Estimated reading time: 12 minutes
Though outdoor physical activity has many health benefits, exposure to air pollution can cause negative health effects, including increased cardiovascular disease risk. Everyone, including athletes, should use the air quality index (AQI) to plan their outdoor activities and protect their health.
This article explains how high air pollution may influence your health and offers tips for staying physically active without risking exposure to air pollution.
The Link Between Air Pollution and Physical Activity
While public perception focuses on how insufficient physical activity can lead to poor health outcomes, fewer people discuss how outdoor physical activity in polluted environmental conditions can also impact health.
The relationship between air pollution and physical activity has been extensively studied in human and animal studies. The World Health Organization notes that 4.2 million deaths are attributed to ambient air pollution, with the majority of deaths in developing countries.
Of these deaths, 69% were due to ischemic heart disease and stroke, 14% were due to chronic obstructive pulmonary disease (COPD), 14% were due to acute lower respiratory infections, and 4% were due to cancer.
Multiple air pollutants, such as PM2.5, nitrogen dioxide, and ozone, have combined effects on the cardiovascular system. PM2.5 can decrease lung function, while long-term exposure to nitrogen dioxide can lead to decreased cognitive function and systemic inflammation. Though ozone is typically discussed in terms of environmental science, it also damages the airways and can lead to lung infections.
Why Exercising in Polluted Air Poses Higher Risks
Aerobic exercise, like running or biking, leads to increased breathing frequency. This means that those who exercise outdoors inhale more air pollutants than those who stay inside. Fine particulate matter enters the respiratory system and, ultimately, the bloodstream. This can impact cardiovascular health, especially with long-term exposure to highly polluted air.
Short-term effects of air pollution exposure can include shortness of breath, wheezing, watering eyes, sore throat, and coughing. These can be especially dangerous for people with asthma, an active respiratory infection, or cardiovascular issues like heart disease or heart defects.
Over the long term, ambient air pollution can cause serious harm to nearly every part of the body, but especially to the heart and lungs.
Rats exposed to air pollution developed respiratory lesions, which compromised their lung tissue. Cardiovascular research demonstrates how lung problems contribute to heart disease, meaning the effects of air pollution can linger long after the air has cleared.
Particular matter impacts skeletal muscle, including higher inflammation, both during periods of physical inactivity and during exercise. These adverse effects mean that muscles will stay sore for longer and may not rebuild as quickly, reducing the beneficial effects of things like bodyweight exercises.
While playing outside is a great use of a child’s leisure time, physical activity may also lead to serious effects down the line. Environmental research has found a positive association between air pollution and poor mental health in children and young adults, as their developing brains are more sensitive. As global climate change continues to reduce air quality, there may be a global burden of serious psychiatric issues.
Understanding AQI and Its Impact on Exercise Safety
The Environmental Protection Agency (EPA) regulates certain forms of air pollution. These are monitored across the United States and used to generate the Air Quality Index (AQI). The AQI assesses the parts per million (ppm) of different pollution types, then categorizes them based on the risk they pose to people. The different categories are as follows:
- 0-50 ppm (Good): Air quality is good. There is little or no risk to public health.
- 51-100 ppm (Moderate): There is a moderate risk. Very sensitive individuals, like those with serious immune disorders or COPD, may experience adverse effects.
- 101-150 ppm (Unhealthy for Sensitive Individuals): Pregnant women, children, people with cardiovascular disease, and the elderly should take extra precautions.
- 151-200 (Unhealthy): The air quality is unhealthy for everyone, including the general public. Members of sensitive groups will experience serious health risks.
- 201-300 (Very Unhealthy): Air quality is very unhealthy for everyone, no matter their health level. If possible, stay indoors entirely.
- 301 and above (Emergency): This represents an air pollution emergency with serious risks to human health. Physical exercise is inadvisable even when indoors.
By considering AQI and exercise safety, you can ensure you get all the benefits of exercise without putting yourself in danger.
What AQI Levels Mean for Your Workout
New York State has provided a helpful guide to what activities to consider at each AQI level.
- 0-50 ppm (Good): Outdoor exercise is safe for everyone, even vulnerable individuals. This is a good time for high-intensity exercise or long workouts.
- 51-100 ppm (Moderate): Air quality is good for most people, though particularly sensitive individuals may want to reduce their physical activity or cut their workout short.
