NEW YORK (CNN) -- Some New Yorkers may want to reconsider exclaiming "Thank God" when arriving at their destination subway station beginning Monday.

Or at least that's what a coalition of eight atheist organizations are hoping, having purchased a month-long campaign that will place their posters in a dozen busy subway stations throughout Manhattan.

The advertisements ask the question, written simply over an image of a blue sky with wispy white clouds: "A million New Yorkers are good without God. Are you?"

On October 26, a dozen bustling New York City subway stations will be adorned with the ads as "part of a coordinated multi-organizational advertising campaign designed to raise awareness about people who don't believe in a god", according to a statement from the group, the Big Apple Coalition of Reason.