Indoor Air Quality at Nine Large-Hub Airports With and Without Designated Smoking Areas — United States, October–November 2012

On November 20, 2012, this report was posted as an MMWR Early Release on the MMWR website (http://www.cdc.gov/mmwr).

Secondhand smoke (SHS) exposure causes death and disease among nonsmoking adults and children (1). Adopting policies that completely prohibit smoking in all indoor areas is the only effective way to eliminate involuntary SHS exposure (1). Among the 29 large-hub U.S. airports, five currently allow smoking in specifically designated indoor areas accessible to the general public (2). In 2011, these five airports had a combined passenger boarding of approximately 110 million (3). To assess indoor air quality at the five large-hub U.S. airports with designated indoor smoking areas and compare it with the indoor air quality at four large-hub U.S. airports that prohibit smoking in all indoor areas, CDC measured the levels of respirable suspended particulates (RSPs), a marker for SHS. The results of this assessment determined that the average level of RSPs in the smoking-permitted areas of these five airports was 16 times the average level in nonsmoking areas (boarding gate seating sections) and 23 times the average level of RSPs in the smoke-free airports. The average RSP level in areas adjacent to the smoking-permitted areas was four times the average level in nonsmoking areas of the five airports with designated smoking areas and five times the average level in smoke-free airports. Smoke-free policies at the state, local, or airport authority levels can eliminate involuntary exposure to SHS inside airports and protect employees and travelers of all ages from SHS.

Large-hub airports are defined by the Federal Aviation Administration as airports that accounted for ≥1% of total passenger boarding in the United States during the previous year (3). This study included five large-hub U.S. airports with designated smoking areas accessible to the public*: Denver International, Hartsfield-Jackson Atlanta International, McCarran International in Las Vegas, Salt Lake City International, and Washington Dulles International (2). Four smoke-free (i.e., smoking prohibited in all indoor areas at all times) large-hub airports with similar passenger boarding totals in 2011 were selected for comparison: Chicago O'Hare International, Fort Lauderdale-Hollywood International, Orlando International, and Phoenix Sky Harbor International.

The specific class of RSPs monitored was particulate matter ≤2.5 microns in diameter (PM2.5), a commonly used marker for SHS (4,5) Particles of this size are released in substantial amounts from burning cigarettes and easily inhaled deep into the lungs. The final sample consisted of 45 sites in airports with designated smoking areas and four sites in smoke-free airports. Overall, in the five airports with designated smoking areas, PM2.5 levels were measured 1) inside 20 smoking-permitted areas, 2) approximately 1 meter (3.3 feet) adjacent to each of the 20 smoking-permitted areas, and 3) in the seating sections at five randomly selected boarding gates where smoking was not allowed. PM2.5 levels were measured at one randomly selected gate in each of the four smoke-free airports. Adjacent areas were included in the study to assess whether SHS leaked from smoking-permitted areas. Smoking-permitted areas were subcategorized as smoking rooms, bars, or restaurants and also subcategorized as fully enclosed or partially enclosed.

Data were collected during October 19–November 1, 2012, by one person during 1 day at each airport between the hours of 7 a.m. and 11 p.m. The median time spent at each site was 30 minutes (range: 20–90 minutes). An air monitor† was used to log PM2.5 at 1-minute intervals, using a calibration factor of 0.32 and a flow rate of 1.7 L/min (4). The first and last 1-minute measurements were discarded, and the remaining data points were averaged to compute the mean PM2.5 level at each site. Data on 5-minute interval counts of the number of persons and the number of burning cigarettes in each smoking-permitted area also were collected. Sampling was conducted discreetly in order not to alter the occupants' smoking behavior. Smoker density was calculated by dividing the average number of burning cigarettes by the estimated room volume and expressed as the number of burning cigarettes per 100 m3. Spearman's correlation coefficient (ρ) was calculated to assess the relationship between smoker density and PM2.5 (p<0.05). A two-sample t-test was conducted to assess the statistical significance of differences between average PM2.5 levels (p<0.05).

The overall average PM2.5 level in smoking-permitted areas was 188.7 µg/m3 (range: 29.1–555.3), and the average PM2.5 level in areas adjacent to smoking-permitted areas was 43.7 µg/m3 (range: 2.1–230.0). The average PM2.5 level in nonsmoking areas of airports with designated smoking areas was 11.5µg/m3 (range: 2.2–29.0), and the average PM2.5 level in smoke-free airports was 8.0 µg/m3 (range: 2.0–15.2). The difference between the average level in the nonsmoking areas of airports with designated smoking areas and the average level in smoke-free airports was not statistically significant (Table, Figure 1).

The average PM2.5 level in the four smoking-permitted bars and restaurants was 276.9 µg/m3 (range: 73.5–555.3), whereas the average PM2.5 level in the 16 smoking rooms was 166.6 µg/m3 (range: 29.1–382.3). The median of the average number of persons in smoking-permitted areas was 9.3 (range: 2.7–101.7). The median of the average number of burning cigarettes was 7.2 (range: 2.8–56.3) (Table).

