Children's Exposures/Health Effects/Diesel Exhaust
| Status: | Completed |
|---|---|
| Conditions: | Asthma, Pulmonary |
| Therapuetic Areas: | Pulmonary / Respiratory Diseases |
| Healthy: | No |
| Age Range: | 6 - 11 |
| Updated: | 4/13/2015 |
| Start Date: | March 2005 |
| End Date: | July 2009 |
| Contact: | Erin Corwin |
| Phone: | 206-543-8087 |
Children's Exposure and Health Effects From Diesel Exhaust Before and After Switch of Schoool Bus Fleets
The contribution of diesel exhaust (DE) to health, especially children's health, is of
tremendous public health interest. DE has been associated with worsening asthma and
allergies, among other important health effects. Reducing DE exposures has become a major
regulatory initiative, and federal, state, and local jurisdictions are investing hundreds of
millions of dollars in retrofitting diesel engines in school buses and other changes to
reach this goal.
The U.S. Environmental Protection Agency's recent regulations require all on-road diesel
vehicles to change to low emission engines and ultra-low-sulfur fuels by 2007 (US EPA '00).
In spring 2003, the U.S. EPA announced a nationwide voluntary school bus retrofit
initiative. In July 2003, the Washington Legislature enacted a statewide "Diesel Solutions"
program that provides 25 million dollars by 2008 to retrofit school diesel buses with
cleaner burning engines and fuels, making it one of the largest and most active voluntary
school bus retrofit program in the country. If risk assessment estimates are accurate, these
changes will have a large public health impact, especially on children who ride school buses
daily. However, no studies to-date have rigorously examined school children's exposure to
diesel exhaust (DE) and its health effects, nor such a significant change in vehicular
pollution control. We propose to seize this opportunity of a large natural experiment taking
place in the Puget Sound area and conduct a study to assess health effects from diesel bus
exhaust before and after the retrofit of diesel bus fleets between 2005 and 2007. The
specific aims of the study are to:
1. Determine whether asthmatic children changing to retrofitted buses with cleaner fuels
and engines have a reduction in sub-clinical and clinical asthma severity.
2. Determine if increased levels of DE exposure lead to an increase in acute clinical and
sub-clinical features of asthma in children.
3. Quantify the levels and changes in particle and toxic gas exposures to DE in 3 groups
of children commuting to school by retrofitted buses or private cars, old diesel buses
to be retrofitted later, and old diesel buses through the study.
Sub-aim 3: Use the time-activity information, personal exposure measurements, and on-bus
monitoring data to construct an exposure model to predict individual exposures to DE for all
subjects.
tremendous public health interest. DE has been associated with worsening asthma and
allergies, among other important health effects. Reducing DE exposures has become a major
regulatory initiative, and federal, state, and local jurisdictions are investing hundreds of
millions of dollars in retrofitting diesel engines in school buses and other changes to
reach this goal.
The U.S. Environmental Protection Agency's recent regulations require all on-road diesel
vehicles to change to low emission engines and ultra-low-sulfur fuels by 2007 (US EPA '00).
In spring 2003, the U.S. EPA announced a nationwide voluntary school bus retrofit
initiative. In July 2003, the Washington Legislature enacted a statewide "Diesel Solutions"
program that provides 25 million dollars by 2008 to retrofit school diesel buses with
cleaner burning engines and fuels, making it one of the largest and most active voluntary
school bus retrofit program in the country. If risk assessment estimates are accurate, these
changes will have a large public health impact, especially on children who ride school buses
daily. However, no studies to-date have rigorously examined school children's exposure to
diesel exhaust (DE) and its health effects, nor such a significant change in vehicular
pollution control. We propose to seize this opportunity of a large natural experiment taking
place in the Puget Sound area and conduct a study to assess health effects from diesel bus
exhaust before and after the retrofit of diesel bus fleets between 2005 and 2007. The
specific aims of the study are to:
1. Determine whether asthmatic children changing to retrofitted buses with cleaner fuels
and engines have a reduction in sub-clinical and clinical asthma severity.
2. Determine if increased levels of DE exposure lead to an increase in acute clinical and
sub-clinical features of asthma in children.
3. Quantify the levels and changes in particle and toxic gas exposures to DE in 3 groups
of children commuting to school by retrofitted buses or private cars, old diesel buses
to be retrofitted later, and old diesel buses through the study.
Sub-aim 3: Use the time-activity information, personal exposure measurements, and on-bus
monitoring data to construct an exposure model to predict individual exposures to DE for all
subjects.
We will recruit 450 subjects ranging from 9 to 11 years old (or 3rd to 5th graders). These
children who commute to school will perform repeated monthly measures of pulmonary function
tests using spirometry, pulmonary inflammation via exhaled breath, and asthma symptoms and
clinical encounters, up to 3 school years. These 500 children will represent 3 exposure
scenarios: 1) one group of 125 children riding retrofitted school buses or private cars; 2)
250 children riding old buses who will change to retrofitted buses during the first or
second year of the study; and 3) 125 children who ride old diesel buses through the study.
