Environmental Hazards


Air pollution has decreased in many parts of the world, but it is worsening in certain industrializing countries. Polluted air can be difficult or impossible to avoid, but the risk to healthy short-term travelers is most likely low. People with preexisting heart and lung disease, children, and older adults are at higher risk.

Travelers should be familiar with the air quality at their destination. The AirNow website (http://airnow.gov/) provides information about the effects of particulate matter and ozone, as well as links to international air quality sites. Historical data on outdoor air pollution in urban areas are available from the World Health Organization at http://gamapserver.who.int/gho/interactive_charts/phe/oap_exposure/atlas.h....

Travelers should also limit exposure to indoor air pollution and carbon monoxide. Possible 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. Another important source of indoor air pollution is secondhand smoke produced from smoking tobacco.

Travelers to countries where air pollution may be a problem should consider the following:

  • For people with preexisting conditions such as asthma, chronic obstructive pulmonary disease, and heart disease, limit strenuous or prolonged outdoor activity, particularly in cities.
  • For long-term travelers and expatriates, consider investing in an indoor air filtration system.
  • Avoid indoor areas with high levels of indoor air pollutants such as tobacco smoke. For additional information on tobacco laws and smoke-free places in 201 countries, visit www.tobaccocontrollaws.org/legislation.
  • As much as possible, look for lodging with working smoke and carbon monoxide detectors.

Travelers to areas where air pollution is reported to be high might inquire about the advisability of wearing face masks. CDC has no recommendations regarding the use of face masks for travelers. One small study in Beijing showed that wearing a valved dust respirator appeared to mitigate the effects of air pollution on blood pressure and heart rate. However, it should be noted that the respirators used in the study had better filtration than the surgical masks commonly worn in some countries. The decision to wear a mask should be left to the traveler’s discretion.

Mold Contamination

Extensive water damage after hurricanes or floods can lead to mold contamination in buildings. Travelers may visit flooded areas overseas as part of emergency, medical, or humanitarian missions. Mold is a more serious health hazard for people who are immunocompromised or have respiratory problems. To prevent exposure that could result in adverse health effects from disturbed mold, people should adhere to the following recommendations:

  • Avoid areas where mold contamination is obvious.
  • If the traveler will be working in a moldy environment (such as on a medical or humanitarian mission), use personal protective equipment (PPE), such as gloves, goggles, and a fit-tested N95 respirator or higher. These travelers should take sufficient PPE with them, as these may be scarce in the countries visited.
  • Keep hands, skin, and eyes clean and free from mold-contaminated dust.
  • Review the CDC guidance, Mold Prevention Strategies and Possible Health Effects in the Aftermath of Hurricanes and Major Floods (www.cdc.gov/mmwr/preview/mmwrhtml/rr5508a1.htm), which provides recommendations for dealing with mold in these settings.


Natural background radiation levels can vary substantially from region to region, but these variations are not a health concern. Travelers should be aware of regions known to have been contaminated with radioactive materials, such as the areas surrounding the Chernobyl nuclear power plant in Ukraine and the Fukushima Daiichi nuclear power plant in Japan.

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, and 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. For up-to-date information or any travel advisories, see the Department of State’s information for Japan (http://travel.state.gov/content/passports/english/country/japan.html).

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, however, 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 also 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 tri-foil symbol or other radiation signs (see www.remm.nlm.gov/radsign.htm for examples). Travelers who encounter a questionable object should not touch or move the object and should notify local authorities.


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Armin Ansari, Suzanne Beavers