Air pollution and criminal behavior: a nationwide case-crossover analysis in China

Criminal activity is a major societal and public health concern. However, little is known about how exposure to ambient air pollution influences the incidence of crime. We aimed to examine the short-term associations between air pollution and criminal behavior.

We used a nationwide time-stratified case-crossover design to analyse 483 718 crime events in China (2013-19). Conditional logistic regression models were employed to estimate associations between individual pollutants and crime, while weighted quantile sum (WQS) regression was used to assess joint effects. Stratified analyses were conducted by crime type, season, geographic region, and socioeconomic status. An Air Quality Score was constructed to facilitate interpretation.

All six examined pollutants, i.e. fine particulate matter, coarse particulate matter, nitrogen dioxide, carbon monoxide, sulfur dioxide, and ozone, were associated with increased crime incidence, with the largest estimates observed on the day of exposure. Each interquartile range increase corresponded to increases of 1.66%, 1.88%, 4.03%, 2.03%, 2.81%, and 1.30%, respectively. Associations were stronger in the cold season, northern regions, and lower-socioeconomic regions, with consistently stronger associations observed for violent crimes and theft across the examined pollutants. Moreover, a one-unit increase in the WQS index was associated with a 3.22% increase in crime incidence.

Short-term exposure to air pollution is associated with increased crime incidence, as evidenced by both independent and joint-pollutant effects. These findings suggest that joint exposure to multiple pollutants may be relevant to crime incidence. Improving air quality may have potential co-benefits for public safety.