Popular methods of representing pollution levels sometimes display data in “equivalent number of cigarettes smoked”, but what about actual cigarette smoke? The

Popular methods of representing pollution levels sometimes display data in “equivalent number of cigarettes smoked”, but what about actual cigarette smoke? There’s an interesting difference between actual pollution levels and what is perceptible. You can’t as easily detect the odour of nitrogen dioxide or micro particles from brakes. I imagine cigarette smoke accounts for very little pollution measured by typical methods, but walking down a busy street in London you’re likely to pass through dense clouds of it every few meters. I wonder how much difference this concentrated method of delivery makes to the effective toxicity.