Río Abajo is a corregimiento in the urban area of Panama City that grew in the early decades of the twentieth century, when West Indian Canal workers settled around the river that gives it its name. Over time the main road was widened and neighborhoods, schools and service facilities were added. Many wooden West Indian style houses are being replaced by more modern buildings.
That renewal leaves equipment from very different periods a few blocks apart: a house with an old installation, a newly finished building and a shop with its own system. Nothing is assumed: each property is reviewed on its own. In a recent building, the way the network was left after construction is checked. The area is about 4 km by road from the Climatiza office, in an approximate calculation.
Data point: A modeling study by Waring and Siegel (2008) estimated that filters in commercial systems collect a median of 130 g/m² per month, compared with 2.97 in residential ones. It is an estimate, which is why the actual case is inspected.