The case of “public congregation vs. COVID-19 PPE pollution”: Evidence, lessons, and recommendations from the annual pilgrimage to the Catholic Holy Site in Mexico City, Mexico

Pollution from personal protective equipment (PPE), particularly face masks, has surfaced in the marine and terrestrial environments globally since the COVID-19 outbreak due to improper disposal practices and inadequate waste management, raising widespread alarm and attention. Our understanding of the prevalence and distribution of PPE in highly populated metropolitan areas is still emerging, and studies focusing specifically on developing countries in Latin America remain sparse. This study attempted to “kill two birds with one stone” by (1) addressing this knowledge gap by analyzing the degree of improper dispensing of PPE in Mexico City (Mexico) and (2) investigating the impact of massive public congregations on PPE contamination during the yearly pilgrimage to the Villa de Guadalupe on December 12th. Our survey findings revealed 731 PPE items within a 6-kilometer radius between December 5 and December 12, 2021, with daily densities ranging from 4.1 × 10(−3)–13.9 × 10(−3) PPE items m(−2). Face masks were the most disposed type of PPE (94%), with gloves and face shields accounting for just 6% of the total. The PPE disposal more than doubled as the pilgrim day approached, with an estimated disposal rate ranging from 151.52 to 506.06 items day(−1), substantiating the surge in the disposal of used PPE to large public congregations that filled the surroundings during the pilgrimage. The observed average PPE density of 7.8 × 10(−3) items m(−2) was higher than in the metropolitan environments of Canada, Ghana, and Turkey. To our knowledge, this first study describes information showing the need to pay attention to the major impact of public events and mobility on COVID-19 PPE pollution, as well as emphasizes the necessity for adequate management facilities in improving PPE disposal.