MD-11 Captain reported a fumes event during preflight while using an external air cart. After replacing the air cart the fumes were no longer present and the flight departed safely.

Narrative

During preflight; the APU failed 10 minutes after starting. We complied with the QRH and contacted Maintenance. The APU was deferred and an external air cart was connected supplying air to the cabin. A few moments later the FO (First Officer) and I noticed a distinct smell coming from the air outlets. Combined with the odor was an irritation to our nose and throats. We immediately exited the cabin and instructed MX (Maintenance) to disconnect the air cart. After speaking with the duty officer and the MX crew; we agreed that the issue was most likely from the air cart and elected to try a different one. The FO and I discussed our exposure to the fumes and; although initially irritating; we decided that we could continue as long there were no more issues with air quality. After the new air cart was connected; we vented the flight deck and concluded that the fumes were no longer an issue. We continued the preflight and departed. Since the fume event; I have experienced a slight congestion that subsided overnight. The purpose of this report is to document the fume event from the external air cart. This same aircraft diverted the following day due to smoke in the cockpit.Checking the quality of the air from the external air cart. My understanding is that there are filters within the carts that need to be serviced.