| Keyword | CPC | PCC | Volume | Score | Length of keyword |
|---|---|---|---|---|---|
| oxides of nitrogen sources | 1.54 | 0.6 | 4209 | 67 | 26 |
| oxides | 1.16 | 0.3 | 3517 | 86 | 6 |
| of | 1.35 | 0.7 | 118 | 72 | 2 |
| nitrogen | 0.88 | 0.9 | 5670 | 36 | 8 |
| sources | 1.16 | 0.3 | 2534 | 88 | 7 |
| Keyword | CPC | PCC | Volume | Score |
|---|---|---|---|---|
| oxides of nitrogen sources | 1.52 | 0.8 | 1622 | 44 |
| natural sources of nitrogen oxides | 0.72 | 0.3 | 6171 | 86 |
| what are the main sources of nitrogen oxides | 0.71 | 0.6 | 7571 | 44 |
| anthropogenic sources of nitrogen oxides | 0.44 | 0.9 | 2055 | 74 |
| major sources of nitrogen oxides | 1.6 | 0.5 | 6025 | 96 |
| top 3 sources of nitrogen oxides | 0.74 | 0.5 | 994 | 71 |
| human derived sources of nitrogen oxides | 1.74 | 0.5 | 3628 | 11 |
| sources of nitrogen dioxide | 0.84 | 0.1 | 6098 | 43 |
| major sources of nitrogen dioxide | 0.4 | 0.7 | 6970 | 53 |
| natural sources of nitrogen | 0.64 | 0.7 | 3342 | 11 |
| natural sources of nitric oxide | 0.68 | 0.8 | 9164 | 49 |
| natural sources of nitrous oxide | 1.56 | 0.4 | 8988 | 100 |
| main source of nitrogen dioxide | 1.93 | 1 | 2383 | 60 |
