The left shift key on my Macbook air

go to

>System Preferences/keyboard/input sources

verify the keyboard shows the correct region and when you hold down Left SHIFT you see the expected result on the character map

if you need to add or delete a region use the "+/-" icons

Quotidian9 wrote:

When I use the left shift key on my MacBook Air I get strange characters such as ÂÔ˝ÒÏ. Is this a keyboard setting issue or does the keyboard need repair.

That indicates your machine thinks the Option key is also being depressed at the same time. Repair is likely needed, but check by trying an external keyboard.