“Prior to the late 19th century, night air was considered dangerous in most Western cultures …”

~ Wikipedia

“Wherever the cloud of pollution travels, crime increases.”

~ Sefi Roth

The idea has been rebuffed by modern science and our understanding of contagion (not withstanding anti-vaxxers), but according to Wikipedia: “Based on “zymotic” theory, people believed vapors called “miasmata” (singular: “miasma”) rose from the soil and spread diseases. Miasmata were believed to come from rotting vegetation and foul water — especially in swamps and urban ghettos. … Miasma was considered to be a poisonous vapor or mist filled with particles from decomposed matter (miasmata) that caused illnesses. The miasmatic position was that diseases were the product of environmental factors such as contaminated water, foul air, and poor hygienic conditions. Such infection was not passed between individuals but would affect individuals within the locale that gave rise to such vapors.”

But we do know that, in times gone by, we did have lots of dangerous emissions. They ranged from smoke from wood and coal heating and cooking fuels, to dust from animal and human excrement, to pollution from local industries … not to mention TB, influenza and other germs circulating in poorly ventilated rooms. With the industrial revolution, pollution reached an industrial scale and flourished in the US until the environmental protection laws of the ‘60’s and ‘70’s were passed. Then, finally, we began to turn the tide of air pollution health effects.

Sadly, now, the trend is backwards. And the effects may not be entirely limited to obvious problems. According to science journalist Melissa Hogenboom, “Emerging studies show that air pollution is linked to impaired judgement, mental health problems, poorer performance in school and most worryingly perhaps, higher levels of crime.”

Reminiscent of a Dickens novel, recent studies have shown that air pollution can actually impact many social factors. Hogenboom reported on work by Sefi Roth, a researcher at the London School of Economics. “In 2018 research, his team analyzed two years of crime data from over 600 of London’s electoral wards, and found that more petty crimes occurred on the most polluted days, in both rich and poor areas.” Also, MIT research “found that ‘air pollution predicted six major categories of crime’, including manslaughter, rape, robbery, stealing cars, theft and assault. The cities highest in pollution also had the highest crime rates.”

Hogenboom continues, “These findings are all the more alarming, given that more than half of the world’s population now live in urban environments — and more of us are travelling in congested areas than ever before. Staggeringly, the World Health Organization says nine out of 10 of us frequently breathe in dangerous levels of polluted air.”

The Nature Conservancy looks to the future: “The 21st century will be the urban century, as more than 2 billion additional people arrive in cities globally. … by 2050, the vast majority of humanity will live in cities, towns, and other urban areas. … Among the most pressing of global urban environmental challenges is air quality.”

Battling urban air quality becomes an increasing challenge. However, The Nature Conservancy has a solution: “The humble street tree is an ecological powerhouse. Trees and other natural features in cities can help regulate water quality, water quantity, and the timing of water flow. They can help clean and cool the air, reducing harmful air pollutants and ambient air temperatures. They lend beauty to our streets, enhance citizens’ lives, and significantly increase property values. When you consider all the benefits that street trees can provide to society, there is a strong business case for increased societal investment.”

So, obviously, we need to invest in green infrastructure. Get your neighbors and local governments to plant trees, plant shrubbery, and build parks and greenways. It’s good for our physical and mental health, but just as important, it helps combat crime.

Think of it as “grime-fighting helps crime-fighting,” or maybe just “air on the side of caution”.

Additional information:
Melissa Hogenboom, How Air Pollution is Doing More than Killing Us, 16 April 2019, BBC Future

The Nature Conservancy, Planting Healthy Air, A global Analysis of the Role of Urban Trees in Addressing Particulate Matter Pollution and Extreme Heat, 8/25/2016

The Nature Conservancy, Funding Trees for Health, An Analysis of Finance and Policy Actions to Enable Tree Planting for Public Health, 9/25/17

American Lung Association, State of The Air 2016, Lung.Org