- 101-150 ppm (Unhealthy for Sensitive Individuals): People with underlying health conditions will want to avoid exercising for more than one hour outdoors. Others should monitor any symptoms and take a break if they experience shortness of breath or watering eyes.
- 151-200 (Unhealthy): When air quality is poor, any outdoor activities should be limited to less than one hour. Sports events should be rescheduled, and sensitive individuals should limit time outside.
- 201-300 (Very Unhealthy): Everyone should avoid unnecessary time outside, especially physical activity. Move all exercise indoors.
- 301 and above (Emergency): Air pollution greatly exceeds safe levels. Even with proper precautions, pollutants may still enter indoor spaces and cause health issues. Consider reducing activity and rescheduling events.
Where to Check Real-Time AQI Data
One of the best places to check the Air Quality Index is AirNow, run by the EPA. You can access their resources through the website or their mobile app. AirNow also provides an API that developers and fitness platforms can incorporate into their fitness tracking apps or websites, helping athletes make informed decisions about outdoor exercise.
Other options include air quality apps such as AirVisual, which provides real-time air quality updates.
Visual Crossing’s Timeline Weather API provides both air quality data and key weather variables, such as temperature, wind speed, and wind direction, enabling developers, fitness enthusiasts, and sports teams to anticipate changes in pollution levels and take proactive steps to stay safe.
For example, temperature and wind speed can all influence pollution patterns, meaning you can use algorithms to predict where particular matter may land in the next few hours or days.
Who Is Most Vulnerable When Exercising in Polluted Air?
While air pollution is dangerous for everyone, it poses additional risks to certain groups. Children, the elderly, pregnant women, people with asthma or COPD, and people with cardiovascular disease are at increased risk. Additionally, outdoor workers must be especially cautious because they often experience long-term exposure.
Air pollution sensitivity varies from person to person depending on underlying health conditions, age, and general fitness. Everyone should pay attention to the AQI when they expect to be outdoors for longer periods. While outside, monitor your symptoms and make informed decisions about whether the benefits of outdoor exercise outweigh the risks.
Best Practices for Safe Outdoor Exercise in Poor Air Quality
It’s possible to enjoy safe exercise in polluted air as long as you are aware of the risks and take appropriate precautions. Consider these tips to ensure that you can stay active without endangering your health.
Time Your Workouts Wisely
Generally, pollution risks are lower in the early mornings and late evenings. Ozone is particularly susceptible to temperature, as high temperatures increase the frequency of the chemical reactions that cause it. As the temperature is lower in the morning and evening, the pollution is less intense and the air is safer.
Additionally, there are usually fewer cars on the roads, and factories may not be at full production capacity. All these contribute to the air quality. Consider going for a run in the morning before work or riding your bike in the evening, after the temperature has dropped. Always remember to wear high-visibility safety gear.
You can check hourly AQI forecasts using Visual Crossing’s Timeline Weather API, which includes key air quality metrics such as the U.S. AQI (aqius), PM2.5, ozone, and more. These forecasts help you assess potential pollution risks throughout the day so you can plan your workout more safely.
Combined with additional data like temperature, humidity, and wind speed—all available from the same API—you can better understand how environmental conditions may amplify the effects of air pollution during exercise.
Choose the Right Locations
Always avoid exercising near traffic-heavy roads like highways and industrial areas, as these are major sources of air pollution. Instead, try green spaces, parks, and trails that are protected from potential pollution sources. Plants, like trees and grasses, help filter the air and protect you from these health dangers.
Adjust Intensity and Duration
When pollution is high, choose a lighter workout or shorten your time outdoors. For example, if you usually go for a three-mile run during your workout, consider choosing a shorter trail and following it up with a different activity, like weight training. You could also choose to go for a walk instead.
Consider Indoor Alternatives
Consider an indoor workout when the air quality is poor. Gyms can be a great way to mimic outdoor activities, such as using a treadmill or a gazelle machine. You could also try virtual fitness classes and bodyweight exercises in the comfort of your own home.
There can be benefits to changing up your routine, too. As different workouts focus on other muscles, you may become a more balanced athlete overall by varying the intensity and type of workouts you perform. Consider going for a swim at an indoor pool instead of running, biking, or hiking. You could also do drop-in fitness classes at your local gym to try something new.
If air pollution is at extremely hazardous levels, you should shorten your workout entirely, even if you are indoors. Tiny particulates can enter through cracks in windows, doorjambs, and ventilation shafts, leading to stubborn indoor pollution. You may still be at risk when performing vigorous physical activities.
