New urban air pollution problem: Dog poop

Bacteria from dog fecal material may constitute the dominant source of airborne bacteria in Cleveland’s and Detroit’s wintertime air, says a new University of Colorado Boulder study.

The study’s media release says,

Scientists already knew that bacteria exist in the atmosphere and that these bacteria can have detrimental effects on human health, triggering allergic asthma and seasonal allergies, [University of Colorado-Boulder researcher Noah Fierer] said. But it is only in recent years that researchers have realized that there is an incredible diversity of bacteriaresiding in the air, he said.

“There is a real knowledge gap,” said Fierer. “We are just starting to realize this uncharted microbial diversity in the air — a place where you wouldn’t exactly expect microbes to be living.”

To gain further understanding of just what microbes are circulating in urban environments, the team analyzed the local atmosphere in the summer and winter at four locations in the Great Lakes region of the U.S. Three of the locations — Chicago, Cleveland and Detroit — are major cities with populations of greater than 2 million, and one location, Mayville, Wis., is a small town with a population of less than 6,000.

The team used nearly 100 air samples collected as part of a previous study conducted by Colorado State University. The CSU experiment investigated the impact of biomass burning and involved studying the impacts of residential wood burning and prescribed fires on airborne fine particle concentrations in the midwestern United States.

“What we’ve been looking at are the numbers and the types of bacteria in the atmosphere,” Fierer said. “We breathe in bacteria every minute we are outside, and some of these bugs may have potential health implications.”

The researchers analyzed the bacteria’s DNA in the collected air samples and compared the bacteria they found against a database of bacteria from known sources such as leaf surfaces, soil, and human, cow and dog feces. They discovered that the bacterial communities in the air were surprisingly diverse and also that, in two of the four locations, dog feces were a greater than expected source of bacteria in the atmosphere in the winter.

In the summer, airborne bacteria come from many sources including soil, dust, leafsurfaces, lakes and oceans, Bowers said. But in the winter, as leaves drop and snow covers the ground, the influence that these environments have as sources also goes down. It is during this season that the airborne communities appeared to be more influenced by dog feces than the other sources tested in the experiment, he said.

“As best as we can tell, dog feces are the only explanation for these results,” Fierer said. “But we do need to do more research.”

I wonder how many of EPA’s studies of air quality and health have considered dog poop particulate as a confounding risk factor?

4 thoughts on “New urban air pollution problem: Dog poop”

  1. Allen,
    In the winter many sources are reduced since they are covered with snow. Most birds migrate south, and many other critters hibernate. I doubt there are many deer in these densely populated urban environments. But the dogs stay and they still need to poop. So I can easily see how they can become the dominant source. I just wonder if this is due mainly to strays or people that don’t pick up after their pets. I always carry bags with me when I walk my dogs, but I see an alarming number of people that don’t. Shame on all of you that don’t pick up your pet’s waste when you walk them!

  2. This study is indeed a load of…poop. How did the dog portion go from ‘greater than expected’ in the body of the text to ‘the dominant source’ in the tag line? Plus they’re leaving out ‘natural poop’: deer, racoon, birds, etc. These are much more prevelant than dog.

  3. This condition has been observed in Mexico City. There is a population of dogs and humans that live in the dumpos on the outskirts of the city. They burn whatever they can find ot warm themselves, and to cook. The smoke, and everything else originating there is carried by the air currents into the city where is falls on any surface available.

    WARNING: It’s a good idea not to eat from the open vendors there.

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