1. Health Effects: Diesel Exhaust Maureen Edwards, MD, MPH Center for Maternal & Child Health MD Dept. Health & Mental Hygiene Medwards@dhmh.state.md.us

2. Diesel Exhaust Complex mixture of gases and fine particles Gaseous fraction---nitrogen, oxygen, carbon dioxide, water vapor & air pollutants, such as: carbon monoxide, sulfur oxides, nitrogen oxides, volatile organics, alkenes, aromatic hydrocarbons, and aldehydes Ultrafine particles with chemicals adsorbed

3. Health Concerns Diesel Exhaust: Acute or Short-Term Exposure Acute irritation – Eye, throat, bronchials Neurophysiological – Lightheadedness, nausea  lung function & respiratory symptoms – Cough, mucus, labored breathing, chest tightness, wheezing

4. Health Concerns Diesel Exhaust/Particulates: Chronic or Long-Term Exposure Likely carcinogenic (lungs), primarily occupational exposures Noncancer respiratory effects – Lung inflammation and cell changes Cough, mucus, chronic bronchitis Immunologic reactions with increase response to allergens Initiation asthma, asthma “attacks,” increased allergic symptoms

5. Relation diesel exposure & ill health? Length of exposure Specific component of diesel exhaust Sensitivity of individual

6. Special risks to children: Children breathe more rapidly More often breathe through mouth More time outdoors Closer to ground Have smaller airways Have immature lungs Therefore, at greater risk from exposures in the air

7. Breathing rates Infant Adult Respiratory volume 1010 (ml/kg/breath) Respiration rate 4015 (breaths/min) Minute ventilation 400150 (ml/kg/min)

9. Asthma Chronic respiratory disease with inflammation of the airways. Bronchial hyper-responsiveness and episodic reversible airway obstruction. Genetic & environmental factors contribute to its development. Indoor & outdoor triggers lead to “attacks.” Controlled by avoidance of triggers & regular medication.

11. Asthma: Maryland Children 11 % or >150,000 have a history of asthma >14,000 emergency department visits 2002 >2500 hospitalizations 2002 7 children died (2003), 2 (2002)

12. Children & School Buses MarylandUS Children transported 622,82024,000,000 Total route miles per year 124,175,994>4,000,000,000 Total vehicles6650454,000

13. Children’s diesel exposure Bus: – Age of bus, type of fuel, filters Bus ride: – Time on bus, idling, open/closed windows, airflow, back/front of bus Other exposures to combustion products

14. Children’s Environmental Health Protection Limit exposure to all potential toxins Concern for most sensitive population – Children, persons with asthma Invoke the “precautionary principle” – Extra factor for safety if exposure not proven safe