Small-scale spatial and temporal evolution characteristics of PM2.5 and PM10 concentrationsand the influence of meteorological factors: a case study of Zhenjiang Port, China

The analysis of the small-scale spatial and temporal evolution characteristics of particulate matter (PM), especially Particulate Matter 2.5 (PM _2.5 ) and Particulate Matter 10 (PM ₁₀ ), and the influence of meteorological factors is crucial for understanding the mechanisms of large-scale PM formation and transport, and further to develop precise dust pollution prevention measures. In this study, Zhenjiang Port was analyzed first time, which was based on hourly data of PM _2.5 and PM ₁₀ concentrations from 15 air quality monitoring stations from January 2019 to December 2020. With respect to evolution characteristics of PM _2.5 and PM ₁₀ concentrations within the study area, the results showed that: (1) Daily averages exhibit varying degrees of exceedances, with PM _2.5 exceeding Level 3 standards accounting for 13.68%. (2) Spatially, both PM _2.5 and PM ₁₀ display a pattern of higher concentrations in the western areas and lower concentrations in the eastern areas. (3) Diurnal fluctuations are relatively stable during the day, with peak values occurring around 06:00 in the morning. (4) PM _2.5 has a long retention time in the air with hysteresis. (5) For the relationship of concentration and temperature, it shows positive correlation for below 6°C while negative correlation for above 6°C. (6) For the relationship of concentration and relative humidity, it shows positive correlation for below 80% and above 90%, while negative correlation for at 80–90%. The research findings can provide a theoretical basis for formulating atmospheric pollution prevention and control measures for Zhenjiang Port, while also serving as a reference for studying the evolution mechanisms of PM in Zhenjiang City and even larger-scale regions.