资源环境科技发展态势分析平台

Two short-term field campaigns were conducted to confirm the arrival of African dust onto the Yucatan Peninsula in July 2017 and July 2018 at the city of Merida atmospheric observatory (20.98° N 89.64° W). Aerosol particles were monitored at the ground level by different on-line and off-line sensors. Several PM_2.5 and PM₁₀ peaks were observed during both sampling periods, with a relative increase in the PM levels ranging between 200 % and 500 % with respect to the normal background. Given that these peaks were found to highly correlate with super micron particles and chemical elements typically found in mineral dust particles, such as Al, Fe, Si, and K, they are linked with African dust. This conclusion is supported by combining back trajectories with vertical profiles from radiosondes, reanalysis, and satellite images to show that the origin of the air masses arriving at Merida was the Saharan Air Layer (SAL). The good agreement found between the measured PM>sub>10 concentrations and the estimated dust mixing ratio content from MERRA-2 (Version 2 of the Modern-Era Retrospective analysis for Research and Applications) corroborates the conclusion that the degradation of the local (and likely regional) air quality in Merida is a result of the arrival of African dust.