Air Quality & Ionizing Radiation

Air Quality

Although air pollution has decreased in many parts of the world, it represents a significant and growing health problem for the residents of some cities in certain industrializing countries. Polluted air can be difficult or impossible for travelers to avoid, and the risk to otherwise healthy people who have only limited exposure is generally low. Conversely, those with preexisting heart and lung disease, children, and older adults have an increased risk of adverse health effects from even short-term exposure to air pollution.

Travelers, particularly those with underlying cardiorespiratory disease, should be familiar with the air quality at their destination. The AirNow website (http://airnow.gov) provides basic information about local air quality using the Air Quality Index (AQI) (Table 3-1). The World Air Quality Index project shows real-time air quality/air pollution data for more than 10,000 air stations in more than 80 countries around the world (https://waqi.info/) and the World Health Organization posts historical data on outdoor air pollution in urban areas at http://gamapserver.who.int/gho/interactive_charts/phe/oap_exposure/atlas.h....

Table 3-1. Air quality index
Air Quality Index Levels of Health Concern	Air Quality Index Values	Meaning
Good	0 to 50	Satisfactory air quality Air pollution poses little or no risk
Moderate	51 to 100	Acceptable air quality Some pollutants may represent a moderate health concern for highly sensitive people
Unhealthy for Sensitive Groups	101 to 150	Members of sensitive groups may experience health effects General public not likely to be affected
Unhealthy	151 to 200	Everyone may begin to experience health effects Sensitive groups may experience more serious health effects
Very Unhealthy	201 to 300	Health alert: everyone may experience more serious health effects
Hazardous	301 to 500	Health warnings of emergency conditions Entire population is more likely to be affected
Air Quality Index Basics. [cited 2018 Jan 22]. Available from: www.airnow.gov/index.cfm?action=aqibasics.aqi.

Travelers should be mindful of, and limit exposures to, indoor air pollution and carbon monoxide (Table 3-2). Secondhand smoke from smoking tobacco is an important contributor to indoor air pollution. Other potential sources of indoor air pollutants include cooking or combustion sources, such as kerosene, coal, wood, or animal dung. Major sources of indoor carbon monoxide include gas ranges and ovens, unvented gas or kerosene space heaters, and coal- or wood-burning stoves. Ceremonial incense and candles are often unrecognized asthma triggers.

Table 3-2. Strategies to mitigate adverse health effects of air pollution
Environmental Source	Pollutants	Traveler Category	Mitigation Strategies
Outdoor air	Poor air quality (high levels of air pollution) or areas potentially affected by wildland fires	Travelers with preexisting asthma, chronic obstructive pulmonary disease, heart disease	Limit strenuous or prolonged outdoor activity
Outdoor air		All travelers	Facemasks (decision to wear should be left to the traveler) ¹
Indoor air	High levels of smoke (for example, from cooking and combustion sources, tobacco, incense, and candles)	Long-term travelers and expatriates	Consider purchasing indoor air filtration system
Indoor air		All travelers	Avoidance
¹ CDC has no recommendations regarding facemask use for travelers. One small study in Beijing showed that wearing a dust respirator with valves appeared to mitigate the negative health effects of air pollution on blood pressure and heart rate. However, the respirators used in the study had better filtration than the surgical or nuisance dust masks commonly worn in some countries.

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