www.arb.ca.gov health impacts of diesel particulate matter http://www.arb.ca.gov/research/diesel/diesel-health.htm health concerns www.arb.ca.gov Air Resources Board www.arb.ca.gov sounded the alarm early http://www.arb.ca.gov/research/diesel/diesel-health.htm Health Effects health impacts of diesel particulate matter Diesel exhaust contains known carcinogens