Metal Enrichment in Settleable Particulate Matter Associated with Air Pollution in the Andean City of Ecuador

Air pollution is one of the major environmental challenges worldwide. Settleable particulate matter (SPM), related to this environmental problem, contains metals capable of producing negative effects on human health (e.g., cardiovascular and respiratory illness). For this study, continuous monitoring was carried in the urban city of Loja (Ecuador), where 10 points were distributed based on different land uses. Samples were collected on a monthly basis using a passive method, by means of samplers built based on the 502 Method. The gravimetric method was then used in the laboratory to determine the concentration of SPM. The inductively coupled plasma–optical emission spectroscopy (ICP-OES) technique was used to identify the presence of metals as such as Copper (Cu), Lead (Pb), Cobalt (Co), Cadmium (Cd), Chromium (Cr), Silver (Ag), Arsenic (As), and Mercury (Hg) in SPM. The results obtained showed that SPM and As differed significantly between land uses, but most metals showed significant differences in relation to temporal changes. Although 90% of the sampling points show SPM concentrations within the limits established by environmental regulations, some of the points exceed the World Health Organization (WHO) limit of 0.5 mg/cm2. Finally, the temporal changes in more metals were clearly observed, probably because of increased combustion processes (vehicular traffic), with a higher percentage of metals clearly observed during the April and August months. Furthermore, the highest levels of vegetation burning in Loja province, including the surroundings of the city of Loja, occurred in August. This analysis provides essential data to guide environmental monitoring and air quality management strategies, aiming to reduce health risks from long-term exposure to metal-enriched particulate matter.