Environmental issues in Syria Attacks on oil refineries can cause oil fires which release harmful chemicals into the air, such as sulfur dioxide, nitrogen dioxide, carbon monoxide and polycyclic aromatic hydrocarbons (PAHs). The sulphur and nitrogen compounds are linked to acid rain which can have dire impacts on vegetation as well as cause soil acidification. PAHs persist in the environment for long periods of time and are known carcinogens. Syria also extracts heavy crude oil, which generally has a higher proportion of noxious substances, including heavy metals, making it especially dangerous when these substances seep into the soil. Syria has two oil refineries. The
Sulfur dioxide action of hot concentrated sulfuric acid on copper turnings produces sulfur dioxide. Sulfite results from the reaction of aqueous base and sulfur dioxide. The reverse reaction involves acidification of sodium metabisulfite: Treatment of basic solutions with sulfur dioxide affords sulfite salts (e.g. sodium sulfite): Featuring sulfur in the +4 oxidation state, sulfur dioxide is a reducing agent. It is oxidized by halogens to give the sulfuryl halides, such as sulfuryl chloride: Sulfur dioxide is the oxidising agent in the Claus process, which is conducted on a large scale in oil refineries. Here, sulfur dioxide is reduced by hydrogen sulfide to