<?xml version="1.0" encoding="utf-8"?><mads xmlns="http://www.loc.gov/mads/" xmlns:mods="http://www.loc.gov/mods/v3" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.loc.gov/mads/
mads.xsd"><authority><topic authority="http://AATesaurus.cultura.gencat.cat/aat/getty_en">sulfur oxide</topic></authority><related type="broader"><topic>sulfur compounds</topic></related><variant type="other"><topic>oxide, sulfur</topic></variant><variant type="other"><topic>sulfur oxides</topic></variant> <note xml:lang="en"><![CDATA[ Any of several gaseous compounds of sulfur and oxygen, most importantly sufur dioxide and sulfur trioxide. Sulfur oxides are responsible for about 18 percent of the total average pollutant content of air. ]]></note></mads>