Asthma Symptoms Linked to Soot Particles from Diesel Trucks
17 October 2006
Soot particles from the exhaust of diesel trucks constitute a major contributor to the alarmingly high rates of asthma symptoms among school-aged children in the South Bronx, according to the results of a five-year study by researchers at New York University’s School of Medicine and Robert F. Wagner Graduate School of Public Service.
Over the course of the study, asthma symptoms, particularly wheezing, doubled among elementary school children on high traffic days, as large numbers attend schools in close proximity to busy truck routes because of past land-use decisions.
The South Bronx has among the highest incidences of asthma hospital admissions in New York City, and a recent city survey of asthma in the South Bronx’s Hunts Point district found an asthma prevalence rate in elementary school of 21% to 23%. The South Bronx is surrounded by several major highways, including Interstates 95, 87, 278 and 895. At Hunts Point Market alone, some 12,000 trucks roll in and out daily.
As part of the investigation, the NYU team dispatched a mobile van lab to assess ground-level pollution levels, and they conducted a “Backpack Study” to monitor carbon concentrations taken from air samples collected by commuting students. The findings have shown that high concentrations of air pollution worsen asthma problems among elementary school children in the South Bronx.
The schools in the study were: PS 154, MS 302, CS 152 and MS 201. Ten elementary school children with asthma from each of the four schools were followed for a month. Data on respiratory symptoms, lung function, activity patterns, as well as personal air pollution exposures were collected at the same time.
According to the study, among all of the children the daily average exposure to particulate matter smaller than 2.5 microns (PM2.5) ranged from 20 to 50 micrograms per cubic meter. In addition, the Environmental Protection Agency’s proposed daily limit of 35 micrograms per cubic meter was exceeded on about one-third of the study days. Only about 10% of the total mass of tiny particles was diesel soot, but it was this portion that was most closely related to children’s adverse health effects.
Particles smaller than 2.5 microns have been mostly closely linked to lung and heart disease. The EPA has regulated PM2.5 since 1997, limiting each person’s average exposure per year to no more than 15 micrograms per cubic meter.
Other studies have shown that people who live near highways have a higher incidence of asthma. But researchers had not measured levels of traffic air pollutants to which individuals were being exposed.
We went in and actually measured personal exposures to traffic pollution, which had not been done before. Our results confirm that diesel soot particles in air pollution are causing exacerbations of asthma in children.
—George Thurston, Sc.D., Associate Professor of Environmental Medicine at NYU School of Medicine
The major type of air pollutant that was associated with symptoms of asthma was elemental carbon. This type of carbon, called black soot, is found in diesel exhaust and is a component of particulate matter in pollution that is smaller than 2.5 microns. This type of carbon has been cited as a causal agent in asthma in a number of other controlled-exposure studies in the laboratory.
Obviously! Perhaps, now that <15ppm ULSD is in the system, this might decrease a bit. Tier2Bin5 diesel engines will likelwise help decrease pollution that is contributing to respitory disease. However, they are likey to be 3-4 years off (2009-2010). Until then, the "no idling" law (for all vehicles) should be enforced.
Posted by: allen_Z | 17 October 2006 at 06:43 AM
Obviously! Perhaps, now that <15ppm ULSD is in the system, this might decrease a bit. Tier2Bin5 diesel engines will likelwise help decrease pollution that is contributing to respitory disease. However, they are likey to be 3-4 years off (2009-2010). Until then, the "no idling" law (for all vehicles) should be enforced.
Posted by: allen_Z | 17 October 2006 at 06:43 AM
Soot is also a contributor to global warming. However, the net effect of these new standards are not clear since sulfur acts as a heat reflectant.
Posted by: t | 17 October 2006 at 07:01 AM
T:
Plants biomass growth rate is limited by availability of soil nitrogen (in ocean it is iron), precipitated from the atmosphere. By reducing emission of NOx from gasoline and currently diesel engines, we substantially decreasing transportation-derived antropogenic carbon sink, thus increasing Global Warming effect.
As usual, it is a matter of priorities: choke themselves or save the planet (dramatization).
Posted by: Andrey | 17 October 2006 at 08:13 AM
The classrooms need to have air filters installed ASAP. Particulate traps need to be installed on all diesels ASAP. Trucks need to be routed away from schools ASAP. The lack of study and resulting inaction speaks volumes about our inability to see the forest for the trees. Next, let's ban transfats and tobacco.
