Compound PHP statement not working

I'm having issues with getting this bit of code working. I want if a certain page loads this template, and 1 of 4 possible categories are specified to then execute this action.

    if (is_page('combined-feed') and ($event_category=='179' || $event_category=='180' || $event_category=='181' || $event_category=='1028')) {
        $description = "description goes here"; 
    }

I tried using a structure similar to what is found in this thread, but have had no luck getting it to work. I know there's something going wrong with the or statements, but haven't been able to figure out how to structure the code any better.