Do you ever get a whiff of natural gas smell as you’re walking down DC’s streets? I’ve called 311 and/or Washington Gas before, only to be told it’s fine later on, but the smell persists the following days (along Florida Ave in front of Gallaudet is a good example). Well, a research team headed by Robert Jackson of Duke University recently found that DC has “natural gas leaks everywhere, at concentrations of up to 50 times the normal background levels.”
The research was conducted by driving all of DC’s streets and frequently measuring levels of methane over the two-month study period. The results were shocking. From an article in Science Magazine:
They found thousands of places with air concentrations significantly above the 2 parts per million background level typically found in cities, with some areas as high as 100 ppm.
The researchers also found that the excess gas leaks can lead to problems, especially for those with respiratory issues:
Methane leakage at the levels reported by Jackson’s team isn’t a direct health risk. But it can promote the formation of ground-level ozone, which irritates the lungs and at high levels makes it dangerous for people with respiratory problems to be outside.
Although the methane levels above ground were shockingly high, the methane levels in manholes were even worse, possibly leading to manhole explosions:
Even more disturbing than the thousands of large leaks on the street were the levels of methane in manholes. In some, the researchers found levels as high as 10,000 ppm. Natural gas companies typically consider 4000 ppm to be the threshold for a risk of explosion. D.C. manholes have a tendency to blow up—there are an average of 38 “manhole incidents” per year in the district, according to a report by Stone & Webster Consultants in Boston, including one yesterday on 33rd Street in Georgetown that forced the evacuation of a cupcake shop.
You can read the full article on Jackson’s research in DC here: http://news.sciencemag.org/sciencenow/2013/03/washingtons-exploding-manholes-e.html?ref=hp