Nearly 25 million people of all ages in the United States are living with asthma, a lifelong chronic disease that makes it harder to move air in and out of the lungs.

Here’s what the American Lung Association wants everyone to know during summer, when extreme heat can make asthma harder to manage.

1. New challenges are emerging.

Beyond traditional asthma triggers like respiratory infections, secondhand smoke and pets, new challenges are emerging. The effects of climate change include extreme heat, poor air quality, increased allergens, extreme weather events, and more frequent and intense wildfires, all of which are making asthma more difficult to manage.

Excessive heat and humidity increase the risk of asthma exacerbations, asthma-related hospitalization and asthma-related death, especially for children and women. Patients should limit time outdoors during heat waves, seek access to air conditioning and take steps to improve indoor air quality, as humidity allows dust mites and mold to thrive.

2. City dwellers are particularly vulnerable.

Two-thirds of the average U.S. city is made up of roads, parking spaces, sidewalks and roofs. Since these surfaces are typically dark and non-porous, they contribute to flooding, increased air pollution, poor health and what is known as “urban heat,” a phenomenon in which cities experience warmer temperatures than surrounding areas. Urban heat, combined with pollutants from power plants, motor vehicles and other pollution sources, creates ozone pollution, also known as smog. Those with asthma can experience symptoms like shortness of breath, wheezing and coughing from both ground-level ozone and particle pollution, as well as from the impacts of extreme weather and airborne allergens.

Sadly, these issues disproportionally impact certain communities. Due to a history of discriminatory practices like systematic denial of mortgages, insurance loans, and other financial services on the basis of race and ethnicity, Black and Indigenous people, and other people of color, are more likely to be living in areas impacted by urban heat and poor air quality.

3. Flooding can harm lung health.

Increased severe storms due to climate change results in more flooding, which can harm lung health. Chemicals, sewage, oil, gas and other dangerous substances found in floodwaters can pose health risks, and mold, associated with asthma attacks, can grow anywhere there is water or dampness.

4. Advocacy efforts are underway.

The Smart Surfaces Coalition is made up of 40 national and international organizations committed to making Smart Surfaces the global urban design standard. Smart Surfaces encompass a suite of cutting-edge technologies, including reflective (cool) roofs and pavements, green roofs, trees, solar panels and rain gardens. Designed to mitigate urban heat, enhance air quality and improve health, these transformative urban features can cool cities by 5 degrees F, reduce flooding, provide economic benefits and potentially advance environmental justice.

The American Lung Association, an active member of the Smart Surfaces Coalition, encourages cities to take these actions:

• Install light-colored roads, parking lots and driveways to reflect sunlight and reduce heat.

• Install solar panels to convert sunlight into electricity and provide shade for roofs.

• Plant trees to increase shade.

• Select porous surfaces to collect polluted stormwater, soak it into the ground, and filter out pollution.

Other strategies to reduce urban heat, air pollution and ozone levels include using public transportation carpooling, increasing green spaces and installing cooling centers in extreme conditions.

5. Resources are available.

Educational programming can help people better manage the disease in summer and year-round. Patients can check out the self-management education programs, information and tools available at Lung.org/asthma or call the American Lung Association’s Lung Helpline at 1-800-LUNGUSA. Living with an illness, or being the caretaker to someone who is, can take a physical and emotional toll. Patients can get support and knowledge, and connect with others by joining the Lung Association’s Patient & Caregiver Network.

For the 24.8 million Americans living with asthma, extreme summer temperatures and emerging environmental threats can make life more difficult. Fortunately, new educational resources and expanded programming can help patients navigate new and old challenges alike.