Some are big, some are small, some are busy and some may be quiet — none of those factors seem to matter much when it comes to how likely an airport is to spread disease. In a new study, researchers checked out the nation’s 40 largest airports to determine where you might want to make extra sure to wash your hands.

Researchers at the Massachusetts Institute of Technology’s Civil and Environmental Engineering department factored in passengers’ travel patterns, the airports’ geographic locations, interactions between airports and passenger waiting times for their study on which cities are most likely to spread a disease in the event of an outbreak in the cities they serve. The results were published recently in the journal PLoS ONE.

CNN notes that one of the biggest surprises in the rankings was that how busy or large the airport was didn’t necessarily mean it was high up on the list of germy places.

For example, New York’s John F. Kennedy International Airport and Los Angeles International Airport were first and second on the list — which makes sense, as the cities they serve are big and there’s a high volume of traffic there daily. But then coming in third was Honolulu International Airport, even though it carries only 30% as much traffic as Kennedy. That’s because Honolulu is in the Pacific Ocean and has connections to large, distant hubs, say researchers.

Meanwhile, Hartsfield-Jackson Atlanta International Airport has the most flights, but it only ranked eighth on the list of potential disease spreaders, and big Boston Logan International Airport was down the list at 15.

After JFK, LAX and Honolulu comes San Francisco International Airport, Newark Liberty International Airport, Chicago O’Hare International Airport, and Washington Dulles International Airport, Atlanta, Miami International Airport and Dallas/Fort Worth International Airport.

Researchers say this could help figure out ways to contain infections in a specific area and help public health officials make decisions about treatment and vaccines in the early days of an outbreak. If they can figure out ways to stop diseases from spreading beyond where they start, some infections might never become full pandemics.

You can still get mad at the sneezing guy, actually, just know that it might not be all his fault — it could just be the airport.

Researchers list top 10 airports for spreading disease [CNN]

Want more consumer news? Visit our parent organization, Consumer Reports, for the latest on scams, recalls, and other consumer issues.