It's one of those things so mundane and commonplace, most of us probably don't even notice when it happens, let alone get worked up over it.
I don't know why it bugged me so much when I saw it again the other day.
I was driving on the 10 Freeway and watching as the driver ahead of me and his passenger casually flicked cigarette ashes out their windows as they chatted. Then, as they finished their smokes, first one and then the other tossed their butts onto the road.
This town is a lot of things. One thing it's not is an ashtray. But this got me wondering: How many cigarette butts get littered every year, and what does that do to the environment?
And what can we do about it?
"For people who smoke, tossing a butt on the ground is part of the whole ritual," said Thomas Novotny, a professor of epidemiology at UC San Francisco who focuses on cigarette butts. "It's not considered litter."
In fact, cigarette butts are among the most common forms of litter nationwide. The Los Angeles County Department of Public Works estimates that local smokers drop 600,000 butts on the ground every month, or more than 7 million a year.
"By a mile, the No. 1 item that we find at beach cleanups is cigarette butts," said Mark Gold, president of Heal the Bay, a Southern California environmental advocacy group.
According to Keep America Beautiful, a nonprofit group that compiles statistics from thousands of community cleanups nationwide, cigarette butts account for about a third of all litter in the United States.
In urban areas, the group says, cigarette butts represent as much as half of all litter on streets and sidewalks.
Put another way, the nearly 370 billion filtered cigarettes smoked in the U.S. each year result in about 135 million pounds of butts littering the landscape. Worldwide, the more than 5 trillion cigarettes consumed annually create more than 2 billion pounds of butts.
"It's a form of blight," said UCSF's Novotny.
Butts are also a long-term and potentially hazardous pollutant. Cigarette filters are made primarily of a plastic-like material called cellulose acetate. Contrary to what some smokers may believe, this material isn't biodegradable. Rather, cigarette filters gradually break down over as much as a dozen years into smaller particles that remain in the environment.
According to Novotny, the typical cigarette butt contains nicotine, arsenic, mercury, lead, cadmium, acetone and vinyl chloride.
"There have been cases," he said, "where kids have eaten cigarette butts and gotten nicotine poisoning. It's reasonable to think that marine animals face a similar risk."
Even Philip Morris, the country's leading cigarette manufacturer, acknowledges on its website that "cigarette butt litter is a significant contributor to litter in our environment today."
Bill Phelps, a spokesman for Altria Group Inc., Philip Morris' parent company, said the company was trying to get the word out to smokers that littering is a no-no.
He said Philip Morris prints the words "please do not litter" on all its cigarette packs and provides funds to Keep America Beautiful to support the group's efforts. The company also offers "portable litter devices" to customers so they can carry butts in their pocket until an ashtray or garbage can becomes available.
"The effort to reduce cigarette butt litter is part of a broader goal of reducing the environmental impact of all our products," Phelps said.
That's laudable. But admonishing smokers via cigarette packs not to litter seems about as effective as warning on those same packs that cigarettes can kill you. And when was the last time you saw a smoker stashing butts inside a "portable litter device"?
I'm all for personal choice. But when it comes to cigarettes, I draw the line at secondhand smoke and I draw the line at fouling our environment with the dregs of somebody's addiction.
Novotny is right: Casting away your butt is part of the culture of smoking. And smokers seem all but immune to litter-awareness campaigns. Stronger medicine is required.
"There's a simple answer to this," Novotny said. "Stop selling filtered cigarettes. The product can be altered to eliminate this form of pollution."
He argued that filters offer no appreciable health benefit for smokers. Although a filter may make tobacco less harsh-tasting, it does little to block carcinogens because smokers simply inhale more deeply to get the full effect of the drug.
"Filters are just a marketing tool to make cigarettes easier to smoke and seem better for you," Novotny said.
Take away the filter, he said, and you accomplish two things: You make the tobacco taste stronger and thus deter some people from smoking, and you eliminate one of the world's chief causes of litter.
Here's another idea. Charge smokers an extra dollar per pack as a deposit fee. If the smoker brings back 20 butts to any California cigarette retailer, he gets his dollar returned. If not, well, maybe someone else will do it.
I've seen enough street people going through garbage cans in search of recyclable materials to think that there'd probably be more than a few folk willing to pick up butts from the ground to score a few bucks in deposit fees.
Novotny, who will move in January from UCSF to San Diego State University, is convening a panel of experts next month in San Francisco to discuss legislative possibilities. I say, why wait?
Surely there's at least one lawmaker in Sacramento who realizes we don't want our state buried in cigarette butts. If you write the bill, I'll bang the drum. Deal?