Though physiological effects of exposure to airborne lead on cognitive function and crime have been discussed in literature, to date, no studies examined other outdoor or ambient air pollutants and their potential impact on reported crime. Data were collected through open public records provided by study location municipalities to assess the impact of outdoor air pollution on daily crime rates in Chicago, Houston, Philadelphia, and Seattle. Poisson regression analyses were performed to examine associations between outdoor air concentrations of carbon monoxide (CO), particulate matter (PM) including fi ne (PM2.5) and coarse (PM10) respirable fractions, ozone (O3), and sulfur dioxide (SO2) with several types of crime along with weather variables known to correlate with air pollution concentrations and/or impact crime. Increased PM2.5 was associated with increases in assault, damage, and theft crimes. Pollutants known to cause irritation, like PM10 and O3, were associated with decreases in crime rates. Weather variables were also found to be associated with increases in crime rates when apparent temperature, cloud cover, visibility, and wind speed increased from the 25th to 75th percentile of measurements. Additional research to further understand potential relationships between outdoor air quality and crime is needed. [ABSTRACT FROM AUTHOR]