All subjects will be either healthy or having physician-diagnosed asthma with severity
ranging from mild intermittent to moderate persistent. Personal exposure monitoring of
particulate matter, CO, NO2, and SO2 will be performed on a subset of 144 asthmatic
subjects, with each subject being monitored for up to 2 days, in each monitoring year.
Subjects participating in the study will wear a small backpack containing several personal
air monitors measuring real-time particulate matter concentrations and carbon monoxide
concentrations as well as integrated (24 hour averaged) measurements of SO2 and NO2. The
children's personal monitoring will begin when they wake up in the morning and continue for
24-hours. When wearing the backpack is inconvenient, such as when sleeping, the monitoring
equipment should be placed in close proximity to the subject. Once the subject arrives at
school, s/he will be asked to perform three respiratory tests: exhaled nitric oxide, exhaled
breath condensate, and spirometry. At the end of the school day, the subject will be asked
to perform the same two tests of lung function as earlier, plus an additional test of
exhaled breath condensate. The subject will then continue his/her day as normal. A
technician will replace the filter in the particulate matter monitor between 6 and 7 PM. We
will repeat the same monitoring procedure the following morning when the subject wakes up
for another 24-h. Monitoring will stop on the third morning when the subjects wake up. In
addition to the personal monitoring, a monitoring kit will be installed in the subject's
school bus and will be operated by a technician. This in-vehicle monitoring kit includes
everything contained in the personal monitoring kit, plus a P-TRAK (TSI, model 8525) for
real-time ultra-fine particle counts, two Harvard Personal Environmental Monitors (HPEM)
with Teflon and quartz filters respectively for determining elemental carbon fractions, an
EcoChem PAS2000CE monitor for polycyclic aromatic hydrocarbons (PAHs), and a global
positioning system personal acquisition logger (GPS-PAL). The following timeline shows the
typical daily schedule for a subject participating in the study.
children who commute to school will perform repeated monthly measures of pulmonary function
tests using spirometry, pulmonary inflammation via exhaled breath, and asthma symptoms and
clinical encounters, up to 3 school years. These 500 children will represent 3 exposure
scenarios: 1) one group of 125 children riding retrofitted school buses or private cars; 2)
250 children riding old buses who will change to retrofitted buses during the first or
second year of the study; and 3) 125 children who ride old diesel buses through the study.
All subjects will be either healthy or having physician-diagnosed asthma with severity
ranging from mild intermittent to moderate persistent. Personal exposure monitoring of
particulate matter, CO, NO2, and SO2 will be performed on a subset of 144 asthmatic
subjects, with each subject being monitored for up to 2 days, in each monitoring year.
Subjects participating in the study will wear a small backpack containing several personal
air monitors measuring real-time particulate matter concentrations and carbon monoxide
concentrations as well as integrated (24 hour averaged) measurements of SO2 and NO2. The
children's personal monitoring will begin when they wake up in the morning and continue for
24-hours. When wearing the backpack is inconvenient, such as when sleeping, the monitoring
equipment should be placed in close proximity to the subject. Once the subject arrives at
school, s/he will be asked to perform three respiratory tests: exhaled nitric oxide, exhaled
breath condensate, and spirometry. At the end of the school day, the subject will be asked
to perform the same two tests of lung function as earlier, plus an additional test of
exhaled breath condensate. The subject will then continue his/her day as normal. A
technician will replace the filter in the particulate matter monitor between 6 and 7 PM. We
will repeat the same monitoring procedure the following morning when the subject wakes up
for another 24-h. Monitoring will stop on the third morning when the subjects wake up. In
addition to the personal monitoring, a monitoring kit will be installed in the subject's
school bus and will be operated by a technician. This in-vehicle monitoring kit includes
everything contained in the personal monitoring kit, plus a P-TRAK (TSI, model 8525) for
real-time ultra-fine particle counts, two Harvard Personal Environmental Monitors (HPEM)
with Teflon and quartz filters respectively for determining elemental carbon fractions, an
EcoChem PAS2000CE monitor for polycyclic aromatic hydrocarbons (PAHs), and a global
positioning system personal acquisition logger (GPS-PAL). The following timeline shows the
typical daily schedule for a subject participating in the study.
Inclusion Criteria:
- ages 6-11 and attending 1st to 5th grades at schools in one of our target districts;
approximately 75% subjects will commute by bus daily, 25% commute by car/walking;
- with or without physician-diagnosed asthma
- If with physician-diagnosed asthma:
- 1 year history, including episodic symptoms of wheezing, cough, and dyspnea;
- mild intermittent (with at least one episode a week requiring inhaler), mild
persistent, or moderate persistent severity of asthma by NAEPP Criteria (NHLBI '91);
Exclusion Criteria:
- history of smoking by the subject or by a person in the subject's home
- asthma hospitalizations within 4 weeks of the start of each study year
- other chronic diseases such as diabetes, congenital heart disease, chronic renal
disease
- new pets in the home
We found this trial at
1
site
Seattle, Washington 98195
Click here to add this to my saved trials
