Exposure and Risk
A person can get asthma at any age. Asthma affects all races, ages, and genders. Although asthma affects people of all ages, it often starts in childhood and is more common in children than in adults. The most common outdoor triggers for asthma attacks are pollen, exercise, pollution such as particulate matter and diesel fuel, and pesticides. Indoor triggers for asthma include mold, dust, secondhand smoke, and pet dander.
Air pollution, such as ozone and particle pollution, can make asthma symptoms worse and trigger attacks. Adults and children with asthma are more likely to have symptoms when ozone and particle pollution are in the air. Ozone is often found in smog and particle pollution is often found in haze, smoke, and dust.
Ozone is often worst on hot summer days, especially in the afternoons and early evenings. Particle pollution can be bad any time of year, even in winter. It can be especially bad:
- when the weather is calm, and air pollution can build up,
- near busy roads, during rush hour, and around factories that produce air pollution and,
- when smoke is in the air from wood stoves, fireplaces, or burning vegetation.
Important asthma triggers are:
- environmental tobacco smoke, also known as secondhand smoke;
- dust mites;
- outdoor air pollution;
- cockroach allergen;
- strenuous physical exercise;
- some medicines;
- bad weather, such as thunderstorms, high humidity, or freezing temperatures;
- some foods and food additives; and
- strong emotional states that can lead to hyperventilation and an asthma attack.