Effects of different habitats in the Yellow River Delta coastal wetlands on atmospheric particulate matter deposition

Objective To investigate the effects of different habitats in the Yellow River Delta coastal wetlands on atmospheric particulate matter deposition and to clarify the responses of deposition fluxes to variations in surface environmental and meteorological conditions.

Method Data on atmospheric particulate matter concentrations, meteorological variables, and tidal flat water levels were collected during April 2025 using three multi-level automatic meteorological observation systems deployed at the Tidal Flat Station, Vegetation Station, and Tidal Creek Station. Differences in deposition fluxes among habitats were assessed using Kruskal-Wallis tests with Dunn’s post-hoc comparisons, while relationships with environmental factors were analyzed using Spearman’s rank correlation. On this basis, a generalized additive model (GAM) was further employed to quantify the relative contributions of wind speed, wind direction, relative humidity, tidal flat water level, and temperature, and to characterize nonlinear responses of deposition fluxes to these factors.

Result Significant differences in particulate matter deposition fluxes were observed among habitats (p < 0.001). The Vegetation Station exhibited higher deposition fluxes and greater stability for PM_2.5 and PM₁₀, whereas the Tidal Flat Station showed higher TSP deposition fluxes with greater variability. Relative humidity was identified as the dominant factor affecting particulate matter deposition. Its contributions to PM_2.5 and PM₁₀ deposition at the Vegetation Station reached 23.53% and 22.91%, respectively, and relative humidity exhibited significant nonlinear effects on deposition fluxes across multiple habitats. In addition, wind speed and wind direction played important roles in regulating deposition, with higher relative humidity conditions and southeasterly winds synergistically favoring particulate matter deposition.

Conclusion Different habitats in the Yellow River Delta coastal wetlands can regulate atmospheric particulate matter deposition processes by altering near-surface micro-meteorological conditions. Relative humidity plays a dominant role, followed by wind speed and wind direction, and different habitats exhibit distinct deposition regulation mechanisms. Significant nonlinear relationships were generally observed between dominant environmental factors and deposition fluxes, with specific optimal value ranges favoring particulate matter deposition. The findings provide a scientific basis for evaluating atmospheric particulate matter deposition processes, enhancing ecological functions, and improving environmental management in coastal wetlands.