From the Daily Mail...
Why walking within 30ft of a lit cigarette puts you at risk of dangerous passive smoking
Pedestrians passing pub and office doorways are being exposed to dangerous levels of passive smoking, say researchers.
A study showed that a single lit cigarette can pollute the air nearly 30ft away.
Passers-by walking any closer to where smokers are congregated can inhale 100 times more fumes than the limit recommended by experts in the US.
Firstly, bollocks. Secondly, what "fumes" are these? Experts, in the US or anywhere else, do not have a safe limit for "fumes". America's Occupational Safety and Health Administration (OSHA) has permissible limits for specific chemicals in the workplace, but they have never found that the chemicals in secondhand smoke exceed their limits in indoor, let alone, outdoor settings.
Campaigners say the smoking ban in enclosed workplaces has simply shifted the problem of passive smoking outdoors.
Wasn't that the whole point of smoking bans, as campaigned for by "campaigners" (in this instance, the taxpayer-funded Tobacco Free Futures)? Smoking bans turn secondhand tobacco smoke, which is so heavily mixed with indoor air that any harm to bystanders is questionable, into secondhand tobacco smoke that is so vastly mixed with outdoor air that the risks become not merely infinitesimal but risible.
The study by Seoul National University, South Korea, published in the journal Nicotine And Tobacco Research, measured air quality at various distances from a lit cigarette on a rooftop.
Smoking was simulated by a machine which mimics the inhaling and exhaling of fumes.
What a relief to know that no smokers harmed themselves during this experiment.
Researchers measured the number of polluting fine particles per cubic metre of air.
Before the cigarette was lit, the background level was around 35, the threshold set by the US National Ambient Air Quality Standard.
But at 3ft from the lit cigarette, levels averaged 107.3 and peaked at 3,254.6 when the monitor was downwind. At 29ft 6in away (nine metres), the level still reached 99.1.
Regular readers—indeed, anyone who can read—will know better than to take science reporting from the Daily Mail too seriously. The study in question appears to be this effort which looks at fine particulate matter (PM2.5) and the numbers given by the Mail above are simply wrong.
The EU has an daily average limit of 50µg/m3 for PM2.5, which will be lowered to 25µg/m3 in 2015 (the Mail is correct in saying that the US has a limit of 35µg/m3). The EU stipulates that this limit must not be exceeded on more than 35 days in a year. It is a limit on constant, ambient air pollution and in no way implies harm from brief exposure.
The researchers in this study set up smoking apparatus on an outdoor roof terrace (where I very much doubt the "background level was around 35", by the way) and found that average PM2.5 exposures were as follows:
1 metre from cigarette: 72.7 µg/m3
3 metres from cigarette: 11.3 µg/m3
6 metres from cigarette: 4.1 µg/m3
9 metres (ie. the Daily Mail's 30 feet): 2.6 µg/m3
In other words, PM2.5 exposure only exceeded the EU's (and the USA's) daily 24 hour limit when the person was within a metre or so of the smoker. Beyond that, it was well below the limits which—I must stress once more—are limits for constant ambient air quality, not occasional exposure.
So, if you spend your whole life standing nose-to-nose with someone who literally never stops smoking, you may find yourself exposed to fine particulate pollution that is somewhat higher than the EU's limit for air pollution.
But as for "walking within 30ft of a lit cigarette" putting you at risk of "dangerous levels of passive smoking", it won't. Levels of PM2.5 are much higher on the average London street than they are within a few metres of burning cigarettes in this study. It's a scare story put forward in a press release by an anti-smoking state-funded sock-puppet and regurgitated by the least scientifically literate newspaper in the land.