Lawnmowers are ruining my sleep and work, any suggestions?

I have a night job. My typical 'morning' alarm is set for 4pm since I work from 5pm-3am. I live in an apartment and lawnmowers are the bane of my existence. I'm SO sound sensitive that they wake me up every time, even if they're across the complex, then I stay awake until they get all the way to my building and then leave again. This is seriously negatively affecting my work and I get super stressed and so angry every time it happens. The next day I'm basically a ball of rage who can't concentrate on any project that needs to get done. Does anyone have any suggestions? I sleep with a fan on for background noise, but it doesn't help much, and I can't use ear plugs since any I've found are far too uncomfortable for sleeping.