It must be doubted that ventilation has any significant effect on the preservation of objects which themselves are the pollution source, such as stacks of acid paper, or decaying acetate film sheets.

如果文物本身就是污染物来源，例如酸性纸张、或者已经老化的醋酸纤维胶片，我们怀疑通风也不可能起到的很大作用。

youdao

Litmus paper turns red in the presence of an acid.

石蕊试纸遇到酸就变红。

《牛津词典》

In this paper, the process of polymalic acid (PMLA) synthesis was studied.

本文对合成聚苹果酸的过程进行了研究。

youdao

Serious collectors keep theirs in folders or envelopes made of acid-free paper.

FORBES: Magazine Article

Special care and white-glove handling will be needed because of the high acid content of the paper.

NPR: Juilliard Chairman Donates Trove of Rare Artifacts