The Automobile and Air Pollution* by Herbert D. Peckham, Gavilan College The most logical place to begin our study of air pollution is with the automobile. Table 1 presents some very interesting statistics concerning the relationship between cars and air pollution. First, the overall quantity of pollutants (141 million tons per year) is absolutely depressing! Second, the automobile plays a discouragingly large part in the overall pollution. Certainly in the production of carbon monoxide (93% of the total) and organics (66% of the total), the automobile is the villain! Last, it is clear that the automobile has little to do with pollution from sulfur oxides and particulates. Table 1 ~ Total US Air Pollution (1970) Millions of Tons Per Year % Caused Pollutant Auto Other Total by Auto Carbon Monoxide 66 5 71 93 Organics 12 7 19 63 Oxides of Nitrogen 6 7 13 46 Sulfur Oxides 1 25 26 4 Particulates 1 11 12 8 Total Pollutants 86 55 141 61 Before we can start building our automobile air pollution models, we need to know the rates at which automobiles produce the various pollutants. Of course, this is continually changing as automobile pollution controls become more severe. We will use 1970 estimates (hopefully, by 1980 or 1990 the values will be much lower). Also, we will assume a standard velocity of 40 miles per hour. Do you feel this is a reasonable choice? The rates of pollutant production are given in Table 2. Table 2 - Average 1970 Pollutant Production Rates per Automobile Traveling at 40 MPH Pollutants Rate of Production Gases liters/mile cubic feet/mile grams/hour Org. 4.5* 6.4 483 NOX 3.4** 4.8 231 SOX 0.1*** 0.14 11.4 CO 54.1 76.6 2710 (grams/mile) (grams/hour) Particulates 0.5 20 *Assumes an average molecular weight of 60. Gas volumes computed at standard temperature and pressure. **Assumes equal parts nitric oxide and nitrogen dioxide are formed. Average molecular weight of oxides of nitrogen assumed to be 38. ***Assumes 4 parts sulfur dioxide to I part sulfur rrioxide are farmed. Average molecular weight of sulfur oxides assumed to be 67. *This activity is reproduced from the Student Lab booklet Air Pollution from the Hewlett-Packard Computer Curriculum Series. Additional Background material and exercises are in the booklet. The Student Lab book and companion Teachers Advisor book are available for $1.00 each from Hewlwtt-Packard Computer Curriculum Project, 333 Logue Avenue., Mountain View, California 94043.