Activity 1: Smog City

Smog City is a simulation of the factors that affect the ozone. You might have noticed that ozone level really depends on the temperature, wind, cloud cover and inversions. However, there are other factors involved in the urban areas which are: emissions, industry and consumer products. There are several ways to identify ozone concentration first in measurements of nitrogen oxides plus volatile organic compounds and carbon monoxide. Measurement units are parts per million (ppm) or parts per billion (ppb). The numbers range from 0 to 0.125 ppms of O₃ which means from no ozone to extremely severe and each number is given a color to identify the intensification level ozone. Refer to the table below to identify the range in ozone levels.

Here is another interpretation of the concentration levels of ozone around the country. Analyze the map below and move your mouse around to discover the smoggiest regions in the United States.

You may remember from the map that California had the most severe levels of ozone since 1997. But, did you now that Houston surpassed Los Angeles as the smoggiest city in the United States? Yes, this is your Houston!

Ozone is measured with high tech instruments. Scientists measure the contaminants in the air in parts per million or parts per billion. What do we mean by this? To give you an idea about what parts per million (ppm) would represent just imagine the value of a penny on $10,000 or one minute in two years. Thus, a part per billion (ppb) can be imagined as one penny in $10,000,000 or one second in 32 years. Which one is a greater amount of concentration?

1 ppm = 10³ ppb

In case you haven't realized it you as a citizen have a responsibility to towards your environment. The Environmental Protection Agency has established some norms which we have to follow in order to attain clear air. The EPA has established a set of National Ambient Air Quality Standards through the Clean Air Act of 1990. The NAAQS are intended to protect all environment from O₃ in a two types of populations–the primary and secondary. The primary standards are set to protect the people who have asthma, children and the elderly. The secondary standards are limits to protect all public welfare, crops, vegetation, animals and buildings.

However in 1999, the U. S. Court of Appeals for the District of Columbia Circuit ruled that the national ozone standard to be 0.08 on an eight hour day for the safety of all environment. For more information on the National Standards go to www.epa.gov/airs/criteria.html.

Students are now ready to play with some data from your city. Your goal to reduce the level of ozone in your city by a certain percentage in order to obtain the National Air Ambient Quality Standards set by the Clean Air Act of 1999, refer to A Quick Guide to Using the Air Quality ModelA Guide to the Air Quality Model Interface and then run model EKMA/OZIP.

Use Smog City to investigate the effects of weather (temperature, wind speed, cloud cover, and temperature inversions), population (number of people), and emissions (pollution coming from motor vehicles, houses, and factories) on the air quality.

An image of the Smog City interface is shown below. On the left side of the interface, you have controls for weather-related factors, such as temperature, temperature inversions, wind speed, and cloud cover. To change a weather factor, click on the item. For temperature and wind speed, click on the indicator to increase or decrease the value.

1. Cars and trucks: cars and trucks emit a number of ozone-forming chemicals,such as nitrogen oxides (NOx), volatile organic compounds (VOCs), and carbon monoxide (CO). The more cars and trucks you have, the more emissions you have!
2. Off-road vehicles: these include airplanes and trains. These vehicles also emit a variety of ozone-forming pollutants.
3. Industry: many industries (factories) emit pollutants, especially those factories that burn coal to produce electricity
4. Consumers: the products we use in the home also produce pollution that result in bad air quality! The more we use these products, the worse our air quality becomes!

1. Green: good air quality, safe for all persons
2. Yellow: moderate air quality, people with breathing or lung problems should not spend a lot of time outside
3. Orange: unhealthy for sensitive groups, such as people with lung diseases, young children, and elderly persons
4. Red: unhealthy for all persons. Time outside should be limited!
5. Purple: very unhealthy! A good day to stay indoors!

You are now ready to run Smog City!. Once you click on the "run Smog City" link, it will take a few minutes for the simulator to load. Have fun!