Last Update: July 25, 2015
Children who live close to major transport hubs are more at risk of dying of cancer, a study says. University of Birmingham researchers found those living within 500 metres of a bus station were six times more likely to die of cancer. ... Researchers analysed details about the deaths of 22,500 children between 1955 and 1980 from cancers such as leukaemia, lymphoma, and brain and spinal cancers, the Journal of Epidemiology and Community Health reported. They found carbon monoxide and 1,3-butadience, both of which are produced by vehicle exhausts and particularly diesel engines, were the major cause of the increased risk. But other chemicals, including nitrogen oxides and dioxins, were also cited in the report. They calculated there could be a 12-fold increase in risk for children living near bus stations and emission hotspots. See: Child cancer 'exhaust fume risk', 10 August 2005, BBC.CO.UK http://news.bbc.co.uk/2/hi/health/4138684.stm
Research by the California Air Resources Board (CARB)
The California Air Resources Board has an extensive information area on its website. See: Health Effects of Air Pollution, California Air Resources Board, http://www.arb.ca.gov/research/health/health.htm Some portions of their site is summarized below.
Health effects of Diesel
Because some areas of California suffer from extreme exposure to diesel exhaust -- such as the trucking corridor between the Port of Los Angeles and the rail terminal -- CARB has sponsored lots of research into Diesel and mitigating its effects. See: Diesel & Health Research, California Air Resources Board, http://www.arb.ca.gov/research/diesel/diesel-health.htm
Diesel engines emit a complex mixture of air pollutants, composed of gaseous and solid material. The visible emissions in diesel exhaust are known as particulate matter or PM. In 1998, California identified diesel exhaust particulate matter (PM) as a toxic air contaminant based on its potential to cause cancer, premature death, and other health problems. Diesel engines also contribute to California's fine particulate matter (PM2.5) air quality problems. Those most vulnerable are children whose lungs are still developing and the elderly who may have other serious health problems.
Diesel particulate matter, when breathed in, is transferred into the bloodstream and from there can enter cell tissue. See: Diesel exhaust exposure, CARB, http://www.arb.ca.gov/research/diesel/exposure.pdf This causes a variety of illnesses.
Asthma & Air Pollution
The California Air Resources Board has sponsored a lot of research into the connection between air pollution, such as diesel exhaust, and Asthma. See: Asthma and Air Pollution, California Air Resources Board, http://www.arb.ca.gov/research/asthma/asthma.htm
Asthma is a serious chronic lung disease that appears to be on the rise in California, the United States and many other countries around the world. The prevalence of asthma in the U.S. has increased by more than 75% since 1980; children and certain racial groups, especially African Americans, have experienced relatively greater increases in asthma prevalence.
Air pollution plays a well-documented role in asthma attacks, however, the role air pollution plays in initiating asthma is still under investigation and may involve a very complex set of interactions between indoor and outdoor environmental conditions and genetic susceptibility.
Children's School Bus Exposure Study
Study (See:. Children's School Bus Exposure Study, California Air Resources Board, http://www.arb.ca.gov/research/schoolbus/schoolbus.htm) was conducted to characterize the range of children's exposures to diesel vehicle-related pollutants and other vehicle pollutants during their commutes to school by school buses. It was the most comprehensive school bus exposure study ever conducted. Researchers at the University of California's Riverside and Los Angeles campuses, measured pollutant concentrations inside five conventional diesel school buses while driving actual school bus routes in Los Angeles. For comparison, a diesel bus equipped with a particulate trap and a bus powered by natural gas were also included.
Buses were outfitted with dual sets of real-time instruments, which allowed front versus back and inside versus outside comparisons. The researchers measured multiple diesel vehicle-related pollutants, including black carbon and particle-bound PAHs, as well as many other exhaust pollutants. A tracer gas was used to determine the bus's own contributions to on-board concentrations. The study measured exposures inside the buses and did not include tail-pipe emissions tests.
Measurements indicated that for some buses, significantly higher exposures of vehicle-related pollutants occurred during the bus commutes than roadway pollutant concentrations alone would indicate. The high commute concentrations were a function of several influences:
- the high concentrations of pollutants already present on roadways, especially if traffic was heavy;
- the direct influence of other vehicles being followed; and
- the contribution of the bus’s own emissions. The extent of a bus’s own contribution to these high concentrations appeared to be highest when windows were closed for the older diesel buses, but bus-to-bus variability was high.
