Thanks @RW9.
 
This does indeed work for the data sample I posted above. However, I may have left out some key information. 
 
What I'm trying to do is this : only affect an NO2 reading to the seconds of the previous minute, so that, for example, during a 10 minute  I would have a different N02, HUMIDITY and TEMP reading for every minute which would then be passed on to the seconds of the previous minute a total of ten times. Here's some more sample data to make this a little more clear:
 
| ID | LAT        | LONG        | DateTime         | NO2   | HUMIDITY | TEMP |
|----|------------|-------------|------------------|-------|----------|------|
| 1  | 45.481746N | 073.571211W | 28SEP15:07:21:26 |       |          |      |
| 1  | 45.481681N | 073.571095W | 28SEP15:07:21:29 |       |          |      |
| 1  | 45.481661N | 073.571056W | 28SEP15:07:21:30 |       |          |      |
| 1  | 45.481619N | 073.570981W | 28SEP15:07:21:32 |       |          |      |
| 1  | 45.481538N | 073.570833W | 28SEP15:07:21:36 |       |          |      |
| 1  | 45.481518N | 073.570798W | 28SEP15:07:21:37 |       |          |      |
| 1  | 45.481498N | 073.570761W | 28SEP15:07:21:38 |       |          |      |
| 1  | 45.481478N | 073.570726W | 28SEP15:07:21:39 |       |          |      |
| 1  | 45.481458N | 073.570691W | 28SEP15:07:21:40 |       |          |      |
| 1  | 45.481439N | 073.570656W | 28SEP15:07:21:41 |       |          |      |
| 1  | 45.481419N | 073.570621W | 28SEP15:07:21:42 |       |          |      |
| 1  | 45.481401N | 073.570588W | 28SEP15:07:21:43 |       |          |      |
| 1  | 45.481383N | 073.570553W | 28SEP15:07:21:44 |       |          |      |
| 1  | 45.481364N | 073.570520W | 28SEP15:07:21:45 |       |          |      |
| 1  | 45.481346N | 073.570486W | 28SEP15:07:21:46 |       |          |      |
| 1  | 45.481328N | 073.570454W | 28SEP15:07:21:47 |       |          |      |
| 1  | 45.481309N | 073.570421W | 28SEP15:07:21:48 |       |          |      |
| 1  | 45.481291N | 073.570389W | 28SEP15:07:21:49 |       |          |      |
| 1  | 45.481275N | 073.570358W | 28SEP15:07:21:50 |       |          |      |
| 1  | 45.481256N | 073.570326W | 28SEP15:07:21:51 |       |          |      |
| 1  | 45.481239N | 073.570295W | 28SEP15:07:21:52 |       |          |      |
| 1  | 45.481223N | 073.570263W | 28SEP15:07:21:53 |       |          |      |
| 1  | 45.481204N | 073.570233W | 28SEP15:07:21:54 |       |          |      |
| 1  | 45.481188N | 073.570203W | 28SEP15:07:21:55 |       |          |      |
| 1  | 45.481171N | 073.570173W | 28SEP15:07:21:56 |       |          |      |
| 1  | 45.481156N | 073.570143W | 28SEP15:07:21:57 |       |          |      |
| 1  | 45.481140N | 073.570113W | 28SEP15:07:21:58 |       |          |      |
| 1  | 45.481123N | 073.570083W | 28SEP15:07:21:59 |       |          |      |
| 1  | 45.481108N | 073.570054W | 28SEP15:07:22:00 | 0.007 | 55.9     | 22.4 |
| 1  | 45.481091N | 073.570026W | 28SEP15:07:22:01 |       |          |      |
| 1  | 45.481076N | 073.569998W | 28SEP15:07:22:02 |       |          |      |
| 1  | 45.481059N | 073.569970W | 28SEP15:07:22:03 |       |          |      |
| 1  | 45.481044N | 073.569941W | 28SEP15:07:22:04 |       |          |      |
| 1  | 45.481030N | 073.569913W | 28SEP15:07:22:05 |       |          |      |
| 1  | 45.481014N | 073.569886W | 28SEP15:07:22:06 |       |          |      |
| 1  | 45.480999N | 073.569860W | 28SEP15:07:22:07 |       |          |      |
| 1  | 45.480985N | 073.569833W | 28SEP15:07:22:08 |       |          |      |
| 1  | 45.480969N | 073.569806W | 28SEP15:07:22:09 |       |          |      |
| 1  | 45.480956N | 073.569780W | 28SEP15:07:22:10 |       |          |      |
| 1  | 45.480941N | 073.569753W | 28SEP15:07:22:11 |       |          |      |
| 1  | 45.480928N | 073.569728W | 28SEP15:07:22:12 |       |          |      |
| 1  | 45.480913N | 073.569703W | 28SEP15:07:22:13 |       |          |      |
| 1  | 45.480900N | 073.569676W | 28SEP15:07:22:14 |       |          |      |
| 1  | 45.480886N | 073.569651W | 28SEP15:07:22:15 |       |          |      |
