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 produces the polysulfanes, HS where x = 2, 3, and 4. Ultimately, reduction of sulfur produces sulfide salts: The interconversion of these species is exploited in the sodium-sulfur battery. The radical anion S gives the blue color of the mineral lapis lazuli. The principal sulfur oxides are obtained by burning sulfur: Multiple sulfur oxides are known; the sulfur-rich oxides include sulfur monoxide, disulfur monoxide, disulfur dioxides, and higher oxides containing peroxo groups. Sulfur forms sulfur oxoacids, some of which cannot be isolated and are only known through the salts. Sulfur dioxide and sulfites () are related to the unstable sulfurous