Editing Geography of Uzbekistan (section)

===Air pollution===
Poor water management and heavy use of agricultural chemicals also have polluted the air.<ref name=":0" /> Salt and dust storms and the spraying of pesticides and defoliants for the cotton crop have led to severe degradation of air quality in rural areas.<ref name=":0" />

In urban areas, factories and auto emissions are a growing threat to air quality.<ref name=":0" /> Fewer than half of factory smokestacks in Uzbekistan are equipped with filtration devices, and none has the capacity to filter gaseous emissions.<ref name=":0" /> In addition, a high percentage of existing filters are defective or out of operation.<ref name=":0" /> Air pollution data for Tashkent, Farghona, and Olmaliq show all three cities exceeding recommended levels of nitrous dioxide and particulates.<ref name=":0" /> High levels of heavy metals such as lead, nickel, zinc, copper, mercury, and manganese have been found in Uzbekistan's atmosphere, mainly from the burning of fossil fuels, waste materials, and ferrous and nonferrous metallurgy.<ref name=":0" /> Especially high concentrations of heavy metals have been reported in Toshkent Province and in the southern part of Uzbekistan near the Olmaliq Metallurgy Combine.<ref name=":0" /> In the mid-1990s, Uzbekistan's industrial production, about 60% of the total for the Central Asian nations excluding Kazakhstan, also yielded about 60% of the total volume of Central Asia's emissions of harmful substances into the atmosphere.<ref name=":0" /> Because automobiles are relatively scarce, automotive exhaust is a problem only in Tashkent and Farghona.<ref name=":0" />