Weathers in air

20:48 Mar 3, 2017 

If only you had posted this question in English-Persian pair!

11:08 Mar 3, 2017 

Yes, the text is offered as some separate strings, i.e. actually not as an integrated text; thus, the intended meaning can be lost.

11:03 Mar 3, 2017 

In that case, the source text appears to be defective! One would not use the term 'weathering' to refer to simple disintegration of the type you describe.
Does the product actually catch fire on exposure to air? Or does it simply break down, crumble? Either way, 'weaethering' seems to me a technically inaccurate term to use.

11:02 Mar 3, 2017 

I wouldn't say that catching fire on contact with air is usually referred to as "weathering"! :o)

11:00 Mar 3, 2017 

To Tony M: I agree with you. As the product has already been introduced as flammable by exposure to air, it seems "disintegrate" is meant.

10:58 Mar 3, 2017 

I agree with Tony. A process often referred to as meteorisation. :o)

10:52 Mar 3, 2017 

'weathering' refers to ALL the deterioration that may be experienced due to exposure to the elements, e.g. corrosion, fading, colour change, embrittlement, peeling, etc. The source text seems to suggest that these effects take place merely on exposure to air, i.e. without the other factors usually involved such as rain, sunlight, UV, sea-spray, etc.
Without knowing which particular aspects of 'weathering' are involved, nor which substance, nor indeed what the wider context and purpose of this remark are, it is hard to give a better-targeted answer.