"long-standing passion" is correct and usable in written English.
You can use it to refer to something that a person has felt strongly about for a long time. For example, "John has a long-standing passion for the outdoors and loves to go camping whenever he gets the chance."
Both countries have a long-standing passion for coloured stones, some of which are seen as bringing good luck (yellow sapphires in Hinduism, for instance).
Their decision to use a backup band on "Area 52" derived from a long-standing passion for Cuban music and a request by their record company for a further album while they were touring relentlessly for "11 11".
I love commissioning things, and I buy things beyond what I can physically afford.' She has a long-standing passion for Wyndham Lewis and has a couple of recently acquired 1932 drawings on the walls.
He is particularly indignant at the idea that he has operated a whites-only music policy on his Radio 1 show, pointing out his long-standing passion for reggae and African music and gospel and deep soul and numerous other categories of non-whites-only music I am unfamiliar with.
"While I do get quite a few people applying to my lab … very few have a long-standing passion to understand the aging brain," Barnes writes in an e-mail to Science Careers.
LitWorld grew out of a long-standing passion for literacy education, earlier contained in the educational consultancy LitLife.
Instead, having a baby seemed to sanction the positive aspects of the relationship, their long-standing friendship, passion, love, strong feelings, and a belief that they were meant for each other.
Apart from the difficulties of implementation (which nobody denied), the apparent reason for rejecting this scheme was the long-standing governmental passion for A-levels since the days of Kenneth Baker, repeatedly designated 'the gold standard' of our educational system.
There is a motor racing heritage here – 38,000 attended the WEC race in September – but a long-standing, deep-seated passion for Formula One in particular.
Here romantic (and utopian) ideas of passion and long-standing friendship played a major part – ideas that often characterized the abused women's stories about the beginning of their relationships (cf. 56).
Lee fills the movie with lyrical asides and violent passions, brings long-standing frustrations and anguish to light, and plants the characters firmly within the turbulent course of history.