The average PM2.5 level in areas adjacent to partially enclosed smoking-permitted areas (82.5 µg/m3) was higher than the average PM2.5 in areas adjacent to fully enclosed smoking-permitted areas (30.8 µg/m3) (p<0.05). Smoker density was strongly correlated with PM2.5 (ρ=0.81, p<0.05) (Figure 2).

Reported by

Brian King, PhD, Michael Tynan, Gabbi Promoff, MA, Steve Babb, MPH, Office on Smoking and Health, National Center for Chronic Disease Prevention and Health Promotion; Jonetta L. Johnson, PhD, Israel Agaku, DMD, EIS officers, CDC. Corresponding contributor: Israel Agaku, iagaku@cdc.gov, 770-488-5138.

Editorial Note

The findings in this report indicate that workers and travelers, including children and adults, are at risk for exposure to SHS in airports with designated smoking areas. These findings are consistent with previous research that found elevated PM2.5 levels in areas adjacent to enclosed smoking-permitted areas in a medium-hub airport (6). There is no risk-free level of SHS exposure; even brief exposures can have immediate adverse effects on the cardiovascular and respiratory systems (1,7).

Although smoking was prohibited on all U.S. domestic and international commercial airline flights through a series of federal laws adopted from 1988 to 2000, no federal law or policy requires airports to be smoke-free. Certain tobacco product manufacturers have promoted and paid for separately enclosed and ventilated smoking areas in airports and have opposed efforts to implement smoke-free policies in airports (8). Most airports with designated smoking areas are explicitly exempted from state smoke-free laws or are located in states without comprehensive smoke-free laws. For example, although state laws in Colorado§ and Utah¶ prohibit smoking in indoor areas of workplaces and public places, they specifically allow designated smoking areas at airports.

Because the duration of air monitoring in each location was approximately 30 minutes, the observed PM2.5 levels cannot be compared directly to current U.S. Environmental Protection Agency average 24-hour and annual PM2.5 exposure standards (35 µg/m3 and 15 µg/m3, respectively) (9). However, given that the average PM2.5 level in smoking-permitted bars and restaurants was 24 times the average level in nonsmoking areas of the same airports (276.9 µg/m3 versus 11.5 µg/m3), workers in smoking-permitted areas such as bars and restaurants might be at heightened risk for SHS exposure and related health problems (9,10).

The findings in this report are subject to at least three limitations. First, SHS is not the only source of PM2.5, and PM2.5 levels can vary from airport to airport because of differences in elevation above sea level. However, although ambient particle concentrations and cooking are additional sources of PM2.5, SHS is the largest contributor to PM2.5 levels in indoor settings where smoking is allowed (5). Second, PM2.5 levels inside and adjacent to the smoking-permitted areas were not measured simultaneously, so it was not possible to assess SHS leakage into smoking-restricted areas in real time. Finally, in very large smoking-permitted areas, the inability to count the exact numbers of occupants and burning cigarettes might have resulted in imprecise estimates.

Both employees and travelers at airports with designated smoking areas could be at risk for SHS exposure. For example, travelers who do not enter smoking-permitted areas can be exposed to SHS in adjacent areas. Employees who work in smoking-permitted restaurants and bars, or who are required to enter smoking-permitted areas for cleaning, maintenance, or other reasons, also are at risk for SHS exposure. In addition, children who are allowed to enter or wait near smoking-permitted areas might be at risk for SHS exposure. Completely eliminating smoking inside airports is the only way to eliminate SHS exposure for nonsmoking workers and travelers of all ages (1).

Acknowledgments

Kenneth Ray, MPH, Tobacco Use Prevention Program, Div of Public Health, Georgia Dept of Human Resources. Cherie Drenzek, DVM, Georgia Dept of Public Health. Courtney Ward, MPA, Bur of Tobacco and Chronic Disease; Kenneth Komatsu, MPH, Arizona Dept of Health Svcs. Jill Bednarek, MSW, Lisa Miller, MD, Colorado Dept of Public Health and Environment. Gregg Smith, Bur of Tobacco Free Florida; Carina Blackmore, DVM, PhD, Florida Dept of Health. Conny Moody, MBA, Gail De Vito, MPA, Office of Health Promotion, Illinois Dept of Public Health. Patricia Rowley, Office of Epidemiology, Southern Nevada Health District; Karla Bee, MPH, Tobacco Program; Ihsan Azzam, MD, PhD, Nevada Dept of Health and Human Svcs. Janae Duncan, MPA, Tobacco Prevention and Control Program; Robert Rolfs, MD, Utah Dept of Health. Myra Shook, MPH, Karen Ramley, MD, David Trump, MD, Virginia Dept of Health. Constantine Vardavas, MD, PhD, Harvard School of Public Health, Boston, Massachusetts. Joanna Watson, DPhil, EIS Officer, CDC.

References

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