Using Technology to Support Air-Quality-Aware Fitness
By combining weather APIs and air quality data, you can make safer decisions while still enjoying the many benefits of being outdoors. Consider using apps or wearables that incorporate AQI monitoring and provide alerts when air quality is low.
Developers can use Visual Crossing’s weather APIs to build fitness tools with real-time air quality measures, tapping into the fitness market while also protecting human health.
Fitness Apps That Use Air Quality Data
There is a growing demand for personalized fitness applications that also consider environmental data, like air quality. One of the most well-known is AirTrack by Air Aware Labs, which incorporates air pollution into fitness tracking.
AirTrack provides real-time maps, suggests the best times to work out, and warns users about potentially dangerous air quality. The app supports over 110,000 different activities, from hiking to yardwork, so you can always be on top of your fitness.
Visual Crossing’s Role in Data-Driven Fitness
Visual Crossing’s API provides both hyperlocal air quality data—including U.S. AQI values—and detailed environmental metrics like temperature, humidity, and wind speed. This combination is especially valuable for fitness enthusiasts who want to plan safe and effective workouts.
By reviewing current and forecasted conditions in one platform, you can make informed choices about when and where to train outdoors based on pollution levels and how the weather may influence them.
Special Considerations for Athletes, Coaches, and Trainers
Sports professionals face competing interests: they need to train for competitions and events, but they also need to protect their health for the long term. Coaches and sports teams also need to consider the long-term costs of rescheduling events or canceling practices.
Teams and training programs should integrate air quality data into their routines. Before planning outdoor training events, check the AQI and determine whether it is generally safe for athletes. If necessary, adjust practice schedules and hold sessions inside instead.
During events, teams should consider whether the current AQI could pose a risk to spectators, such as children and the elderly. Additionally, potential air pollution effects should be incorporated into athlete health assessments, as cardiovascular function is crucial to good performance.
Long-Term Health Considerations and Prevention Strategies
When considering the health risks of physical activity and air pollution, we must consider incidence risk. Short-term exposure to high air pollution levels, such as what many Americans experienced during the 2023 Canadian wildfires, is dangerous but may not result in long-term serious harm.
However, regular vigorous-intensity physical activity in highly polluted areas is a major contributor to coronary heart disease, lung disease, and premature death.
Regular physical activity in clean air can have anti-inflammatory effects, but this isn’t true when people work out in polluted areas.
Columbia University Medical Center’s research found that decades of air pollution damaged immune cells in the lungs, leading to an increased risk of respiratory infections. Respiratory issues increase blood pressure and can cause hypertension, increasing the risk of cardiovascular disease or stroke.
Encouraging a Culture of Awareness and Responsibility
Air quality affects everyone, but it is especially crucial for sensitive individuals and those who spend significant time outdoors. Each of us can be an ambassador who shares vital, science-based information about the relationship between air pollution and physical activity.
For example, runners might suggest changing routines with their running group on days with a poor AQI rating, while physical education teachers can share details about how air quality can influence children’s feelings and performance.
Social media is also a great way to increase awareness about this important topic. Share quality, peer-reviewed resources about air quality with your social group and encourage others to take precautions on high-pollution days.
By making good choices, we can help our whole community avoid the dangerous effects of air pollution, leading to a healthier society overall. Combining personal fitness with respect for the environment can also raise awareness about climate change, pollution, and public health.
Conclusion: Move Your Body, Protect Your Health
Physical activity is essential for looking and feeling good. Spending time outdoors helps us connect to nature, improves mood, and reduces stress. However, being aware of air pollution ensures that we are making the best choices for our bodies in the long term.
You don’t have to choose between staying fit and staying safe if you remain mindful of the dangers and are willing to be flexible about your fitness routine. Monitoring ambient air pollution lets you make smart choices about when to stay inside and when to hit the trails. With the correct tools, timing, and knowledge, everyone can find the right balance between their overall health and their time spent outdoors.
Visual Crossing’s Timeline Weather API provides up-to-date weather information from high-quality government sources. When integrated with other data, like the EPA’s air quality index, it can help people plan their fitness routines while being conscious of the potential danger.
Fitness app developers should consider providing more data for their clients by combining our API with air quality details. This way, everyone can make choices that support their long-term health while still enjoying the great outdoors.