Harvard University researchers who analyzed nearly 70,000 reports of people bitten by dogs found that attacks are more likely to occur on hot, sunny and smoggy days.
Dog bite incidence increased by 11% on days with higher UV levels, 4% on days with higher temperatures and 3% on days with increased ozone levels. The attacks fell by 1% on rainy days and holidays.
The researchers studied 10 years of dog bite data collected from animal-control public records and emergency room data. Statistics from the U.S. Environmental Protection Agency, National Oceanographic and Atmospheric Administration and National Weather Service also were analyzed.
The cities investigated were Dallas; Houston; Baltimore; Chicago; Louisville, Kentucky; New York City; Los Angeles; and Baton Rouge, Louisiana.
Various studies have documented that people commit violent crimes more often when temperatures and air pollution are higher. In one study, researchers found: “On average, overall crime increases by 2.2% and violent crime by 5.7% on days with maximum daily temperatures above 85 degrees compared to days below that threshold, and heat only affects violent crimes, while property crimes are not affected by higher temperatures.”
Hotter temperatures increase aggressive motivation and aggressive behavior, according to one hypothesis, which also theorizes that people tend to perceive situations as more negative and react more aggressively when hot.
The researchers speculated that ozone might influence aggressive behavior by impacting dopamine turnover in the striatum. Ozone triggers oxidative stress in the airways and inhibits pulmonary function, and the subsequent generation of free radicals might affect behavior.
Dogs have a much larger olfactory epithelium surface area, more olfactory receptors and a larger olfactory bulb than people.