PM10-2.5 Distribution Statistics for 2009
Table 1. The following table shows summary statistics for PM10-2.5. The first column identifies the county and site name; the second column shows the number of valid samples; the third column shows the percentage of these samples for which negative concentration values were computed; the 4th through 7th columns show indicated percentile statistics, 25%, 50%, 75% and 98%; and the 8th column shows the arithmetic mean value.
| County / Site | No. Obs. | % neg. | 25th % | 50th % | 75th % | 98th % | Arith. Mean |
|---|---|---|---|---|---|---|---|
| Mecklenburg / Garinger | 112 | 0.0 | 4.02 | 5.20 | 6.82 | 10.78 | 5.55 |
| Mecklenburg / Montclaire 1 | 110 | 0.0 | 4.20 | 5.85 | 8.30 | 16.93 | 6.96 |
| Mecklenburg / Montclaire 2 | 54 | 0.0 | 3.65 | 6.20 | 8.75 | 16.67 | 6.67 |
| Wake / Millbrook | 101 | 3.0 | 2.78 | 4.96 | 7.05 | 13.64 | 5.26 |
| Catawba / Hickory* | 58 | 5.2 | 3.13 | 6.03 | 9.36 | 16.11 | 6.59 |
| Guilford / Greensboro* | 54 | 11.1 | 1.69 | 4.47 | 5.62 | 11.32 | 3.89 |
| Cumberland / Fayetteville* | 53 | 15.1 | 1.82 | 3.76 | 7.04 | 10.52 | 4.08 |
* Computed using nonmatching PM10 and PM2.5 monitor methods.