Hey Erik,
We don't actually have a settings for this yet but we are planning to add something similar into EasyBlog for what we have done in EasyDiscuss 4 so that you can fire up the email templates into a text editor.
At the moment, just edit the file /components/com_easyblog/themes/wireframe/emails/html/post.new.php and locate those text-align properties and change it to left.