A research done in my city's main train station showed 400,000 UFP particles per cubic centimetre.

I am looking into printing pamphlets and wanted to inquire how does spending half an hour in a 400,000/cm^3 environment compare with smoking when it comes to lungs damage. It can be a rough estimation, something along the lines of: "Spending half an hour in those conditions is equivalent to smoking 5 cigarettes".

The research: "Measurements of air pollution with nanoparticles and evaluation of the passengers' exposure in the Jerusalem central bus station and in the departing buses and also in the Shalom train station and in the departing trains" (pdf). English starts on page 12.

  • 2
    Thanks for adding a link to the report! I was wondering where exactly you got the 400,000 PM2.5/cm2 from because I don't see any PM2.5 measurements in the English part of the report. Only NOx and UFP measurements.
    – THelper
    Commented Nov 22, 2018 at 12:26
  • You are probably right. The 400,000 figure is mentioned on page 45 on the second graph, in the first carriage of a train in pull mode. The axis says "Average UFP per cm^3".
    – Guy
    Commented Nov 22, 2018 at 17:18
  • The first table on page 55 has the figure regarding pollution on the station. Point 2 averaged 194,154 per cm^3 or roughly 200K per cm^3. I am wondering how can I explain those number in common language to spread awareness.
    – Guy
    Commented Nov 22, 2018 at 17:21

1 Answer 1


On average, smoking one cigarette results in inhalation of roughly 600 billion ultrafine particles (UFP).

From a joint research study by universities in Lebanon, the U.S., and France: "Comparison of carcinogen, carbon monoxide, and ultrafine particle emissions from narghile waterpipe and cigarette smoking: Sidestream smoke measurements and assessment of second-hand smoke emission factors"

The average adult human inhales about 10 liters of air per minute while standing.

From research by the California Environmental Protection Agency: "Research Note 94-11: Topic = How Much Air Do We Breathe?"

Thus breathing air at the station with a concentration of 400,000 UFP particles per cm3 for one hour is the same as smoking 0.4 cigarettes; or every 2.5 hours spent at the station is the same as smoking one cigarette.

(1000 cm3 / l) * (10 l / min) * (60 min / hr) * (400,000 UFP / cm3) * 
(1 cigarette / 600,000,000,000 UFP) = 0.4 cigarette / hr
  • Cheers for the answer. According to this, spending time at the station is not as bad as I initially thought. Moreover, this gave me some new insights on cigarettes - cigarettes are worse than I thought.. I am not smoking but I will for sure pass this information to any of my smoking friends.
    – Guy
    Commented Nov 23, 2018 at 19:43

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