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 ( 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 ( and the World Health Organization posts historical data on outdoor air pollution in urban areas at

Table 3-1. Air quality index

Air Quality Index Levels of Health Concern

Air Quality Index Values



0 to 50

Satisfactory air quality

Air pollution poses little or no risk


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


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


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:

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


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

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

All travelers


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.


Travelers may visit flooded areas as part of emergency, medical, or humanitarian relief missions. Water damage to buildings can lead to mold contamination. Mold is a more serious health hazard for the immunocompromised or for people who have respiratory problems such as asthma. To prevent exposures that could result in adverse health effects, travelers should adhere to the following recommendations:

  • Avoid areas where mold contamination is obvious.
  • When working in moldy environments, use personal protective equipment (PPE), such as gloves, goggles, and a NIOSH-approved N95 respirator or higher. To learn more about mold and respirators, visit Travelers should anticipate needing to bring sufficient quantities of PPE with them, as supplies may be scarce or not available in the countries visited.
  • Keep hands, skin, and eyes clean and free from mold-contaminated dust.
  • Review recommendations for dealing with mold:


Background radiation levels can vary substantially from region to region, but these variations are natural and do not represent a health concern. In addition, several regions in the world have high natural background radiation. Examples of these areas include Guarapari (Brazil), Kerala (India), Ramsar (Iran), and Yangjiang (China), and traveling to these areas does not pose a threat to health. By contrast, travelers should be aware of (and avoid) regions known to be contaminated with radioactive materials. Areas surrounding the Chernobyl nuclear power plant in Ukraine and the Fukushima Daiichi nuclear power plant in Japan, for example, have radiation levels that greatly exceed background and represent a significant risk to health and safety.

The Chernobyl plant is located 100 km (62 miles) northwest of Kiev. The 1986 accident contaminated regions in 3 republics—Ukraine, Belarus, and Russia—but the highest radioactive ground contamination is within 30 km (19 miles) of Chernobyl.

The Fukushima Daiichi plant is located 240 km (150 miles) north of Tokyo. After the accident in 2011, the area within a 20-km (32-mile) radius of the plant was evacuated: Japanese authorities also advised evacuation from locations farther away to the northwest of the plant. As Japanese authorities continue to clean the affected areas and monitor the situation, access requirements and travel advisories change. The Department of State recommends against all unnecessary travel to areas designated by the Japanese government as restricted because of radioactive contamination. For up-to-date safety information or current travel advisories for any country, see the Department of State’s website ( or check with the US mission in that country.

In most countries, areas of known radioactive contamination are fenced or marked with signs. Any traveler seeking long-term (more than a few months) residence near a known or suspected contaminated area should consult with staff of the nearest US embassy and inquire about any advisories regarding drinking water quality or purchase of meat, fruit, and vegetables from local farmers.

Radiation emergencies are rare events. In case of such an emergency, travelers should follow instructions provided by local authorities. If such information is not forthcoming, US travelers should seek advice from the nearest US embassy or consulate.

Natural disasters (such as floods) may displace industrial or clinical radioactive sources. In all circumstances, travelers should exercise caution when they encounter unknown objects or equipment, especially if they bear the basic radiation trefoil symbol or other radiation signs (see for examples). Travelers who encounter a questionable object should avoid touching or moving it, and notify local authorities as quickly as possible.


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Armin Ansari, Suzanne Beavers