There are a few ways to email volunteers.
From the Communication Center, click on create new communication and then click on "Use Advanced Segmentation" and selecting the appropriate box (or rather deselecting the unnecessary boxes.) From here you can send an email to all coaches but you cannot filter by Background Check or Concussion Certification status.
From the Volunteer Center click on the "Reminders" tab. From here you can send an email to those who are not in compliance.
Also, within this Volunteer Center, when you click on a group of your coaches, it will list them and their status, and then at the bottom of the screen there is an "Export" button.