Frequently Asked Questions

Why is the map shaded green?

The green area represents the area for which the map calculates ozone concentrations. The map uses data from forty-five monitors in the Houston area to calculate the amount of ozone in the air at all points in the shaded area.

Why don’t I see anything on the map?

Thankfully, there’s often no elevated ozone levels in Houston. Ozone is worst when conditions are hot and still. If the entire map is the same color green, that means there’s no ozone in Houston. Go outside and enjoy your day!

How can I see what the map looks like when there IS ozone?

You can use the map to view historical ozone days. From the home page, click on “Set Time/Place.” Set the time for June 26, 2012 from 1:00-5:00 pm, and click “Refresh Map.” You’ll see what the map looks like on a high ozone day.

Is this a satellite image?

No. While it’s useful to think of the ozone map like a weather map, this isn’t a satellite image like you might see for cloud cover. It is a tool to help you visualize how ozone pollution forms and moves. It uses data from ozone monitors to project ozone levels and movement throughout the Houston area. The actual ozone concentration at a particular spot may not match the projection exactly.

What is the color bar on the right? What do the numbers on the bar mean?

The color bar represents the Air Quality Index (AQI). The numbers on the bar represent the concentration of ozone in the air in parts per billion. The AQI assigns a color and level of concern to ranges of ozone concentrations. The Environmental Protection Agency (EPA) developed the AQI to aid public awareness and to enable individuals to understand the daily local air quality.

How worried should I be if the map shows yellow?

For any color, you should refer to the Air Quality Index. Yellow represents a moderate amount of ozone. Only people who are unusually sensitive to ozone should consider limiting their exposure. This includes people with lung diseases such as asthma, chronic bronchitis, and emphysema; children; and the elderly.

Are there physical signs of ozone exposure?

There are many symptoms of ozone exposure, including headache, itchy or burning eyes and throat, shortness of breath, wheezing, coughing and chest pains. Ozone is also linked to more serious health effects, such as asthma attacks in those suffering from asthma, pulmonary infections, and increased risk of heart attack.

How can I tell if ozone is a trigger for me?

If you experience any of the symptoms listed above, you may be sensitive to ozone. You should also be aware if you are a member of a group that is particularly sensitive to ozone such as children, the elderly, and people with respiratory diseases such as asthma, emphysema, and chronic obstructive pulmonary disease (COPD).

Why is exercising a particular problem on high ozone days?

When we exercise, we breath faster and deeper, which draws more ozone into our lungs. Also, many people exercise outdoors, where ozone levels are higher. If you often exercise outdoors, you should take steps to limit your exposure to ozone pollution.

How else can I get this information?

There’s a free ozone app for mobile phones! Seach "OzoneMap" on your phone or visit the iTunes Store for iPhones or Google Play for Android.