A concrete block manufacturer operates a natural gas-fired furnace-type curing kiln (rated at 20 Mbtu/hr) and consumes 820, 000, 000 cubic meters of fuel annually.  Being similar to a concrete batch plant, sand, aggregate and cement are hauled to the site, stockpiled and then transferred to elevated storage bins and silos.  Records indicate that 1, 050 tons of aggregate, 760 tons of sand and 1, 850 tons of cement are purchased each year.  Considering only the natural gas fuel combustion and the transfer of materials to storage bins or silos, estimate the total annual particulate matter (PM) emissions coming from this manufacturer and the annual PM emissions for each source.  Identify the source that emits the greatest amount of PM.  Use the most current AP-42 for your emissions factors.