U.S. Geological Survey Open-File Report 09-0346
Trends in Precipitation Chemistry in the United States, 1983-1994: An Analysis of the Effects in 1995 of Phase I of the Clean Air Act Amendments of 1990, Title IV

Table 3. Coincidence of significantly (p<0.05) decreasing sulfate concen- trations with significantly decreasing hydrogen ion concen- trations from 1983 through 1994.


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| Region     Site       p(SO4)        p(H)   |
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|  NE        wi28       0.0001       0.0013  |
|            ny10       0.0001       0.0056  |
|            wv04       0.0001       0.0067  |
|            in20       0.0003               |
|            mi26       0.0004       0.0364  |
|            wi37       0.0025               |
|            ny52       0.0031       0.0055  |
|            mi99       0.0039               |
|            mi09       0.0040       0.0302  |
|            ky22       0.0052       0.0422  |
|            il19       0.0055       0.0163  |
|            ny98       0.0075       0.0205  |
|            mi98       0.0127       0.0057  |
|            pa15       0.0146       0.0029  |
|            wi99       0.0216               |
|            va28       0.0235       0.0491  |
|            wi36       0.0283               |
|            il11       0.0318       0.0223  |
|            in41       0.0366       0.0321  |
|            il63       0.0367               |
|            mi53       0.0406       0.0211  |
|            me98       0.0417               |
|            in34       0.0437       0.0013  |
|                                            |
|           16 of 23 sites (70%)             |
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|  SE        ms10       0.0035               |
|            nc25       0.0083               |
|            tn00       0.0100               |
|            al10       0.0196               |
|            ms30       0.0251               |
|            nc03       0.0314               |
|                                            |
|            0 of 6 sites (0%)               |
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|  West      wy02       0.0001       0.0001  |
|            or10       0.0001               |
|            mn16       0.0003               |
|            ca45       0.0005       0.0347  |
|            co98       0.0005               |
|            mo03       0.0006       0.0068  |
|            mt05       0.0006               |
|            az99       0.0007       0.0002  |
|            ar27       0.0019               |
|            ca98       0.0025               |
|            nm07       0.0025               |
|            mn18       0.0035               |
|            co19       0.0036               |
|            nm09       0.0037       0.0104  |
|            az03       0.0040               |
|            co22       0.0047       0.0154  |
|            or02       0.0057               |
|            or97       0.0064       0.0066  |
|            co99       0.0081               |
|            mn27       0.0084               |
|            ca88       0.0162       0.0493  |
|            nd11       0.0196               |
|            co00       0.0208               |
|            wy99       0.0218               |
|            la12       0.0230               |
|            nd07       0.0306               |
|            ne15       0.0326       0.0287  |
|            or98       0.0385               |
|            ca42       0.0429       0.0044  |
|            la30       0.0453               |
|                                            |
|           10 of 30 sites (33%)             |
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| 26 of 39 sites with decreasing H+ also     |
| had decreasing SO42-                       |
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| 26 of 59 sites with decreasing SO42-       |
| also had decreasing H+                     |
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Last Update: 1536 08JUL96 kjl