I've been getting fans to optin to my list based on the topic, for example "cute dogs" and sending them newsletter style emails that relate to dogs, and having a featured product listed in the email. It doesn't always get orders, but it does occasionally, but I've yet to get anyone unsubscribing since I always only post relating to the topic.
In your case, since it's "City" based, you can still consider having them opt-in for notification for coupons and discounts from companies within that local city. People love to get discounts on stuff, and if you can offer them that as incentive for joining your list, you could get quite a few of those 44k signing up to your list. Just make sure you actually deliver on your promise and only mail them once a week or so, and you should be fine.