(CNN) -- The Barack Obama and Mitt Romney campaigns bought $45 million worth of commercials to run this week and into Election Day in key battleground states, according to a source tracking media buys, as spending records continue to be shattered.
And the buying is not over.
When spending by the campaigns, the parties, super PACs and the other independent committees is added together, it is estimated more than $1 billion will have been spent on ads by Election Day since April 10, when Mitt Romney became the presumptive Republican nominee.
More than $110 million was spent in battleground states in the Republican primary.
For ad time running from Monday through Election Day, the Obama campaign bought $24.2 million compared to $21.2 million for Romney -- as of late Wednesday, according to the media-tracking source. Both campaigns are continuing to purchase additional commercial time as they jockey for any last minute advantage.
While the campaigns and super PACs launched their carefully planned final ad blitz this week, they faced an unexpected uncertainty: Would a lot of the intended audience in certain key swing states not see their commercials because of Hurricane Sandy? While the Romney and Obama operations stopped fund raising in some of the areas affected by Sandy, they did not stop airing ads.
While power was lost in some areas in swing states Virginia and North Carolina, cutting off part of the potential audience, these states were not the hardest hit. They also saw an unexpected benefit: more people at home because of the storm exposed to the commercials and a larger audience for news shows, which carry a lot of political advertising.
The ad wars have been mostly fought in the same nine states for months: Colorado, Florida, Iowa, Nevada, New Hampshire, North Carolina, Ohio, Virginia and Wisconsin.
The three states in which the most ad dollars have been spent are Florida, Ohio, and Virginia because they are considered the most competitive battlegrounds. From Monday through Election Day in Ohio, Obama has so far bought $5.1 million in ads compared to $3.9 million for Romney. In Florida, Obama purchased $5 million vs. Romney's $3.7 million. And in an indication of how competitive Virginia is, both campaigns increased their ad spending there in the last 24 hours -- Romney now totals $3.6 million and Obama $3.3 million.
While Obama dramatically outspent his opponent throughout the summer and early fall, Romney has recently narrowed the difference when the two campaigns' ad spending is compared directly. The spending of Republican-leaning outside groups has kept Romney competitive throughout the fall. Two of the key super PACs backing Romney launched multimillion-dollar battleground ad campaigns this week with many of their ads hitting the president's economic record.
In total the Republican outside groups will have spent more than $310 million in the general election.
Because of the resources of such groups as Restore Our Future and American Crossroads, they have gone on the air in states where Romney's campaign was not running ads, thereby forcing the Obama re-election campaign to match, such as Michigan, where it has made a small buy of $329,000. In the closing days both campaigns are adding Pennsylvania to their ad rosters -- $1.4 million for Obama and $1 million for Romney.
Republicans argue they are trying to expand the map of where they are competing because of encouraging polls. Democrats counter they are in good position in the respective state polls, but they will match any new spending because they will not cede any ground.
Unlike past elections in which campaigns had to shift resources in the closing weeks and pull out of certain states, neither Obama nor Romney are in that position this year. Both decided not to take federal matching funds, meaning they have no required spending limits. They can buy as much television time in as many states as they want and as they can raise money for.
"They don't have to make as many tough, triage decisions," another source tracking this year's media spending said. "They have more money to spend, so they can play in more places."
Some TV markets are seeing as many as three times the number of ads they did four years ago.
While the total spending by the Romney campaign, GOP-leaning super PACs and other groups surpasses that of Democrats, the Obama campaign still enjoyed an advertising advantage this year.
Candidates pay less per ad than outside groups, so the president's re-election team, which has been able to drastically outspend the Romney campaign, has maximized the benefit of its dollars.
"Another reason is that daytime audiences, who are cheaper to reach than prime time or local news audiences, play more prominently in Obama's strategy. And a third reason is that the Obama campaign reserved a lot of ad time early, positioning them to benefit from some bargains along the way," said Elizabeth Wilner of CNN's ad consultant CMAG/Kantar Media.
Between April and this past Saturday, the Obama campaign alone aired 89,900 different ads in Ohio -- compared to a total of 81,854 commercials from Romney, the Republican National Committee and a variety of Republican-leaning groups there, according to data from CMAG.
But the campaigns and experts are not sure of the effect of the constant airing of these ads to the very audience they are trying to reach: voters in swing states, many of whom complain about the constant volley of attacks and counterattacks in the commercials.
"Just the number of spots gets to a certain level it all becomes background noise," one of the sources involved in ad buys told CNN. But campaigns believe it still may be the best way of trying to get their key messages out to the largest group.
CNN Political Research Director Robert Yoon contributed to this story