On a bad day, that distance can be reduced to 40 miles. Several expensive and complex devices are used to monitor visibility, but so far no standards have been set at any government level for acceptable visible pollution. Low visibility is created through the combination of fine particulates, gases and moisture in the air. Visible air pollution poses an aesthetic and economic problem, and may have some health implications. More study is needed on this topic.
Carbon monoxide reduces the blood's ability to transport oxygen.
The body must work harder to perform the same exercise. This problems is compounded at high altitudes. Extremely large amounts prove fatal. National Standards Conditions that Promote High Levels of Pollutants Little or no air movement to disperse pollutants. Lack of precipitation to cleanse air.