Posted by: JC | 17 October 2006 at 08:56 AM
This is news?
Posted by: pizmo | 17 October 2006 at 09:37 AM
Just another bad secondary effect from burning so much liquid fossil fuel.
Burning coal is often much worse.
Burning wood in good old fashion stoves and beloved fireplaces is just as bad.
Voluntary forest and open fires is another important source.
You can't keep the children is closed air conditioned rooms all the time.
Resultant acid rain has already destroyed all fishes from many lakes and rivers.
The problem must be solved at the source (s).
Posted by: Harvey D. | 17 October 2006 at 10:23 AM
"Only about 10% of the total mass of tiny particles was diesel soot, but it was this portion that was most closely related to children’s adverse health effects."
I'd like to know how they identify which source a particular particle came from, especially those smaller than 2.5 microns. Afaik, it's virtually impossible to deduce this information. However, results from Europe do suggest a statistical *correlation* between clusters of respiratory disease in susceptible groups (incl. children, senior citizens and the poor) and nearby thoroughfares featuring traffic involving a lot of diesel engines. The combination of sulphur and soot was found to be particularly pernicious. ULSD will not only reduce total PM emissions by mass but also substantially alleviate their severity.
The wall-flow particulate filters that are fast becoming standard issue on European diesel LDVs demonstrably reduce PM emissions from diesel engines by well over 95%. HDV diesel engines typically run closer to full load, which means the exhaust gases are hot enough to use the more fuel-efficient continously regenerating trap (CRT) design instead of a wall-flow filter. Some HDV diesel engines currently under development feature HCCI combustion in part load. This cuts engine-out PM levels by up to 90% during stop-and-go traffic, in which CRTs operate poorly or not at all.
Unfortunately, none of this affects legacy diesel engines. DPF retrofits tend to be less effective, though some types use auxiliary burners to maintain adequate temperature levels without touching the engine control map. Needless to say, this has a negative impact on fuel economy.
Posted by: Rafael Seidl | 17 October 2006 at 12:05 PM
"particulate matter smaller than 2.5 microns (PM2.5) ranged from 20 to 50 micro grams per cubic meter"
I remember reading in another article (I'll have to look it up to reference it) that the small micron particulate matter comes from gasoline engines. Something like 10-30 microns from diesel PM and <5 microns for gas PM. If they're measurements aren't being thrown off some how then that means either the stuff they measured came from a gas engine or the PM from diesels srunk.
Posted by: Jason | 17 October 2006 at 03:02 PM
Jason:
Gasoline engine emits particulates only at massive fuel overrich, which often occurred on full throttle on carbureted engine. For more then 25 years gasoline cars are fuel injected and fuel/air mixture is closely computer controlled in closed loop. Even severely malfunctioning gasoline engine (emitting massive amounts of CO and HC) emits soot only small fraction of time. In that respect gasoline cars present on our roads emit overall negligible amount of soot, especially compared to diesel vehicles.
Posted by: Andrey | 18 October 2006 at 12:04 AM
They had a news story about mercury in fish. Coal fired power plants produce a lot of that, but the administration does nothing.
Posted by: SJC | 18 October 2006 at 08:19 AM
Actually, removing particulates from diesel exhaust is fairly easy thanks to particulate filters that trap and eventually "burn off" the particulates (they've been around since the early 1990's). Indeed, the 45-state legal "BlueTec" system used on the 3.2-liter V-6 turbodiesel engine from Mercedes-Benz has nearly no particulate output becaues of such a filter. Removing the higher NOx exhaust, is another matter....
That does explain why the major railroads are buying EMD SD70M-2, EMD SD70ACe, GE ES44DC and GE ES44AC locomotives on a large scale; these new locomotives use a new generation of turbodiesel prime movers with substantial exhaust emission controls.
Posted by: SactoGuy88 | 19 October 2006 at 07:57 PM
Interesting cause of accelerated asthma in children. I agree with Andrey, some form of air filtration needs to be mandatory in classrooms, expecially in dense built up city schools.
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Posted by: Cheryl Ho | 23 May 2007 at 08:07 PM
Detox has quickly become one of the leading ways that people are getting healthier in their lives. The basic premise for these systems goes way back, with the original form of foot detoxification coming 1600 years ago in a Japanese legend. According to the legend a group of people who had a wide range of ailments made a pilgrimage into the mountains.
Posted by: add adhd | 21 March 2008 at 11:39 AM