Getting in shape can have a positive impact on your health. 30 minutes of exercise a day reduces your risk of developing many conditions like heart disease and lung cancer.1,2
But exercising in polluted air can have the opposite effect. You take more air into your lungs when you’re active than when you are inactive. If air quality is poor, you can breathe in dangerously high levels of harmful, even deadly, pollutants.3,4
Air quality monitoring and forecasting can help you optimize when and where you’ll get the most outdoor exercise benefits.
How do I incorporate air quality forecasting into my workout?
Air quality changes quickly: the number of pollutants in your neighborhood when you wake up in the morning can spike in mere minutes during rush hour. Travel just a few miles away from that busy street or highway, and pollutant concentrations can drop to undetectable levels. You can always tune into the news or check a forecast online to plan a workout around high temperatures or rain. But it can feel challenging to plan outdoor workouts when so many factors contribute to pollution.
Air quality changes quickly: the number of pollutants when you wake up in the morning can spike in mere minutes during rush hour.
Fortunately, air quality forecasting methods have become robust and reliable. Air quality monitors measure real-time pollution data and analyze historical pollution patterns to predict future air pollution, even at your neighborhood level. This technology can help you optimize your workout to limit your exposure to pollutants.
1. Monitor your local air quality
The AirVisual app by IQAir gives live air quality readings and short-term forecasts from outdoor monitoring stations operated by both government agencies and public health organizations.5
The IQAir pollution map gives readings of current and historical concentrations of five key pollutants in over 80,000 locations around the world:
- PM2.5: Particles, often from exhaust, smaller than 2.5 microns. They affect everyone and can get into your bloodstream.
- PM10: Coarse particles like dust and mold that are smaller than 10 microns. Even at low levels, they can trigger allergies and asthma.
- Sulfur dioxide (SO2): A gas that reacts easily with other chemicals and make it hard for you to breathe.
- Ozone (O3): A gas created when heat reacts with pollutants at ground level, creating a thick haze called smog.
- Carbon monoxide (CO): An odorless gas that’s toxic at high levels.
- Nitrogen dioxide (NO2): A harsh-smelling gas that can cause breathing problems.
The IQAir pollution map measures concentrations of these pollutants on a 1-500 scale. You may need to change your outdoor exercise schedule or location depending on pollutant concentrations:
- Good (0-25): Air quality is good. It’s safe to exercise outdoors.
- Moderate (26-50): Air quality is fine. Raised levels of pollutants may affect your breathing if you exercise outdoors, especially if you have asthma or allergies.
- Moderately Unhealthy (51-100): Raised levels of pollutants may affect your breathing if you exercise outdoors, even for healthy individuals. Pollutants can cause health problems if you have a lung or heart condition. Try to exercise indoors or keep your outdoor workout short.
- Unhealthy for Sensitive Groups (101-150): Pollutant concentrations affect everyone, especially those with lung or heart problems. Exercise indoors to reduce exposure to pollution.
- Very Unhealthy (151-200): Pollutant concentrations can cause health problems for everyone. DO NOT exercise outdoors.
- Hazardous (201-500): Air quality is bad enough to be declared an emergency. Stay indoors or evacuate the area until air quality improves.
For highly accurate local air quality readings, use an air quality monitor. These monitors measure key indoor and outdoor air pollutants in your immediate surroundings.
The AirVisual Pro also provides 72-hour air pollution forecasts based on trends in local pollutant concentrations. If your forecast shows that air quality will be poor for the next few days, you may want to work out indoors or somewhere else that’s not as polluted so that you don’t jeopardize your outdoor exercise benefits.
2. Know the biggest influences on air quality: Weather and human activity
Air quality can change quickly due to both weather and human activity. Air quality forecasts are often adjusted based on weather patterns. But pollution from human activity can drastically affect air quality forecasts within hours or even minutes.
Take some of the following factors into consideration before you leave your home to exercise.
The effects of weather on air pollution
The weather naturally influences pollutants that affect air quality every day.
Heat from sunlight reacts with pollutants near the ground, such as nitrogen oxide (NO), to create smog. Smog can trigger asthma symptoms and cause your breathing to become more shallow, making exercise more difficult.6In general, avoid exercising outdoors on hot, sunny days.
Cold weather often results in warm, upper-atmosphere temperature inversions. These inversions trap pollutants in cold air lower in the atmosphere.7 With no way to rise and disperse, pollutants from vehicles, industry and even fireplaces quickly create a concentrated, low-lying haze of smoke, carbon monoxide (CO) and ultrafine particles (smaller than 0.1 microns) that can get into your bloodstream. Try not to exercise outdoors on cold, hazy days.
