- Research suggests pollen allergies make people temporarily less violent.
Around one in five people suffers from allergic rhinitis — often called hay fever — and frequently experiences the nasal congestion, runny nose and watery eyes that accompany high-pollen days. Other symptoms of such seasonal allergies include mood changes, fatigue and reduced sleep.
Pollen allergies can certainly make or break your day if you have to call in sick to work, or take medication that makes you drowsy. New research, however, suggests something surprising: Allergies might also stop people from committing acts of violence.
A study published last month in the Journal of Health Economics found that the rate of violent crime was 4 percent lower than normal on high-pollen days. Researchers used data from 16 cities, including Colorado Springs, to reach that conclusion.
While 4 percent may not seem like much, the report — titled “More sneezing, less crime?” — notes that previous studies have associated the same level of crime reduction with hiring 10 percent more police officers.
It seems that the allergic symptoms and corresponding lethargy that comes from high pollen counts could keep someone from committing a crime, Deza says, by changing the “situational factors” that trigger violence.
Deza and her co-authors found inspiration from a recent study showing high-pollen days had a significant negative effect on third-grade test scores. They decided to look at pollen through the lenses of economics and criminology.
“If you study a determinant of crime, the classic ones will always be criminal justice policy,” Deza says. “But then, whatever policy you’re exposed to today, you’re exposed to tomorrow, and the day after, and the day after and future generations, and so on, right? And you can adjust to it more slowly.
“There’s certain things like pollution similarly, to some extent, they build up on your system, but pollen allergies, there’s ... so much daily variation,” she adds.
It’s also true that pollen counts — especially for weed pollen — are much higher now than in the past, thanks to a warming climate, says Dr. Daniel Soteres of Asthma & Allergy Associates, a local clinic and research center.
“We definitely know from current data that because of climate change, an individual ragweed plant produces ... more pollen in a high-CO2, warmer climate than it does in the climate from 30 or 50 years ago,” Soteres says.
He calls the theory linking pollen to crime “interesting,” and thinks it warrants “further research and more careful analysis.”
“Is this also associated with, it’s just hotter than heck outside also at that time of year, and does that affect crime in general?” he posits.
That said, Soteres points out that pollen is a big deal. Many of us may now take over-the-counter allergy medications for granted, but hay fever used to be a much bigger social problem. Even now, he says, “environmental allergies have a bigger impact on quality of life than a lot of people think.”
Does the pollen study have policy implications? Deza and her colleagues don’t necessarily recommend that everyone move right next to a park with plenty of weeds and trees so that crime decreases, she jokes.
However, the research may have important implications in the realm of behavioral health.
The study used data from one city, New York, to examine whether high pollen days decreased violent crime simply because more people stayed home and did not commit crimes on the streets. If so, the researchers expected to see fewer crimes outside and more crimes inside homes.
Instead, they found the opposite: “There is a sizable decrease (4.4%) in residential violence on high pollen days, and no statistically significant change in outdoor violence,” the report says, meaning that “this is not merely a story about a change in opportunity or routine activities.”
Thus, allergies would appear to have a direct effect on the likelihood someone will commit a violent crime.
Deza believes the larger takeaway is that people often commit violence based on situational factors — in this case, whether they’re feeling healthy. Therefore, she thinks the study supports an argument for mental health services to help young offenders learn better self-control and anger management.
“If it takes something like a health shock to make people — to prevent this situation of domestic, residential violence,” Deza says, “maybe these programs that teach people how to think before they act — how to not respond so instantaneously with violence — those might actually have long-term consequences.”
Other factors that could affect crimeCriminologists tend to agree that when you increase the size of the police force, crime rates go down. (Increasing the number of people in prison — a tactic once seen as a clear answer to crime — may have smaller effects than we once thought.) When the economy is solid, and there are plenty of jobs to go around, the crime rate also predictably trends downward.
But limited research also points to other, less obvious factors that could be correlated with an increase or a decrease in crimes. Here are just a few examples:
Air pollution: A forthcoming study by Colorado State University researchers suggests a connection between higher levels of ozone and violent crime. Previous studies — including 2018 research from the Massachusetts Institute of Technology that linked air pollution to manslaughter, rape, car theft and assault — have reached similar conclusions.
Football games: Economists David Card and Gordon Dahl found reports of domestic violence spiked by 10 percent in the hour after a local NFL football team suffers a loss. Other studies have shown that an upset loss triggers more violent crimes than an expected loss — and that crimes still increase on game days when the home team wins, but not to the same extent.
Temperature: In multiple scientific studies, researchers have found that temperature significantly affects the crime rate. One example: A study in Finland found that temperatures accounted for 10 percent of fluctuations in the country’s rate of violent crime, which rose by 1.7 percent for every one degree Celsius (1.8 degrees Fahrenheit) increase in temperature.
Exposure to lead: The hypothesis is spine-chilling — lead, used in paint until 1978 and in gasoline until 1996, caused a corresponding spike in violent crime in the 1970s and 1980s. Lead poisoning in young children can inhibit brain development, and studies show childhood exposure increases the likelihood people will be arrested and incarcerated later in life. There’s a large body of research dedicated to this theory.
Though researchers used rigorous methods to research all of the above potential factors, and published their reports in reputable journals, it’s difficult to definitively prove a link between crime and other, seemingly unrelated variables.
Still, they provide some great food for thought.