Freeway air pollution travels farther in early morning(Bettina Boxall, Los Angeles Times, Apr. 17, 2013)
Also discussed here: Air board will start monitoring pollution next to SoCal freeway(Tony Barboza, Los Angeles Times, Aug. 25, 2013)
And here: EPA’s Remarkable New Air Pollution Monitors (I’m like a Kid in a Candy Store(Gretchen Goldman, Union of Concerned Scientists, Aug. 29, 2013)
And here: A wide area of air pollutant impact downwind of a freeway during pre-sunrise hour(Abstract, · Shishan Hu, Scott Fruin, Kathleen Kozawa, Steve Mara, Suzanne E. Paulson, Arthur M. Wine, Atmospheric Environment, May 2009)
Today we review news that the Environmental Protection Agency will be implementing a program to monitor air quality within 160 ft of major roadways for the 100 largest cities in the US. This comes as more and more research indicate both the health risks produced by exposure to those who live near roadways (even at sunrise before peak rush hour traffic) and the extent to which pollution from the highways drift downstream (1.2 km).
"We have known about the adverse health impacts of living near freeways for almost 20 years but don't routinely monitor air quality there,"
“Under EPA rules to be phased in over three years, starting in January, the largest metropolitan areas must put four monitors within about 160 feet of major roadways to measure nitrogen oxides, fine particulates and carbon monoxide. Smaller areas will be required to have between one and three monitors.”
“Under EPA requirements, monitors will be installed at four sites, providing data about what the 1 million Southern Californians who live within 300 feet of a freeway are breathing…Similar steps will occur in more than 100 big cities across the country.”
“It’s clear heavily trafficked roadways have a large impact on downwind populations, and a similar situation likely happens around the world in the early morning hours…The particles tend to end up indoors, so a lot of people are being exposed inside their homes and schools.”
“downwind UFP [ultrafine particle] concentrations as high as ∼40 000 cm−3 extended at least 1200 m from the freeway, and did not reach background levels (∼15 000 cm−3) until a distance of about 2600 m….UFP concentrations were also elevated over background levels up to 600 m upwind of the freeway.”
“wide air pollutant impact area downwind of a major roadway prior to sunrise has important exposure assessment implications since it demonstrates extensive roadway impacts on residential areas during pre-sunrise hours, when most people are at home.”