of methanal in outdoor air and inhabited spaces in the concentration range from approximately 1 |Kj/m3 to 1000 ng/m3. The sampling period may not exceed 24 hours. Other aldehydes and nitrogen oxides can interfere with the determination, as can hydrogen sulphide. With the concentrations occurring in the open air, only NO2 is usually important as a dis urbance. In the method described here, methanol, ethanol, phenol, acetone, formic acid, acetic acid and ammonia do not interfere. Acetaldehyde interferes at a concentration greater than 0.1 MAC (18mg/m3). Note The interference caused by NO2 (present in the form of nitrite) can be prevented by adding sodium azide (see 7.3).
NEN 2795-1985 history
1985NEN 2795-1985 Air quality - Ambient air and indoor air Determination of the concentration of methanal (formaldehyde) - Pararosanilin photometric method