| Total requests for Apr 2011: 3,797 |
| Unique requests | Total requests | Query | Documents returned |
| 40 | 62 | R744 | 53,352 |
| 25 | 39 | cfc | 40,057 |
| 22 | 29 | certification | 4,160 |
| 22 | 25 | 608 test | 13,503 |
| 21 | 25 | 269A | 29,789 |
| 16 | 26 | HCFC | 31,280 |
| 14 | 23 | section 609 | 41,802 |
| 13 | 23 | permitted releases | 5,059 |
| 12 | 16 | snap | 20,730 |
| 12 | 13 | 608 | 137 |
| 11 | 11 | ozone depletion | 260 |
| 10 | 15 | fines | 48,269 |
| 8 | 12 | HFC132 | 32,350 |
| 8 | 10 | global warming | 32,661 |
| 7 | 13 | refrigerant | 84,412 |
| 7 | 10 | Earth day | 86,644 |
| 7 | 8 | r134a | 37 |
| 7 | 8 | Montreal protocol | 12,313 |
| 6 | 13 | smuggleing | 222 |
| 6 | 11 | freon | 95,019 |
| 6 | 8 | gwp | 43,756 |
| 6 | 8 | epa certification | 84,180 |
| 6 | 6 | forms | 324 |
| 6 | 6 | 609 | 99 |
| 5 | 16 | stratosphere | 31,971 |
| 5 | 10 | j2099 | 72,070 |
| 5 | 8 | R410a | 86,533 |
| 5 | 8 | R404a | 86,401 |
| 5 | 7 | 609 license | 92,020 |
| 5 | 6 | what is ozone | 830 |
| 5 | 6 | ozone hole | 310 |
| 5 | 6 | R-134a | 18,872 |
| 5 | 5 | montreal | 217 |
| 5 | 5 | halon | 78 |
| 5 | 5 | 1234yf | 24 |
| 4 | 11 | retrofit | 61,720 |
| 4 | 8 | log | 46,154 |
| 4 | 7 | radon | 105,142 |
| 4 | 6 | kyoto protocol | 56,506 |
| 4 | 5 | uv radiation | 19,972 |
| 4 | 5 | technician certification | 73,476 |
| 4 | 4 | uv index | 70 |
| 4 | 4 | test results | 229 |
| 4 | 4 | study guide | 172 |
| 4 | 4 | acid rain | 7 |
| 4 | 4 | Global Warming Potential | 183 |
| 3 | 10 | reclaimers | 76,640 |
| 3 | 10 | practice test | 66,880 |
| 3 | 10 | REFRIGERATION CERTIFICATE | 106,401 |
| 3 | 9 | hvac | 93,796 |
| 3 | 7 | hot shot | 165,586 |
| 3 | 6 | climate change | 33,827 |
| 3 | 5 | what can individuals do | 210 |
| 3 | 5 | nitinol stent | 0 |
| 3 | 5 | ari 700-2008 | 6 |
| 3 | 5 | R407F | 69,999 |
| 3 | 4 | testing sites | 87,185 |
| 3 | 4 | recovery | 171 |
| 3 | 4 | performax lt | 0 |
| 3 | 4 | frigc-fr-12 | 82,004 |
| 3 | 4 | chlorofluorocarbons | 80,565 |
| 3 | 4 | De minimis release | 24,256 |
| 3 | 4 | De Minimus | 0 |
| 3 | 3 | texas | 74 |
| 3 | 3 | test locations | 240 |
| 3 | 3 | san diego | 41 |
| 3 | 3 | rewards | 19 |
| 3 | 3 | recoveryform | 3 |
| 3 | 3 | nPB | 8 |
| 3 | 3 | n-propyl bromide | 15 |
| 3 | 3 | mvac | 57 |
| 3 | 3 | legal implications | 32 |
| 3 | 3 | leak | 200 |
| 3 | 3 | greenhouse effect | 163 |
| 3 | 3 | fines for misuse | 3 |
| 3 | 3 | epa test results | 121 |
| 3 | 3 | envirosafe | 0 |
| 3 | 3 | cfc testing | 112 |
| 3 | 3 | cards | 22 |
| 3 | 3 | carbon dioxide | 192 |
| 3 | 3 | SEER13 | 15 |
| 3 | 3 | ODS | 219 |
| 3 | 3 | Equipment certification forms | 103 |
| 3 | 3 | EPA practice tests | 241 |
| 3 | 3 | De minimis | 9 |
| 2 | 12 | smoking | 9,111 |
| 2 | 12 | alternative refrigerants | 91,373 |
| 2 | 11 | hfo1234yf | 133,300 |
| 2 | 10 | pollution | 16,730 |
| 2 | 6 | low pressure refrigerant | 115,735 |
| 2 | 6 | law | 55,644 |
| 2 | 6 | 64742-94-5 | 882 |
| 2 | 5 | replacement for R22 | 21,823 |
| 2 | 5 | recovery equipment | 66,785 |
| 2 | 5 | microwave | 3 |
| 2 | 5 | electrical | 66,680 |
| 2 | 5 | biology | 142 |
| 2 | 4 | what6 is the current ozone level where you live | 38,017 |
| 2 | 4 | what is a good ozone | 24,206 |
| 2 | 4 | retrofitting guide | 47 |
| 2 | 4 | r12 replacement | 91,742 |
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