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Airborne hazards are potentially toxic substances that a person is exposed to when breathing air. These hazards may be dusts, particles, fibers, mists, vapors, fumes or gases.

Exposure to airborne hazards can occur in the home (indoor air exposures), in the workplace (occupational exposures), or outdoors in the community (environmental exposures). Breathing in toxic substances can increase a person’s risk of health conditions ranging from asthma and other lung conditions to cardiovascular disease and certain cancers. 

“Since everyone breathes in toxic substances in the air, everyone is at some risk of health effects that might be associated with these airborne exposures,” says Dr. Jesse Monestersky, an occupational and environmental medicine physician with Defense Health Agency-Public Health in Aberdeen, Maryland.

What are examples of airborne hazards? 

The Environmental Protection Agency, Occupational Safety and Health Administration, and the Veterans Administration have identified airborne hazards from both indoor and outdoor sources, routine day-to-day habits and living conditions, workplace and military activities, and certain unique environmental events. Examples include— 

Indoor exposures:  

  • Combustion products (heating fuels)  
  • Direct or secondhand tobacco and vaping smoke  
  • Off-gassing from carpets and upholstery/furniture 
  • Cleaning products  
  • Toxins from molds 
  • Radon 

Workplace exposures: 

  • Toxic chemicals (various industrial operations, combustion fuels, painting, plastics) 
  • Abrasion (sanding, grinding, polishing, abrasive blasting)  
  • Fibers (asbestos, fiberglass) 
  • Hot processes (welding, furnaces, soldering, brazing) 

Outdoor exposures: 

  • Air pollutants and smog  
  • Wildland forest fires 
  • Natural disaster events (volcanic ash, sandstorms) 

Military exposures: 

  • Smoke and fumes from open-air burn pits  
  • Sand, dust and particulate matter  
  • Air pollution (worse in certain foreign countries and certain locales)  
  • Motor vehicle, aircraft and industrial machinery engine exhaust  
  • Smoke from burning oil wells 
  • Munitions, bullets and explosives smoke   
  • Chemical hazards in the air (e.g., pesticides, defoliants) 

Who is at risk? 

“Whether or not a person develops certain illnesses from airborne hazard exposures depends on the types and amounts of substances exposed and underlying medical conditions, in addition to risky social habits such as smoking or vaping,” says Monestersky. 

He says the risk of developing an illness may increase if a person is exposed to multiple types of airborne hazards over extended periods of time or from an extremely high single exposure to certain toxics.

How do scientists decide if an illness is caused by an airborne hazard? 

“It is often difficult to scientifically show a causal link between a single type or source of exposure and an illness,” says Monestersky.  

He explains that to determine a relationship between an exposure or exposures and one or more illnesses, experts typically consider multiple scientific studies, including toxicological laboratory studies involving animals and epidemiological evaluations of human populations. 

“Even when high doses of a toxic substance show an adverse effect in a laboratory experiment, the real-life exposures are hard to replicate. It’s a basic toxicological principle that ‘the dose makes the poison,’ so we need to determine the amount of a substance or substances a person was exposed to determine a likely impact on human health,” says Monestersky.  

Monestersky says sometimes the delay between the development of a disease and the various possible exposures can complicate the understanding of any association. 

“The onset of illness may occur years after exposures,” says Monestersky. “The big picture view of the exposure data and disease provides the scientific weight-of the-evidence.” 

Monestersky explains this “weight-of-the-evidence” standard may not be sufficient to show a causal connection between an airborne hazard exposure and a specific illness, but it may indicate that one cannot reasonably rule out the possibility of a relationship. 

“As a result, certain health conditions may be considered presumptively connected to a military exposure,” says Monestersky. 

What are presumptive health conditions? 

Regardless of your personal risk factors, identified presumptive health conditions are automatically considered to be connected to a service-related exposure that occurred at a specific time and deployment location. 

With the passage of the 2022 Promise to Address Comprehensive Toxics, or PACT Act, the Veterans Administration automatically presumes that certain presumptive conditions were caused by military service. This takes the burden of proof off the veteran or service member.  

Many presumptive conditions are associated with airborne hazard exposures that occurred during the Gulf War era and post-9/11, including several Southwest Asia deployments such as to Iraq, Afghanistan or Kuwait. 

Presumptive conditions associated with toxic exposures, including those from airborne hazards currently listed under the PACT Act, include those in Table 1:

Presumptive health conditions currently listed under the PACT Act. (Photo by Douglas Holl)

How are service members’ exposures to military-related airborne hazards being addressed? 

For many years, medical and public health experts from the Department of Defense and the VA have studied airborne hazards related to military activities to accomplish the following: 

  • Identify exposures of concern,  
  • Establish measures to prevent or reduce future exposures, and 
  • Ensure medical and VA disability compensation and access to VA medical care are provided to uniformed personnel with military environmental exposures. 

The VA oversees several military environmental health registries including the Airborne Hazards and Open Burn Pit Registry and the Gulf War Registry. Registry medical exams are provided under each program. The exams, which are independent of the VA benefits process, provide patients with insight on their health and an opportunity to have their concerns addressed. Medical findings also provide VA and DOD researchers data to analyze and guide care for service members and veterans. 

What can service members and veterans do?   

Monestersky recommends that service members and veterans take the following actions: 

1. Identify and document your exposure history. 

  • Review the information posted by the DOD and VA that provides important resources about airborne hazards. This information provides knowledge on health effects of possible past exposures, and relevant disease registries. It can also help frame questions to discuss with your healthcare providers. 
  • Access the Periodic Occupational and Environmental Monitoring Summary (POEMS) publicly available deployment website site for information on possible exposures for specified times at select deployment sites. POEMS summarize risk of potential health effects to service members (they do not address individuals' unique exposures).  
  • Express your concerns about possible occupational and environmental exposures in the Periodic Health Assessment electronic self-assessments that include the annual, PHA, Pre- and Post-Deployment Health Assessment, or PDHA, and Post-Deployment Health Reassessment, known as the PDHRA.
  • Discuss any exposures with your healthcare provider and ask your healthcare provider to have these exposure concerns documented in your electronic medical record.

2. Take steps to reduce your risk of illness by following a healthy lifestyle and reducing personal risk factors.

  • Maintain a healthy lifestyle (nutritious food, weight management, physical fitness)
  • Eliminate harmful habits such as smoking or vaping
  • Optimize the medical management of underlying chronic medical conditions with your healthcare provider 
  • Use personal protective equipment as appropriate
  • Ensure good ventilation in your home 
  • Avoid outdoor running and aggressive workouts when outdoor air quality is poor

Additional information sources:

Department of Defense: 

Department of Veterans Affairs: