I always marvel when we all begin our Saturday runs, taking over the streets of Salem. Even better are the beginnings of large running races where the pervasive automobile is useless and has no place. In a World Watch magazine of many years ago, it was pointed out that 3,600 pedestrians could occupy a one meter width of lane per hour as opposed to only 150 to 200 motor vehicles. This number is especially significant in a country like ours where there is roughly one automobile per 1.5 people compared to China where there are over 1,100 people per auto. The article's point of view was efficiency of moving people from a transportation aspect; however, to runners, it has significance. Our pedestrian efficiency is even more notable when you consider that it takes around 100 calories to move each of us one mile compared to an automobile that uses 1800 to 1900 calories per mile. You can see we are pretty efficient.

     The great concern, however, is that even though a byproduct of our efforts is carbon dioxide, motor vehicles emit a variety of undesirable items which all go into our shared atmosphere. Since our geographic area is undergoing a sizable increase in population and the quantity of vehicles is increasing rather substantially, the quality of the air we breathe as we run is declining. The real impetus for writing this, however, was the single comment that a long run in a polluted area is comparable to smoking a pack of cigarettes.

     You can find an inventory of exhaust byproducts by consulting the Federal Government's Department of Transportation's web site. Their list includes brief descriptions of pollutants and what each does to your respiratory system when you breathe air with higher levels of these pollutants. The text also gives recommendations for ways to avoid these peak levels.

     The most significant pollutant is ozone. Breathing large amounts of ozone can make a person cough, become short of breath, and have feelings of tightness in the chest. It can also irritate the nose, throat and eyes and limits the lung's ability to function properly. Emphysema, asthma, allergies and respiratory infections can all be caused by prolonged (years) contact with large quantities of ozone. If you exercise early in the day or after sunset, the quantities are significantly lower. Responsible weather reporters will tell you when an area is having a high pollution/ozone index, and on those days you should exercise inside or at least well away from roadways.

     Sulfur dioxide and nitrogen dioxide are pollutants that have very similar health effects to ozone. Given high enough concentrations of these pollutants, a person can suffer severe respiratory conditions. The recommendations for dealing with these is the same as for ozone.

     A somewhat more common pollutant is carbon monoxide which when inhaled limits the amount of oxygen in the blood. This condition, of course, affects your performance. If there is heavy traffic nearby, then you will be exposed to high levels of carbon monoxide and you'll find yourself running slower and with more effort than usual. The effects of exposure to carbon monoxide are greater during the winter.

     The most vague, but most harmful pollutant is simply particulate matter, which is the visible component of fog. The particles are tiny and stick to particles of dust. As we exercise we breathe them into the deepest parts of our lungs and because we breathe through our mouths rather than our noses, the primary filtration for particulate is bypassed. The results of prolonged breathing of particulate can cause severe respiratory illnesses.

     Now, not to sound like a harbinger, this information is being given to you more as data for you to use in deciding where and when to run when pollution levels become high. Salem and surrounding areas have, at times, come close to exceeding Federal standards for pollution, and if you exercise near heavy traffic, like the freeway or Highway 22, then you should be aware of what you're breathing.

     Most of the models of pollution show a gradual buildup of pollutants during a typical day and indicate that the highest levels occur late in the afternoon. The lowest pollution levels occur early in the mornings and late in the evenings, especially if a breeze occurs. During late afternoons and on high pollution days, you should be fine if you stay inside or exercise in some of the larger parks.

     Allowing yourself to be aware of the quality of air you breathe can help your performance and reduce some of those times when your breathing is somewhat impaired. May through September is typically considered smog season in many areas, and looking out over the city of Salem during the hot days of summer, it is apparent that out air is quite fouled. So, use this information to temper your decision of when to run; run early, run near rivers, run among the trees of our parks, or limit your exercise to indoors, then you should find little distress.