3M 8210Plus User Instructions page 7

Storage Conditions and Shelf Life
Before use, store respirators in the original packaging away from
contaminated areas, dust, sunlight, extreme temperatures, excessive
moisture and damaging chemicals. When stored in accordance with
temperature and humidity conditions specified below, the product may
be used until the "use by" date specified on packaging. Always inspect
product and conduct a user seal check before use as specified in the
User Instructions. If you cannot achieve a proper seal, do not use
the respirator.
+86˚F
+30˚C
-4˚F
-20˚C
<80%
End of Shelf Life Use
respirators before the "use by" date specified
on packaging
Storage Temperature Range
Storage Maximum Relative Humidity <80% RH