Minnesota Administrative Rules

7017.1200 COMS MONITORING DATA.

Subpart 1.

Averaging periods.

All COMS data must be reduced to six-minute averages.

Subp. 2.

Data points.

Compliance must be calculated from all data points collected in the averaging period by the COMS. A six-minute average is valid only if it contains data from at least five of the minutes within the averaging period.

Subp. 3.

Opacity data reduction procedures.

Six-minute opacity averages must be calculated as follows: each one-minute period, the one-minute average opacity value must be determined by summing the opacity values of the individual data points collected by the COMS and dividing that sum by the number of data points collected. This is the one-minute average opacity value. Next, the sum of the individual one-minute averages in the applicable averaging period must be determined and divided by the number of one-minute averages taken. The resulting average must be rounded to the nearest one percent opacity. The resulting value is the six-minute opacity average that shall be recorded by the monitoring system. There are ten individual six-minute averaging periods in each hour. The first six-minute period starts at the beginning of the clock hour and ends at the beginning of minute six of the clock hour. The second six-minute period immediately follows the first, and the pattern continues through the last of the ten six-minute periods in a clock hour.

Subp. 4.

Opacity exceedance.

An opacity exceedance has occurred if, having taken any allowable excursions into account, any six-minute average exceeds the applicable opacity standard. Exceedances must be expressed as the number of nonoverlapping six-minute averages that exceeded the standard.

Statutory Authority:

MS s 116.07

History:

23 SR 1764

Published Electronically:

November 29, 2007