Objectives To investigate the polluted characteristics of 5 heavy metals (Mn, Cu, Zn, Cd and Pb) in inhalable particulate matter (PM₁₀) during heating period and non-heating period, analyze the different existing state and evaluate their bioavailability to provide basis for atmospheric heavy metal pollution abatement in Jiuyuan district of Baotou.

Methods Atmospheric particulates were collected in heating and non-heating period in Jiuyuan district of Baotou and BCR method was used for morphological classification to analyze the existing state of these heavy metals. The concentration of metals were measured by ICP-MS, the biological toxicity and bioavailability of metals were assessed by biological effectiveness coefficient.

Results The concentrations of five heavy metals in a partial existing state in heating period were higher than that in non-heating period, the differences were statistically significant. The distributions of five heavy metals were more in carbonate, oxidizable, reducible (F₂) and in organic, oxide and sulfide (F₃) forms. The biological effectiveness coefficient of Mn was high (0.348 1, 0.691 9), and that of Zn was low (0.042 2, 0.300 3).

Conclusions The contamination of heavy metals in Jiuyuan Baotou in heating period was more serious than that in non-heating period, and the toxic effect of Mn was high.