© 2008 American Thoracic Society
Particulate Air Pollution in Irish Pubs Is Grossly UnderestimatedTo the Editor:In their article, Dr. Goodman and colleagues evaluate the change in PM2.5 levels in Dublin pubs after the Irish smoking ban (1). The PM2.5 levels in pubs are most certainly log-normally distributed, so it is curious that the authors did not use a more appropriate statistical method to analyze these data, either by log-transforming the data or using nonparametric testing, as was done for the carbon monoxide and cotinine analyses. However, it is certain that the conclusion of a large improvement in indoor air quality after the smoking ban would be unaffected by this change. More importantly, due to the limitations of the light scattering instrument used in this study, the Aerocet 531 Aerosol Particulate Profiler, the PM2.5 concentrations presented in the paper are likely a gross underestimation of the true secondhand smoke (SHS)–derived particle levels. Any light scattering instrument does not measure mass concentration directly and therefore needs to be properly calibrated for the specific aerosol of interest, in this case SHS. With appropriate calibration of this device for measuring SHS, accurate SHS concentrations may be determined. We performed this calibration for the Aerocet 531 by comparing this device to the standard gravimetric method using a Personal Environmental Monitor (PEM for PM2.5). These experiments determined a calibration factor for the Aerocet 531 for measuring SHS of 8.3 (95% CI, 6.9 – 9.8). This means that the average preban PM2.5 level in the Irish pubs was likely about 8.3 times higher than the level stated by Goodman and colleagues (1), or 295 µg/m3. After adjusting the results of this study with the appropriate calibration factor, they are much more consistent with other similar studies (2–5). The more accurate PM2.5 concentration puts in perspective just how high the levels of particulate air pollution are in pubs with smoking. PM2.5 concentrations of this magnitude are rarely if ever seen in outdoor air, are deemed "hazardous" by the U.S. Environmental Protection Agency, and are almost 30 times higher than the World Health Organization's target guideline for outdoor PM2.5 concentrations. The article by Goodman and colleagues adds to the irrefutable body of evidence showing that smoke-free air policies improve air quality, save lives, improve health, and are cost-effective and popular.
Roswell Park Cancer Institute
University of Kentucky FOOTNOTES Conflict of Interest Statement: Neither author has a financial relationship with a commercial entity that has an interest in the subject of this manuscript. REFERENCES
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