Huntington Park Asthma Study
An epidemiological study (See: Huntington Park Asthma Study, California Air Resources Board, http://www.arb.ca.gov/research/delfino/delfino.htm) of the acute respiratory health effects of air pollution, particularly air toxics, on children with asthma. Twenty-six asthmatic Hispanic school children residing in Eastern Los Angeles participated in the study during the winter of 1999-2000. The study was co-sponsored by the California Air Resources Board and the South Coast Air Quality Management District and conducted by investigators at the University of California, Irvine.
- The information gathered in this study provides insight regarding the measurement methods needed to assess personal Volatile Organic Compound (VOC) exposures and doses in children.
- The association between exposure to VOCs and asthma symptoms is largely unknown. This is one of the first epidemiological studies to evaluate the association between exposure to VOCs and other criteria air pollutants and acute health effects in asthmatic children.
FACES (Fresno Asthmatic Children's Environment Study)
The Fresno Asthmatic Children's Environment Study, FACES (Fresno Asthmatic Children's Environment Study), California Air Resources Board, http://www.arb.ca.gov/research/faces/faces.htm, which began in 2000, is a large epidemiological study of the effects of air pollution on children with asthma. About 250 asthmatic children who reside in the Fresno area of the Central Valley of California will be enrolled in the study. The overall goal of this study is to determine the effects of different components of particulate matter (PM), in combination with other ambient air pollutants, on the natural history of asthma in young children. The study is sponsored by the California Air Resources Board and conducted by investigators at the University of California, Berkeley. An overview of the Fresno Asthmatic Children's Environment Study is available here and the Fresno Asthmatic Children's Environment Study Fact Sheet is here.
- The information provided by the study will help the Air Resources Board (ARB) protect public health. The ARB sets California's ambient air quality standards to protect people who are most sensitive to air pollution.
- Children may be more strongly affected by air pollution because their lungs and bodies are still developing. Understanding the effects of air pollution on children with asthma is essential for setting health standards protective of sensitive populations.
ARB CNG and Diesel Transit Bus Emissions Research
The Air Resources Board (ARB) has led a multi-agency research effort to collect emissions data from late-model heavy-duty transit buses in five different configurations. The objectives of the study were 1) to assess driving cycle effects, 2) to evaluate toxicity between new and "clean" heavy duty engine technologies in use in California, and 3) to investigate total PM and ultrafine particle emissions. See: ARB CNG and Diesel Transit Bus Emissions Research, California Air Resources Board, http://www.7gen.com/website/diesel/carb-cng-and-diesel-transit-bus-emissions-research/1423
Chassis dynamometer testing was conducted at ARB's Heavy-duty Emissions Testing Laboratory (HDETL) in Los Angeles. The impetus behind this work was to compare the emissions from transit buses powered by similar engines and fueled by ARCO (a BP company) Low Sulfur Emission Control Diesel (ECD-1) and compressed natural gas (CNG). Follow-on work focused on the assessment of aftertreatment control for CNG applications. Five vehicle configurations were investigated: 1) a CNG bus equipped with a 2000 DDC Series 50G engine certified for operation without an oxidation catalyst, 2) the same CNG bus retrofitted with an OEM oxidation catalyst, 3) a diesel bus equipped with a 1998 DDC Series 50 engine and a catalyzed muffler, 4) the same diesel vehicle retrofitted with a Johnson Matthey Continuously Regenerating Technology (CRT) diesel particulate filter (DPF) in place of the muffler, and 5) a CNG bus equipped with a 2001 Cummins Westport C Gas Plus engine and OEM-equipped oxidation catalyst.
The duty cycles were: 1) idle operation, 2) a 55 mph steady-state (SS) cruise condition, 3) the Central Business District (CBD) cycle, 4) the Urban Dynamometer Driving Schedule (UDDS), and 5) the New York City Bus Cycle (NYBC). Collection of PM over multiple cycles was performed to ensure sufficient sample mass for subsequent chemical analyses. Information on regulated (NOx, HC's, PM, and CO) and non-regulated (CO2, NO2, gas-phase toxic HC's, carbonyl compounds, polycyclic aromatic hydrocarbons, elements, and elemental and organic carbon) emissions was collected. Size-resolved PM mass and number emission measurements were conducted and extracts from diesel and CNG total PM samples were tested in the Ames mutagenicity bioassay analysis to determine mutagen emission factors.