An analysis of Tianjin's air pollutants has identified dust as the main component of the city's smog.

Tianjin, about 100 kilometers southeast of Beijing, is the second city after the capital to release an analysis of its fine particulate matter, or PM2.5.

The analysis, released over the weekend, comes after the national environmental authority asked that China's five major cities and 30 other municipalities and capitals, excluding Lhasa, present their analyses before the end of 2014.