Narrative:

The APU was on the MEL. We started engine #1 at the gate with an air-start machine. We pushed back and cross-bleed started the 2nd engine. As we began the taxi; while still on the ramp; the 'a' flight attendant called us and said there was a bad odor in the cabin and many passengers were complaining. I told her it was probably due to the air start and or cross-bleed start and it would probably clear up. I told here to call me back in about 5 minutes and tell me if it was any better. She called back about 5 minutes later and said it was no better; perhaps worse. We called ground control and asked them if we could pull into the cargo ramp; and we did. I turned the airplane into the wind; so as to eliminate any engine exhaust from blowing back into the airplane. I bumped the power up slightly (25% N1) above idle to help with the air flow. I selected 'hi' flow for our packs and we sat there for a few more minutes to see if it got better. I sent the first officer back to see what he thought. He came back a few minutes later and said he certainly smelled it and it smelled like a faint electrical smell to him. Passengers and flight attendants reported it as a burning plastic or musty smell. I too; thought it smelled musty. After a few minutes; we all decided it wouldn't be a good idea to fly this airplane. We returned to the gate and I radioed for a customer service and maintenance supervisor to meet the airplane. They did and all agreed there was a bad; unidentifiable odor in the airplane. One female passenger complained of burning eyes. We transferred to another airplane and completed our flight.how about an air quality monitor in the cabin? This is costing the airlines millions and; in some cases; causing harm to crew members and passengers. Most of these odor problems are probably nothing; but how do we know? We have to keep safety in mind. If there's any doubt; we don't go! There are lots of odors on an airplane. Most of which are probably harmless. We have carbon monoxide detectors in our homes. Can't we get something to monitor the air in our cabins? It would probably benefit the airlines to do this; we would probably have a lot less 'toxic fume' incidents if the crew knew that what they smelled wasn't going to harm them!

Related reports:

Google
 

Original NASA ASRS Text

Title: An A320 with an inoperative APU developed a dirty socks odor after a cross bleed engine start; so the aircraft returned to the gate where it was removed from service. Captain suggested that adding air quality monitor devices would help.

Narrative: The APU was on the MEL. We started engine #1 at the gate with an air-start machine. We pushed back and cross-bleed started the 2nd engine. As we began the taxi; while still on the ramp; the 'A' Flight Attendant called us and said there was a bad odor in the cabin and many passengers were complaining. I told her it was probably due to the air start and or cross-bleed start and it would probably clear up. I told here to call me back in about 5 minutes and tell me if it was any better. She called back about 5 minutes later and said it was no better; perhaps worse. We called Ground Control and asked them if we could pull into the cargo ramp; and we did. I turned the airplane into the wind; so as to eliminate any engine exhaust from blowing back into the airplane. I bumped the power up slightly (25% N1) above idle to help with the air flow. I selected 'HI' flow for our packs and we sat there for a few more minutes to see if it got better. I sent the First Officer back to see what he thought. He came back a few minutes later and said he certainly smelled it and it smelled like a faint electrical smell to him. Passengers and flight attendants reported it as a burning plastic or musty smell. I too; thought it smelled musty. After a few minutes; we all decided it wouldn't be a good idea to fly this airplane. We returned to the gate and I radioed for a Customer Service and Maintenance Supervisor to meet the airplane. They did and all agreed there was a bad; unidentifiable odor in the airplane. One female passenger complained of burning eyes. We transferred to another airplane and completed our flight.How about an air quality monitor in the cabin? This is costing the airlines millions and; in some cases; causing harm to crew members and passengers. Most of these odor problems are probably nothing; but how do we know? We have to keep safety in mind. If there's any doubt; we don't go! There are lots of odors on an airplane. Most of which are probably harmless. We have carbon monoxide detectors in our homes. Can't we get something to monitor the air in our cabins? It would probably benefit the airlines to do this; we would probably have a lot less 'Toxic Fume' incidents if the crew knew that what they smelled wasn't going to harm them!

Data retrieved from NASA's ASRS site as of April 2012 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.