· We are facing more extreme weather events from air pollution and climate change, and the social costs may also include more aggressive behaviour.

• Dog bites may occur more frequently during hot, sunny weather and when air pollution is high.

According to the American Veterinary Medical Association, dog bites mainly occur in response to something, such as stress, panic, fright or threat, or to protect food, toys or puppies.

Are you more likely to be bitten by dogs in smog?

"It's not common for dogs to hurt people. The best way to avoid it is to understand how dogs behave and how to interact with them. However, we still have to be more careful in hot weather or when air pollution is high." June On the 14th, Clas Linnman, an assistant professor of physical medicine and rehabilitation at the Spaulding Rehabilitation Hospital in Boston, USA, and a researcher at the Spaulding Neuroimaging Laboratory, said in an interview with The Paper.

On the evening of the 15th, a research paper by Clas Linnman as the corresponding author was published online in the international academic journal "Scientific Reports". The title of the paper is "The risk of being bitten by a dog is higher on hot, sunny, and smoggy days."

The paper cites the American Veterinary Medical Association as saying that dog bites occur primarily as a response to something, such as stress, panic, startle or threat, or to protect food, toys or puppies.

Previous research has shown that humans commit more violent crimes when temperatures and air pollution are higher, the paper said. So, is the incidence of dog-bite incidents also affected by environmental factors? The researchers analyzed 69,525 recorded reports of dog bites. The results showed that the incidence of dog bites increased with temperature and ozone levels, but not with PM2.5 exposure. In addition, the researchers observed that higher levels of UV radiation were associated with higher rates of dog bites. They concluded that dog-to-dog, or human-to-dog interactions were more hostile on hot, sunny or air-polluted days, implying that the societal burden of extreme heat and air pollution also includes animal aggression .

Claes Linmann and colleagues investigated and analyzed the data of dog bite incidents in 8 cities including Dallas, Houston, Baltimore, Chicago, Los Angeles and New York City in the United States from 2009 to 2018: a total of 69,525 dog bite incidents in 10 years, On average 3 cases per day.

The results of their analysis suggest that dog bites may occur more frequently during hot, sunny weather and when air pollution levels are higher. Dog bites increased by 11 percent on days with high UV levels, 4 percent on days with high temperatures, and 3 percent on days with high ozone levels.

But on days with high rainfall levels, dog bites fell slightly, by 1%. Levels of PM2.5 appeared to have no effect on the frequency of dog bite incidents. The risk of dog bite incidents decreased slightly on weekends and holidays.

The researchers believe that ozone may affect canine aggression by causing lung inflammation, activating the stress response, and affecting dopamine metabolism in the striatum. Elevated ozone levels in winter, not only in summer, can also increase the risk of dog bite incidents. On sunny days, temperatures and UV radiation levels are likely to be higher.

Claes Linmann told The Paper that their newly published findings extend previous research on violent crime rising with rising temperatures and air pollution, "We now know that dogs are also affected by these environmental factors. This is important because we are facing more extreme weather events from air pollution and climate change , so the social costs may also include more aggressive behaviour."

In addition, the paper reminds that the study only included data from 2009 to 2019, and did not include data from the COVID-19 period in the past few years . Although the air pollution decreased during this period of blockade and isolation, the number of patients with dog bites in pediatric emergency departments in relevant cities in the United States increased . This may be due to other factors, such as forced close contact.

The authors note that the data sources they used may only reflect more serious dog bite incidents. Relevant records do not include other factors that may affect an individual dog's risk of injury, such as breed, sex, neutering status, and severity of the bite, age, sex, familiarity with the dog, and interactions leading to the bite, etc. information.