Black carbon testing finds high levels
When the City Council passed an ordinance in early April to reduce emissions from construction equipment working on city jobs, it touched on a larger problem: harmful amounts of diesel exhaust in Chicago's air.
Residents of several neighborhoods are most likely exposed to diesel emissions at levels several times higher than the national average for urban areas, testing by the Chicago News Cooperative shows.
The tests were conducted with a Micro Aethalometer made by Magee Scientific, a tool frequently used by public health groups and academics to quantify diesel exhaust. Four environmental and public health scientists helped interpret the results. The testing does not meet the rigorous standard of peer-reviewed scientific literature, but it does indicate that even years after the decline of heavy industry in Chicago, air quality in many neighborhoods remains a concern.
In nearly 100 hours of spot testing in early April - near dense residential areas, schools and parks in both working-class and wealthier neighborhoods - tests revealed elevated levels of black carbon. Testing for black carbon is a common way to determine levels of diesel exhaust, which is linked to higher risks of cancer, heart disease and lung disease and is also known to worsen allergies and asthma.
Experts said the tests indicated troubling levels of diesel pollution in Little Village, Lincoln Park, Ukrainian Village, Wicker Park, Pilsen and other areas.
"Some of the results may be of concern for potential health effects in exposed individuals, particularly in sensitive subpopulations such as children and elderly," said Serap Erdal, an associate professor of environmental and occupational health sciences at the University of Illinois at Chicago.
Diesel emissions contain a relatively high proportion of very fine particles, scientists say, which are especially harmful because they can penetrate deeply into the lungs and even into the bloodstream. The emissions also contain toxic metals and carcinogenic hydrocarbons.
"There's suspicion that diesel is a lot more toxic than other types of particulate matter because of the things it's enriched with," said Scott Fruin, an assistant research professor of environmental health at the University of Southern California.
The Clean Air Task Force, a public health advocacy group, estimates that in the Chicago metropolitan area, particulates from diesel emissions cause 723 premature deaths, 1,125 heart attacks and 28,201 asthma attacks each year.
Cheryl Newton, director of the Region 5 Air and Radiation Division of the federal Environmental Protection Agency, said the Chicago area as a whole met federal standards for particulate matter.
Major American cities generally have background levels of one to three micrograms of black carbon per cubic meter. There are no federal standards specifically for diesel emissions. But California, which has taken a strict approach to diesel pollution, has an eight-hour workday health standard for diesel particulate that converts to two to three micrograms per cubic meter of black carbon.
Spot testing around Chicago showed background levels of one to two micrograms of black carbon per cubic meter. But near trucking routes and rail yards in several locations, the levels were significantly higher.
Benito Juarez Community Academy in Pilsen sits at the corner of two major trucking routes: Ashland Avenue and Cermak Avenue. On a Wednesday afternoon at the bus stop near the school's entrance, average black carbon levels were 7.2 micrograms per cubic meter.
In Ukrainian Village near the intersection of Western Avenue and Grand Avenue, just east of Smith Park, the average black carbon level was 4.8 micrograms per cubic meter. In Little Village, in front of homes on 31st Street west of Kedzie Avenue, the level on a late weekday morning was 20.5 micrograms.
Upscale areas were no better. Testing in Lincoln Park showed an average 23 micrograms between Webster Place and Janssen Avenue, a residential street. Three separate residential and commercial strips in trendy Wicker Park yielded an average of 6.7 micrograms per cubic meter.
The City Council ordinance passed this month aims to reduce diesel emissions from construction equipment by requiring contractors on city jobs to use cleaner fuel and better pollution-control technology. But city officials have little power to regulate the trucks and locomotives that account for most of the city's diesel emissions.
Scientists say that while construction vehicles contribute significantly to overall diesel emissions in an area, their effect is usually temporary. Disease risk typically is linked to long-term exposure, so rail yards and truck routes most likely pose a greater risk.
Locomotive engines may cause particular concern. Ms. Erdal pointed to her own work as well as published studies indicating that the particulate matter from locomotives is typically smaller and has higher concentrations of some carcinogens, making it more dangerous than exhaust from trucks.
In Pilsen, an elevated rail yard connected to the 16th Street viaduct is directly above the dense working-class, immigrant neighborhood. Average black carbon levels were 10.2 micrograms per cubic meter one night as yellow locomotives emitted hissing plumes of bluish exhaust.
Brian Urbaszewski, director of environmental health programs for the Respiratory Health Association of Metropolitan Chicago, said Pilsen residents were also inhaling particulate matter from the nearby coal-fired power plant, "getting a one-two punch."