Question

disposable masks
half face masks
full face masks
which respiratory protection is best, depends on:
composition of the air
which substances are present in the air, and what are their health hazards.
limit air concentration
the amount of dust particles permitted. this is regulated by the government.
workplace conditions
e.g.: varying temperatures, ventilation, or lack of oxygen.
exposure time
filters become saturated after a while; substances are let through when this is the case.
note:
correct fit and regular maintenance are prerequisites for safe use.
filters have a limited service life.
on what does the appropriate respiratory protection depend?
the location of the workplace.
harmful substances in the air.
the exposure time to harmful substances.
the concentration of a specific substance in the air.
financial means.

Explanation:

The text states that the best respiratory protection depends on the composition of the air (which substances are present and their health - hazards), limit air concentration (amount of dust particles permitted), workplace conditions, and exposure time. It does not mention financial means or the location of the workplace as factors. The presence of harmful substances in the air, exposure time to harmful substances, and the concentration of a specific substance in the air are all mentioned as relevant factors.

Answer:

B. Harmful substances in the air, C. The exposure time to harmful substances, D. The concentration of a specific substance in the air