As humans, we're suckers for relying on the influence of others around us. This is why we're more likely to don our running shoes if everyone else in our neighborhood seems to be out exercising. It's why environmental psychologists believe we're more likely to recycle if we see our neighbors recycle, too. It's why public health researchers talk about "social contagion."
And this is also why concerned parents and policymakers have long been worried about cigarettes on the street. If kids see people smoking everywhere, the thinking goes, they'll grow up believing the behavior is entirely normal and acceptable. And that social influence might as well be just as bad as the second-hand smoke.
Social influence is particularly difficult to measure. But researchers in New Zealand have come up with one potential method on the cigarette front: mapping smoking visibility on local city streets. The result is a fascinating cross-pollination of geospatial data and public health.
Their technique could easily be replicated on American streets, or extended to study the visual effects of just about any naughty or beneficial public behavior (drinking 16-ounce sodas, chewing tobacco, biking). This study is the kind of thing that Michael Bloomberg would love.
The researchers -- Amber Pearson and George Thomson of the University of Otago and Daniel Nutsford of the University of Canterbury -- collected 28 hours of observational data on 411 smokers outside bars and restaurants in downtown Wellington. They then used the data to create three-dimensional "viewsheds" of smoking on a map of the city's central business district, taking into account the actual height and footprints of local buildings and the plausible sight lines around them.
Here is one result from their findings published in the journal BMC Public Health. It's a map illustrating how much visual exposure to smoking we're likely to experience on a Friday night in downtown Wellington from any given viewpoint:
This map doesn't capture smokers strolling down the street, leaning out of passing cars or simply congregating outside other buildings (it also ignores the ability to see smokers from a nearby balcony or window). But the smoking outside of bars and restaurants alone was pretty pervasive. At one venue, the study counted 44 lit cigarettes in one 15-minute window. At night, bars showed on average 10 lit cigarettes per 15-minute time frame.
The map above also shows that streets with a lot of retail and restaurants were (visual) smoking hotspots, particularly at night. Here are two contrasting views during the day:
As for what this might look like in the United States, smoking rates are higher here than in New Zealand. Laws on where you can smoke in public also vary dramatically depending on the city (in new Zealand, public smoking is legal outside parks and playgrounds).
The authors suggest that places with "strong pedestrian cultures" like Europe probably have to worry more about visible smoking. That is arguably less of a problem in the United States.