If a worker is routinely working an extra $30$ minutes each day and has an average exposure to xylene of $93ppm,$ adjust the allowable TLV based on an unusual work schedule. The TLV for xylene is $100ppm.$ Is there a problem here?

a$)$ If a worker is exposed to three different solvents during a de$-$greasing operation, determine whether or not the exposure to the mixture of solvent vapors exceeds the TLV$.$ The solvents are dichloromethane at a concentration of $)=(50ppm,$ toluene concentration $=)=(20ppm,$ and $1,1,2$ trichlorethane concentration of $)=(10ppm.$ Each of these solvents affect the central nervous system.

b$)$ If you discover that the worker also dips the parts in a dilute acid bath of acetic acid and is exposed to $4ppm,$ do you also need to include this exposure in your determination?

Calculate the TLV for a solvent mixture containing $25\%$ perchloroethylene $($TLV$=169\mathrm{.}5($:$m\frac{g}{m^3}\}$ toluene $)=(188\mathrm{.}3m\frac{g}{m^3},$ and $50\%$ xylene $).$

If a procedure requires a minimum sample volume of $960$ liters, how long must you run the pump at a flow rate of $2lpm?$

PLEASE CHECK AND HELP SOLVE THESE $)$: