For school, office, or car

Place in a medium or large fanny pack: 

bullet12-hour light stick
bullet1200 calorie food bar
bullet3 or more water pouches
bulletPocket first aid kit
bulletThermal blanket
bulletRain poncho
bulletWet wipes
bulletPocket knife
bulletDust mask
bulletID such as a business card
bulletHome and emergency contact information
bulletCoins for a phone call or a non-expiring phone card
bulletList of pack contents
bulletWork gloves, if there is room

Dust mask, ID, contact information, coins/phone card and list should be kept in resealable plastic bags.  Food bars can be larger if there is room in the pack. 

Keep the pack in a school locker, desk or filing cabinet drawer, in a car trunk or glove compartment or anywhere else that is accessible when away from home.