Canadian Study of Exposure of Children to School Bus Exhaust

1. Canadian Study of Exposure of Children to School Bus Exhaust New Brunswick Lung Association New Brunswick Dept. of Education Health Canada Environment Canada Dr. David Brown EHHI, Dr Thelma Green RPC

2. Diesel emissions are a complex mixture of hazardous particles, gases and vapours CO2 PM1.0, PM2.5 CO, VOCs including polycyclic aromatic hydrocarbons benzene, 1,3-butadiene, toluene and xylene, aldehydes

3. Health effects Symptoms most often associated with diesel exhaust exposure are: irritation of the eyes and nose broncho-constriction cough and signs of laboured breathing chest tightness and wheezing Diesel exhaust is a probable human carcinogen.

4. Population health Respiratory diseases are increasing in North America and are becoming one of the leading causes of death (Statistics Canada, 1997) Air pollution plays an important role in the development of several respiratory conditions: infections such as bronchitis and pneumonia exacerbation of chronic obstructive lung disease and asthma decreased lung function and lung growth lung cancer It also contributes to higher rates of heart attacks.

5. Asthma and children Studies have shown a causal relationship between traffic congestion, diesel exhaust and asthma (English et al., 1999; Ciccone et al., 1998, cited in Wargo et al., 2002). Asthma accounts for one quarter of school absenteeism and is the most common chronic disease plaguing children. In 2000/01, 8.7% of Canadians four years of age and over suffered from asthma. Between 1995 and 1999 the prevalence of asthma had increased by 14% among children between ages 4 and 11. It occurs currently in approximately 7 to 10% of children (Health Canada, 2002; Canadian Lung Association, 2004) In New Brunswick, in 2000/01, there were 8652 young people between the ages of 12 and 19 suffering from asthma.

6. School Bus Study • Objectives • To determine the exposure of New Brunswick children to fuel exhaust-related pollutants on their daily way to school. • To improve our understanding of the exposure of New Brunswick school children to diesel exhaust relative to the age of the bus and the length of the bus route. • To offer policy recommendations based on the findings.

7. Methods • Compounds measured were PM 1.0, PM 2.5, black carbon, and volatile organic compounds. • A Dust Trak air monitor sampled continuous levels of particulate matter 2.5 g and smaller. A P-Trak sampled PM 1.0 g and smaller. An aethalometer measured levels of black carbon (BC) and UV-absorbing aromatic material. SUMMA cannisters were used to take “total-trip” samples of volatile organic compounds (VOCs). • Ambient PM 2.5, temperature, precipitation, humidity and wind data were collected. • The research assistants recorded all relevant events in a log for each entire day. • Data exists for 63 sampling days, over 86 bus rides and 20 walking routes.

8. Results • The study found that the levels of pollutants on New Brunswick School buses is actually lower than levels found in previous studies in Los Angeles, Connecticut and British Columbia. As well, old and new buses had similar levels of exhaust pollutants, indicating that the buses are well-maintained. • Variability in the data was high, reflecting exposures associated with variable and real differences in buses, trip characteristics, weather and traffic.

9. Results Riding the bus on routes with high exposures exposes children to 3-5 times higher levels of PM2.5, and 2-3 times higher PM1.0 than does walking to school. Levels of VOCs were higher on buses but the variability could not be explained by age of bus or duration of route. Short bus rides have higher mean and maximum exposures to PM2.5. Long bus rides had higher cumulative exposures to PM2.5, PM1.0 and black carbon compared with short rides. The age, mileage, and type of fuel injection system (mechanical or electric) did not strongly affect exposures to PM2.5. Colder temperatures tended to increase PM1.0 and higher humidity increased PM2.5. Higher ambient PM2.5 tended to increase PM2.5 inside buses. Remember ambient PM is highly affected by weather conditions.

10. Examples PM2.5 exposure Walking Riding the bus

11. Same bus ride: PM1.0, Black carbon, PM2.5 PM1.0 counts/m3 Black Carbon ng/m3 PM2.5 ug/m3

12. Recommendations Eliminate bus idling Implement no-idling policy for all vehicles on school grounds Avoid caravanning Consider reducing the number of stops or relocating stops to areas with lower traffic density Locate exhaust pipes to upper left of rear of bus. Breather tube should be exhausted to the outside. Air-filtering systems should be considered Retrofit diesel buses to achieve lower emissions New buses should have lowest emissions possible

13. Reducing barriers Ensure all appropriate partners are included in study. Hold several meetings as necessary to bring groups on-side (government officials, school bus drivers, maintenance workers, teachers, children, parents, researchers, ethics committee) Increase awareness of all partners on importance of gaining new information on exposures and health effects Ensure methods and report are based on newest scientific thinking Agree on communication strategy and cautions at beginning- School buses are the safest way to transport children to school Be trustworthy in reporting findings in non-inflammatory way Provide authorities with all opportunities to be proactive in actions to reduce risk. Prior to the release of the study, the New Brunswick Department of Education passed a province-wide no-idling policy for school buses- the first such provincial policy in Canada.