Winds can sweep pollutants out of an area and decrease their concentrations, improving air quality quickly. But winds can also blow up dust and make air dangerous to breathe.8 Wind can also blow in pollutants far from their original source. Toxic wildfire smoke in one part of a state can be blown hundreds of miles away towards large cities, affecting millions of people. Industrial emissions can spread for thousands of miles through global wind currents.9It’s usually okay to exercise on a windy day, but keep a close watch on air quality readings.
Rain can have a cleansing effect on polluted areas. Raindrops pull pollution particles out of the air as they fall to the ground based on several factors: how high the raincloud is, how big raindrops are and how big and concentrated pollution particles are.10Exercise outdoors right after major rainfalls when particle concentrations are lower to limit your exposure to pollutants.
The effects of human activity on air pollution
The most common sources of air pollution from human activity include:
- Vehicles on streets and highways, especially during rush hour traffic. Rush hour traffic usually peaks from 6 a.m. to 10 a.m. and from 4 p.m. to 8 p.m. Pollutant concentrations rise and fall regularly due to fluctuations in vehicle traffic.
- Emissions from industrial buildings, such as factories, shipyards and power plants. Factories and power plants often run 24 hours a day. These emissions don’t change much over time.
- Emissions from agriculture, including methane from livestock.
- Smoke from using tobacco and burning fuel, especially wood used to cook or provide heat. During cold winter days, indoor and outdoor pollution can suddenly spike from the use of firewood and gas fireplaces.11
Some regional governments declare Air Quality Alerts or Action Days when pollution spikes. During these alerts, governments may limit fuel burning, factory operations and even vehicle use to reduce pollution.12,13 When certain pollution sources are banned or limited, air quality can improve within hours, making it safe to exercise outdoors again.
3. Know how pollution affects you when you’re exercising
You typically take about 15 breaths per minute during normal activities. When you exercise, you can take up to 100 breaths per minute.14 More breaths introduce more pollutants in your airways. When pollution is heavy, you can breathe in up to four times more harmful particles into your lungs. PM2.5 particles can build up in your arteries as plaque. Plaque buildup makes you more likely to develop heart disease and increases your risk of early death.15,16
Dehydration and stress from exercising can make the effects of pollutants worse.
Inhaling large amounts of dry air can make you more susceptible to the effects of airborne pollutants. Dehydration and stress from exercising can also make the effects of pollutants worse. Breathing quickly and heavily while inhaling pollutants over a long period of time can cause asthma, heart disease and lung cancer.17
4. Change your habits to protect your lungs.
- Exercise early in the morning or late in the evening. Vehicle traffic is usually lighter and pollutant levels are lower during these times.
- Exercise in open spaces away from traffic. Work out at home, in parks, or on designated paths far from busy streets or highways. If you’re exercising near vehicles producing exhaust, safely move away from or around the vehicles.
- Use a high-performance air purifier when exercising indoors. Indoor Air Quality (IAQ) is generally worse than outdoor air quality.18 Poor air quality can affect your health even if you exercise at home or at a fitness center.
- The IQAir HealthPro Plus filters up to 99.5% of harmful particulates down to 0.003 microns, keeping your indoor air safe for exercise.
- When you’re away from home, the Atem personal air purifier filters up to 99% of particulates in your personal breathing zone, letting you breathe pure air even in polluted environments like crowded gyms.
Poor air quality can keep you from getting in shape. But with air quality data and knowledge of air quality sources and patterns, you can help yourself get the best workout with the cleanest, safest air possible.
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 Pierson WE, et al. (1986). Implications of air pollution effects on athletic performance.
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 Kelly FJ, et al. (2011). Monitoring air pollution: Use of early warning systems for public health. DOI: 10.1111/j.1440-1843.2011.02065.x
 Schnell JL, et al. (2017). Co-occurrence of extremes in surface ozone, particulate matter, and temperature over eastern North America. DOI: 10.1073/pnas.1614453114
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 Nace T. (2017). China shuts down tens of thousands of factories in widespread pollution crackdown.
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 Ambient (outdoor) air quality and health (fact sheet). (2016).
 Arbex MA, et al. (2012). Air pollution and the respiratory system. DOI: 10.1590/S1806-37132012000500015
 Kippelen P, et al. (2012). Respiratory health of elite athletes – preventing airway injury: a critical review. DOI: 10.1136/bjsports-2012-091056
 The inside story: A guide to indoor air quality. (2017).