Region | Species | Jan (%) | Feb (%) | Mar (%) | Apr (%) | May (%) | Oct (%) | Nov (%) | Dec (%) |
---|---|---|---|---|---|---|---|---|---|
NWIC | OC | 16 | 15 | 9 | 13 | 22 | 20 | 18 | 18 |
Sulfate |  − 10 |  − 12 |  − 16 |  − 13 |  − 6 |  − 8 |  − 9 |  − 9 | |
NEIC | OC | 21 | 17 | 10 | 11 | 19 | 24 | 24 | 23 |
Sulfate |  − 7 |  − 10 |  − 15 |  − 14 |  − 8 |  − 5 |  − 5 |  − 6 | |
SIC | OC | 15 | 12 | 10 | 13 | 19 | 21 | 22 | 21 |
Sulfate |  − 12 |  − 14 |  − 15 |  − 13 |  − 8 |  − 7 |  − 6 |  − 7 |