Asthma is a chronic disease that affects the airways that carry oxygen in and out of the lungs. Asthma can cause

• shortness of breath,
• wheezing,
• coughing, and
• tightness in the chest.

Asthma attacks have been linked to many factors, including exposure to environmental hazards like

• allergens,
• tobacco smoke, and
• indoor and outdoor air pollution.

Asthma can be controlled by taking medication and avoiding triggers that can cause an attack.

Ozone occurs naturally in the sky and helps protect us from the sun's harmful rays. But ground-level ozone can be bad for your health and the environment. Ground-level ozone is one of the biggest parts of smog.

When ozone levels are above the national standard, everyone should try to limit their contact with it by reducing the amount of time spent outside.

residents were exposed to unhealthy levels of ozone for in .

Check the EPA's Air Quality Index (AQI) at AirNow.gov to see the current air quality conditions for your location. You can use the AQI to plan your daily activities to reduce exposure to ozone.

Air pollution is a leading environmental threat to human health. Particles in the air like dust, dirt, soot, and smoke are one kind of air pollution called particulate matter. Fine particulate matter, or PM_2.5, is so small that it cannot be seen in the air. Breathing in PM_2.5 may

• lead to breathing problems,
• make asthma symptoms or some heart conditions worse, and
• lead to low birth weight.

The national standard for annual PM_2.5 levels is 12.0µg/m³. When PM_2.5 levels are above 12, this means that air quality is more likely to affect your health.

In , the annual level of PM_2.5 in was µg/m³. *

* Micrograms per cubic meter (µg/m³)

Extreme summer heat is increasing in the United States, and climate projections indicate that extreme heat events will be more frequent and intense in coming decades. Extremely hot weather can cause illness or even death. Knowing how hot it gets in your area can help you prepare for extremely hot temperatures and prevent heat related illness.

had with maximum temperatures above 90°F during May-September .

Heat-related death or illnesses are preventable if you follow a few simple steps.

• Stay cool.
• Stay hydrated.
• Stay informed.

The environment is one of several factors that can lead to an increased risk for heart disease. High levels of air pollution and extreme hot and cold temperatures have been linked to increases in heart disease and deaths from heart attacks. A heart attack happens when a part of the heart muscle dies or gets damaged because of reduced blood supply.

In , there were

• deaths from heart attacks in .
• deaths from heart attacks in .

Having access to places for physical activity, like parks, encourages people to get active and do so more often. The closer you live to a park, the more likely you are to walk or bike there. Walking and biking to parks can decrease air pollution and car crashes, which in turn, can reduce chronic disease rates and traffic-related injuries.

In ,

of people living in lived within half a mile of a park.

of people living in lived within half a mile of a park.

Traffic-related air pollution is a major cause of unhealthy air quality, especially in urban areas. Many health problems have been linked to exposure to traffic-related air pollution. The closer your home or school is to a major highway, the more likely you and your family are to be exposed to traffic-related air pollution.

In , of the population of lived within 150 meters* of a major highway.

In , of public schools were sited within 150 meters* of a major highway.

* 150 meters is about 2 blocks.