Adverts showing how much money Yorkshire Air Ambulance needs to raise to carry on its work are to appear on buses across Yorkshire.
Almost 500 advertising spots have been donated to the charity by CBS Outdoor which operates the commercial space.
The adverts went live on December 23.
They read: “We need to raise £9,990 every day to help save more lives. Please visit www.yaa.org.uk to help.”
To increase the visibility of the campaign, the charity is now asking people to take photos if they see one of the bus adverts and share it on social media using the hashtag #YAAonthebuses.
A spokesman for YAA said: “This is such an amazing opportunity for YAA to raise awareness across the whole of Yorkshire.
“We want you to send in a picture of where you have spotted our adverts .
“You can be as creative as you like, if you want to be in the picture or just send the advert, but be sure to hashtag and let us know the route you’ve seen it on.”