When you’re outdoors, you have less control over the triggers you encounter. You can’t, for example, vacuum the lawn if pollen is bothering you, and there’s no air cleaner large enough to clean a city’s air pollution.

Still, there are things you can do to help reduce you exposure to outdoor triggers. By making a few adjustments, and by taking your medication as directed, you can breathe easier when you’re outside.

Moulds are asthma triggers for many people. A type of fungus, their spores float in the air where they’re easily inhaled and can lead to coughing, sneezing, wheezing and chest tightness.

You’ll find moulds wherever it’s damp. This includes piles of vegetation, stagnant water, and garbage containers.

If you’re sensitive to mould spores, try the following:

  • Have piles of grass removed from your lawn immediately after it’s mowed.
  • When leaves accumulate on your lawn, have them raked and removed.
  • Keep garbage cans clean.
  • Have outdoor containers that hold stagnant water removed.
  • Ensure that eaves-troughs on your house face away from the house.


Pollens are a very common trigger for asthma symptoms. Generated by trees, grasses and weeds, airborne pollens are easily inhaled, especially during warm-weather months.

If you’re allergic to pollen, there are a number of things you can do to stay healthy:

  • Use a HEPA-filtered air cleaner.
  • Plant low-allergen gardens.
  • On days when the pollen count is high, use an air conditioner in your home and car, and also try to keep your windows closed as much as possible.
  • If you usually exercise outdoors, consider exercising inside on days when the pollen count is high.
  • Avoid going outside between 5 and 10 am on hot and windy days.
  • Check the pollen count to see whether you should reduce the amount of time you spend outdoors.
  • Shower and change your clothing if you’ve been outdoors on a high-pollen-count day.
  • If there are plants in your yard that trigger symptoms, have someone remove them.
  • Use a good furnace filter and change it regularly.
  • Do not place trees or plants near windows, or near the air-intake of your furnace or air conditioner.
  • Do not hang your laundry out to dry – use a clothes dryer instead.
  • Do not touch plants that you think might be triggers – and if you do, wash your hands immediately afterwards.

Cold Air

Cold air, or sudden changes in the weather, can also trigger asthma symptoms. If you’re affected by the cold, the following tips can help:

  • Try breathing through your nose. This helps warm the air before it reaches your lungs.
  • If you have to breathe through your mouth, wear a scarf or a special cold-weather mask to help humidify and warm the air you breathe, making it easier on your lungs.
  • Exercise indoors on cold days.

Air Pollutants

While air pollution as a cause of asthma has not been verified, there is good evidence that pollution causes the symptoms of many people with asthma to get worse on days when the Air Quality Health Index is high.

If you find your symptoms become worse on these days, try to:

  • Reduce the amount of time you spend outside when air-pollution is high.
  • Exercise indoors if you usually exercise outdoors.
  • Turn on the air conditioner in your home and car and keep your windows closed.