Temporal patterns and relationship between meteorological variables and PM2.5 and PM10 particulate matter at two monitoring stations in Metropolitan Lima

Abstract

Fine particulate matter pollution is a critical environmental challenge in urban metropolises, where its concentration varies with temporal and microclimatic factors. In this study, we evaluated the association between meteorological variables and PM_2.5 and PM₁₀ at the Santa Anita and Campo de Marte (Jesús María) stations in Lima from 2015 to 2023. Hourly data from SENAMHI were used at annual, monthly, and hourly scales and analyzed using descriptive statistics, Student’s t-test, time series analysis, wind roses, and Spearman's correlation. Santa Anita consistently recorded higher levels, with PM₁₀ averages of 84.99 μg/m³ in 2019, 77.77 μg/m³ in September, and a diurnal peak of 82.03 μg/m³ (14:00 h). In contrast, Campo de Marte presented lower concentrations and a continuous reduction in PM₁₀ (from 40.80 μg/m³ in 2015 to 14.58 μg/m³ in 2023). Significant microenvironmental differences were evidenced: higher average ventilation and precipitation in Santa Anita, and higher relative humidity in Campo de Marte. At the monthly scale, an inverse relationship between temperature and PM_2.5 was evident (ρ = -0.63), and at the annual scale, a positive association between humidity and PM₁₀ was observed (ρ = 0.50). The study concluded that the temporal behavior of particulate matter depends on the interaction among time scale, meteorology, and land use, with vegetative cover buffering pollution levels, whereas industry, heavy diesel traffic, and exposed soil favor its accumulation and resuspension.