"affluent in" is correct and usable in written English.
You can use it to describe being well-endowed with something. For example, "The conference room was affluent in natural light."
THE CROWD Young, hip and affluent, in smart-casual dress.
Forbes regularly cites the zip code for Alpine as the most affluent in the United States.
The surrounding residential neighborhood is one of the most affluent in Queens.
Its ZIP code, 11568, is ranked as the 10th most affluent in the country.
The seat is also one of the most affluent in the UK.
Their salaries of $300 to $700 a month made them affluent in their villages.
He grew up relatively affluent in Manhattan, the son of an advertising executive.
Q. Seems like you're filling a need of providing homes for the less affluent in the city.
Here we need to pay attention to the changing lives of the affluent — in particular, their work habits.
Last year, American Demographics magazine identified Old Westbury's ZIP code, 11568, as the 10th most affluent in the United States.
They explained: "That excess reflects the disproportionate presence of the affluent in such hazardous roles as pilots or infantry captains and lieutenants.