| 1  | 45.480871N | 073.569628W | 28SEP15:07:22:16 |       |          |      |
| 1  | 45.480858N | 073.569603W | 28SEP15:07:22:17 |       |          |      |
| 1  | 45.480845N | 073.569578W | 28SEP15:07:22:18 |       |          |      |
| 1  | 45.480831N | 073.569555W | 28SEP15:07:22:19 |       |          |      |
| 1  | 45.480818N | 073.569529W | 28SEP15:07:22:20 |       |          |      |
| 1  | 45.480804N | 073.569506W | 28SEP15:07:22:21 |       |          |      |
| 1  | 45.480793N | 073.569483W | 28SEP15:07:22:22 |       |          |      |
| 1  | 45.480779N | 073.569460W | 28SEP15:07:22:23 |       |          |      |
| 1  | 45.480766N | 073.569436W | 28SEP15:07:22:24 |       |          |      |
| 1  | 45.480755N | 073.569413W | 28SEP15:07:22:25 |       |          |      |
| 1  | 45.480741N | 073.569391W | 28SEP15:07:22:26 |       |          |      |
| 1  | 45.480729N | 073.569368W | 28SEP15:07:22:27 |       |          |      |
| 1  | 45.480718N | 073.569346W | 28SEP15:07:22:28 |       |          |      |
| 1  | 45.480706N | 073.569325W | 28SEP15:07:22:29 |       |          |      |
| 1  | 45.480693N | 073.569303W | 28SEP15:07:22:30 |       |          |      |
| 1  | 45.480681N | 073.569281W | 28SEP15:07:22:31 |       |          |      |
| 1  | 45.480669N | 073.569260W | 28SEP15:07:22:32 |       |          |      |
| 1  | 45.480658N | 073.569238W | 28SEP15:07:22:33 |       |          |      |
| 1  | 45.480646N | 073.569216W | 28SEP15:07:22:34 |       |          |      |
| 1  | 45.480636N | 073.569196W | 28SEP15:07:22:35 |       |          |      |
| 1  | 45.480624N | 073.569176W | 28SEP15:07:22:36 |       |          |      |
| 1  | 45.480613N | 073.569155W | 28SEP15:07:22:37 |       |          |      |
| 1  | 45.480601N | 073.569134W | 28SEP15:07:22:38 |       |          |      |
| 1  | 45.480591N | 073.569115W | 28SEP15:07:22:39 |       |          |      |
| 1  | 45.480579N | 073.569095W | 28SEP15:07:22:40 |       |          |      |
| 1  | 45.480570N | 073.569075W | 28SEP15:07:22:41 |       |          |      |
| 1  | 45.480558N | 073.569056W | 28SEP15:07:22:42 |       |          |      |
| 1  | 45.480548N | 073.569036W | 28SEP15:07:22:43 |       |          |      |
| 1  | 45.480536N | 073.569016W | 28SEP15:07:22:44 |       |          |      |
| 1  | 45.480526N | 073.568998W | 28SEP15:07:22:45 |       |          |      |
| 1  | 45.480515N | 073.568978W | 28SEP15:07:22:46 |       |          |      |
| 1  | 45.480504N | 073.568960W | 28SEP15:07:22:47 |       |          |      |
| 1  | 45.480494N | 073.568940W | 28SEP15:07:22:48 |       |          |      |
| 1  | 45.480483N | 073.568921W | 28SEP15:07:22:49 |       |          |      |
| 1  | 45.480473N | 073.568903W | 28SEP15:07:22:50 |       |          |      |
| 1  | 45.480463N | 073.568883W | 28SEP15:07:22:51 |       |          |      |
| 1  | 45.480453N | 073.568864W | 28SEP15:07:22:52 |       |          |      |
| 1  | 45.480443N | 073.568846W | 28SEP15:07:22:53 |       |          |      |
| 1  | 45.480246N | 073.568474W | 28SEP15:07:22:54 |       |          |      |
| 1  | 45.480086N | 073.568175W | 28SEP15:07:22:55 |       |          |      |
| 1  | 45.479948N | 073.567930W | 28SEP15:07:22:56 |       |          |      |
| 1  | 45.479838N | 073.567730W | 28SEP15:07:22:57 |       |          |      |
| 1  | 45.479751N | 073.567563W | 28SEP15:07:22:58 |       |          |      |
| 1  | 45.479685N | 073.567424W | 28SEP15:07:22:59 |       |          |      |
| 1  | 45.479631N | 073.567313W | 28SEP15:07:23:00 | 0.037 | 49.4     | 21.8 |
 
In this data I have data for NO2, HUMIDITY and TEMP at two different minutes (7:22 and 7:23). I need to move these "up" to the seconds of the previous minute. Logically, with your code, the readings from 7:22:00(HH:MM:SS) are also affected to the seconds that should have values from the readings at 7:23:00.
I know your leaving for the day but when you do have time, I would love to see if you could help me out a little more. Till then, I'll mess around some more. Much appreciated, by the way!