Here is a sampling of recent peer-reviewed articles about the effects of air particulates, smog, and ozone.

Persistent endothelial dysfunction in humans after diesel exhaust inhalation.
Am J Respir Crit Care Med. 2007 Aug 15;176(4):395-400.
http://ajrccm.atsjournals.org/cgi/content/full/176/4/395

Exposure to diesel exhaust induces changes in EEG in human volunteers.
Part Fibre Toxicol. 2008 Mar 11;5:4.
http://www.particleandfibretoxicology.com/content/5/1/4

Chronic exposure to ambient ozone and asthma hospital admissions among children.
Environmental Health Perspectives 2008 116(12)1725-1730.
http://ehp.niehs.nih.gov/members/2008/11184/11184.html

Endothelial dysfunction: associations with exposure to ambient fine particles in diabetic individuals.
Environmental Health Perspectives 2008 116(12)1666-1674.
http://ehp.niehs.nih.gov/members/2008/11666/11666.html

The Adverse Effect of Low Levels of Ambient Air Pollutants on Lung Function Growth in Preadolescent Children
http://ehp.niehs.nih.gov/members/1999/107p669-674jedrychowski/jedrychowski-full.html