• During this week, the lower 4 km of the troposphere was strongly affected by eastern European emissions, whereas at about 4 to 6 km we observed enhanced gaseous and particulate pollution from western Europe.

• Living close to busy traffic appears to be associated with elevated nonaccidental mortality. The evidence for other measured gaseous and particulate pollutants was not persuasive.

• Neither of the two intraurban studies attempted to include any microenvironmental exposure from the occupational setting, and control for copollutants was limited to crude markers of either gaseous or particulate exposure from government monitoring networks.