| a. |
Not to be exceeded
more than once per year |
| b. |
The objective is
attained when the annual arithmetic mean is less than or equal to 50
ug/m3. |
| c. |
The objective is
attained when the expected number of days per calendar year with a
24-hour average of 150 ug/m3 is equal to or less than 1. |
| d. |
The objective is
attained when the expected number of days per calendar year with the
maximum hourly average of 0.12 ppm is equal to or less than 1. |