shelter in place
If you are outdoors and you smell a strong chemical odor, protect yourself by immediately going inside the nearest building, home or vehicle. Most chemical releases will last only a few minutes and staying inside should be adequate for your protection.
This is called Shelter in Place and is the best way to protect yourself and your family in the event of an accidental chemical release. This works because the outside air does not mix quickly with the air in these spaces when they are closed or sealed. Shelter in Place protects you from the most toxic vapors as the cloud passes.