Cooling fans and dust
In the past, one aspect of my job, was the maintenance of about 150 Danfoss frequency drives which have cooling fans, they had external replaceable air filters. Some charge controllers and inverters which employ cooling fans run often, ingesting airborne dust and pollen etcetera, in the case of my inverter charger, the fans run almost constantly, tropical climate, within a few weeks there was a fine brown coat of dust in the intake grill. My solution was to use automotive air conditioning cabin filters over the intakes, was curious what other ideas may be employed, this dust can't be good for the electronics.
1500W, 6× Schutten 250W Poly panels , Schneider MPPT 60 150 CC, Schneider SW 2524 inverter, 400Ah LFP 24V nominal battery bank