Spatial analysis of the ecological effects of negative air ions in urban vegetated areas: A case study in Maiji, China

Negative air ions play an important role in absorbing dust, cleaning the air, and improving both the environment and human health. Based on data collected from the suburb of Maiji in 2013, using methods such as partial correlation analysis, semi-variation analysis, Kriging interpolation, re-classification and buffer analysis, this study analyzes the ecological effects of negative air ions in vegetated areas of the Maiji district. The results were as follows: (1) the concentration of negative air ions was negatively correlated with temperature, NO_x, SO₂ and aerosols, which had an influence on them; (2) the ratio of partial sill to sill was 83.7% and the ratio of nugget to sill was 16.25%; the negative air ions demonstrated a significant spatial autocorrelation, with an effect range of 262.929m; (3) the concentration of negative air ions in two-thirds of the study area was more than 1500unitcm^-3 and the average concentration was 2514unitcm^-3, which suggests good air quality; (4) the concentration of negative air ions was different among various types of vegetation; the average concentration was 3759unitcm^-3 in natural forests and their surroundings, with a maximum value of up to 5000unitcm^-3; the average concentration was 1984unitcm^-3 in economic forests, 1811unitcm^-3 in greenbelt, and 1634unitcm^-3 in farmlands. The effect of negative air ions in the Maiji district was outstanding at absorbing dust and cleaning the air, and was closely related to the vegetation structure, temperature, NO_x, SO₂, aerosols and altitude. These results can provide a theoretical foundation and technical guidance for planning and constructing an urban vegetated area in the Maiji district, which will improve the environmental quality of the city.