A report on www.reven.de concerning currently applicable exposure limits relating to air pollution and air cleaners.
The fine dust pollution in the outside air has been a matter of discussion for several years now. Vehicle and industry emissions are in the focus of attention; the pollution of indoor air at workplaces is obviously neglected. The related discussions and regulations are becoming more and more grotesque: The Federal Emission Protection Act (BImSchV) stipulates limiting values for the outside air, which remain dramatically below the permissible WELs for indoor air. Obviously, nobody has noticed that until now. It is high time to point out this absurdity.
The term fine dust refers to the mass of all the particles with a diameter below 10 µm included in the total dust quantity. According to the findings of the World Health Organisation (WHO), respiratory and cardiovascular ailments increase with exposure to high concentrations of these fine particles. A WHO release states that “the public should be informed about this rapidly.”
In order to ensure health protection, exposure limits for outside air concentrations have been introduced by the authorities. Since 2005, a limiting value for daily exposure of 50 mg/m³, with maximum 35 exceptions per year, has been adopted Europe wide. The permissible average annual value was set to 40 µg/m³ in 2010. This code of standards is also included in the Federal Emission Protection Act (BImSchV) and has statutory force in Germany.
In the wake of this regulation, a country-wide measuring network has been created in Germany and bureaucracy gave birth to the badge system for urban traffic among other things.
And which are the limiting values applying to workplace air? According to the Technical Rules for Hazardous Materials TRGS 901, the permissible WEL is 10 mg/m³ of vapours and aerosols from cooling lubricants with a flash point above 100 °C that are used in metal processing in accordance with DIN 51385. The same limiting value also applies to processing machines with minimum lubrication. This limiting value is two hundred times higher (!) than that stipulated for the outside air by the Federal Emission Protection Act.
Obviously the TRGS WEL does not apply to fine dust in the common sense but cooling lubricant particles that are emitted in machining processes. The vapours and aerosols from cooling lubricants are quite similar to fine dust with respect to the particle sizes and the health hazards involved. With a diameter below 10 µm, these cooling lubricant particles intrude via the lungs into the vascular system. Therefore, they are considered to be particularly harmful.
In metal processing workshops, the air inside the shop is extracted frequently, cleaned and returned to the workshop. Experience shows that many of those air-cleaning systems hardly achieve a filter efficiency of 2 mg/m³. This concentration in the filtered air is still 40 times higher than the permissible limiting concentration for outdoor exposure. This means that factory workers are expected to bear concentrations of 10 mg or at least 2 mg of fine particles per m³ whereas people in urban areas are supposed to be threatened by ailments already at concentrations in excess of 40 µg/m³ (0.04 mg/m³). Professional associations should take the matter in hand without delay and update and harmonise the WEL regulations reasonably.
According to the Machinery Directive 98/37 EC, all necessary safety measures must be taken in order to protect the operators against hazards that cannot be eliminated. These hazards include oil and emulsion mists. The currently applicable WELs ridicule this regulation. How long will environmental industry accept these discrepancies?