Secrets of Vivergy Calculations Unveiled (Part 3 of 3)

(This is the final part of a new series which will describe how to do your own air pollution to secondhand smoke calculations)

Here at Vivergy, we go out of our way to share what we know about air pollution, and help others understand how they might be able to better connect with such a complex scientific topic. We have really pushed to find ways to connect the data to each and every person across the United States, and avoid the trap of discussing the science in ways that are difficult to comprehend. We convey air pollution in three separate ways on the Vivergy platform: number of cigarettes inhaled per year, months of the year living with a smoker, and time spent in a sealed car with a smoker. Today, we want to let you know how to do your very own air pollution to months living with a smoker calculation. Using these methods, you can convert any air pollution data measured in fine particulate matter (PM2.5). If you want to learn how to convert PM2.5 numbers to time spent in a car with a smoker, you can check out Part 2! If you want to learn how to convert PM2.5 numbers to cigarettes, you can check out Part 1!

In order to compare the two, we make a fundamental assumption that the particulate matter in air pollution has the same makeup as the particulate matter in cigarettes. Fine particulate matter is a general class of pollutant that encompasses any airborne particle less than 2.5 micrometers in diameter. It is a standard measure of air pollution due to its harmful nature and its general application across all air systems. The smoke that one inhales when smoking a cigarette also falls under this class of particulate.

Here is the key for this calculation: if you think about it, the level of PM2.5 in a house with a smoker is relative to the ambient level at the house’s location (since the air inside has to come from somewhere!).

In a Formula:

Indoor PM2.5 = Outdoor PM2.5 + Secondhand Smoke PM2.5 + Other Household Sources of PM2.5

According to multiple studies on the matter (you can check out the EPA study below), houses that contain a smoker have an average 30 ug/m3 higher level of PM2.5 than houses in similar areas that do not have resident smokers. This is the biggest part, now all you need is the PM2.5 level for your particular area!

Let’s say your area averages 10 ug/m3 of particulate matter over the course of the year.

Equivalent Time Living With A Smoker = (Annual Average PM2.5)/((Annual Average PM2.5) + (Difference For Living With A Smoker))

Equivalent Time Living With A Smoker = 10/ (10 +30) = 25% of the year with a smoker. Put in concrete terms, that is 3 months of the year with a smoker.

What about New Delhi in India, where average PM 2.5 level is a whopping 153?

153/ (153 +30)= 83%= 10 months of the year with a smoker. So, living in New Delhi is nearly indistinguishable from living with a smoker year-round.

–The Vivergy Team


Clayton CA, Perritt RL, Pellizzari ED, Thomas KW, Whitmore RW, Wallace LA, Ozkaynak H, Spengler JD. Particle Total Exposure Assessment Methodology (PTEAM) study: distributions of aerosol and elemental concentrations in personal, indoor, and outdoor air samples in a southern California community. J Expo Anal Environ Epidemiol. 1993 Apr-Jun;3(2):227-50. PubMed PMID: 7694700.