Temporal variation of the PM2.5/PM10 ratio and its association with meteorological factors in a South American megacity: Metropolitan Area of Lima-Callao, Peru

• Published in: Environmental monitoring and assessment 2024-05, Vol.196 (5), p.452-452, Article 452
• Main Authors: Espinoza-Guillen, José Abel, Alderete-Malpartida, Marleni Beatriz, Navarro-Abarca, Ursula Fiorela, Gómez-Muñoz, Hanns Kevin
• Format: Article
• Language: English
• Subjects: Air pollution; Air quality; Air temperature; Anthropogenic factors; Atmospheric Protection/Air Quality Control/Air Pollution; Bivariate analysis; Correlation analysis; Earth and Environmental Science; Ecology; Ecotoxicology; Emissions; Environment; Environmental Management; Megacities; Meteorological parameters; Metropolitan areas; Monitoring/Environmental Analysis; Outdoor air quality; Particulate emissions; Particulate matter; Pollution sources; Relative humidity; Resuspension; Suspended particulate matter; Temporal variability; Temporal variations; Trends; Variability; Wind speed
• ISSN: 0167-6369; 1573-2959
• DOI: 10.1007/s10661-024-12611-4

The Metropolitan Area of Lima-Callao (MALC) is a South American megacity that has suffered a serious deterioration in air quality due to high levels of particulate matter (PM 2.5 and PM 10 ). Studies on the behavior of the PM 2.5 /PM 10 ratio and its temporal variability in relation to meteorological parameters are still very limited. The objective of this study was to analyze the temporal trends of the PM 2.5 /PM 10 ratio, its temporal variability, and its association with meteorological variables over a period of 5 years (2015–2019). For this, the Theil-Sen estimator, bivariate polar plots, and correlation analysis were used. The regions of highest mean concentrations of PM 2.5 and PM 10 were identified at eastern Lima (ATE station—41.2 µg/m 3 ) and southern Lima (VMT station—126.7 µg/m 3 ), respectively. The lowest concentrations were recorded in downtown Lima (CDM station—16.8 µg/m 3 and 34.0 µg/m 3 , respectively). The highest average PM 2.5 /PM 10 ratio was found at the CDM station (0.55) and the lowest at the VMT station (0.27), indicating a predominance of emissions from the vehicular fleet within central Lima and a greater emission of coarse particles by resuspension in southern Lima. The temporal progression of the ratio of PM 2.5 /PM 10 showed positive and highly significant trends in northern and central Lima with values of 0.03 and 0.1 units of PM 2.5 /PM 10 per year, respectively. In the southern region of Lima, the trend was also significant, showcasing a value of 0.02 units of PM 2.5 /PM 10 per year. At the hourly and monthly level, the PM 2.5 /PM 10 ratio presented a negative and significant correlation with wind speed and air temperature, and a positive and significant correlation with relative humidity. These findings offer insights into identifying the sources of PM pollution and are useful for implementing regulations to reduce air emissions considering both anthropogenic sources and meteorological dispersion patterns.