As a landlocked and mountainous country, Mongolia’s main means of transportation are road, rail, and air transport. Mobility in urban areas relies only on road transport. As of 2002, the total road network of the country measured 49,250 kilometers (km), of which only 3.6% was paved (IRF 2004). The country has a single 1,815 km-long main-line railway and an additional 200 km of feeder lines and sidetracks. Th e railways are mainly used for freight transportation (UNEP 2002).

There are more than 4,000 km of motor roads in Mongolia, of which 3,325 km are improved roads and 1,471 km are paved with hard cover. Most of the passenger trips in Mongolia are carried by on-road transportation. The vehicle fleet of the capital city has grown more than twice the total number (from 30,000 to 75,000) in the period 1995–2005. Sixty percent of the motor vehicle fleet in Mongolia is found in Ulaanbaatar. Most of these vehicles are second hand; about 80% of them do not meet fuel consumption or emission standards and about 54% of the vehicle fl eet is 11 years or older (Bat-Ochir 2006). Public transportation in Ulaanbaatar and other urban centers is mainly by bus, microbus, (van), trolleybus, and taxis.

Emissions inventories of air pollutants are compiled annually by the National Agency for Meteorology, Hydrology, and Environmental Monitoring (NAMHEM) of the Ministry of Nature and Environment. Th e inventory of emissions covers the following air pollutants: PM10, PM2.5, Nitrogen oxides (NOx), nonmethane volatile organic compounds (NMVOC), and Carbon monoxide (CO) from two sources (forest and grass fi res, and vehicles).

Sources of air pollution include emissions from motor vehicles; stationary sources—CHP, heat-only boilers (HOB), and industry; and area sources—household stoves, refuse burning, road dust, and sandstorms (World Bank 2004). One of the main problems is caused by use of low-level technologies and inadequate pollution control devices used in small- and medium-sized industries. Th is is further aggravated by the fact that operators do not have suffi cient training in the heating stations using coal as fuel source.

About 5.7 million t of coal and 160 million cubic meters of wood are used for energy generation, heating, and cooking in Mongolia annually. Th e three CHP in Ulaanbaatar, which consume about 5 million t of coal per year, and the 250 HOB, which burn an annual average of 400,000 t of coal, release emissions, including Sulfur dioxide (SO2), PM, and Nitrogen dioxide (NO2) in the air (World Bank 2004).

About half of Ulaanbaatar’s population lives in gers, which use wood and coal for cooking and heating without any pollution control devices whatsoever, are considered to substantially contribute to urban ambient air pollution.