Particulate Matter (PM)--Current EPA acceptable level is 12mcg/m3 (micrograms per meter cubed) Some particles lodge in the upper airway causing asthma attacks, sore throats. Others go deep into lungs and cause both long term and short term effects leading to strokes, heart attacks, lung cancer and associated with early mortality in hundreds of studies.
Sulfur Compounds (SOx)--Current EPA acceptable level is 75 ppb (parts per billion) Directly cause airway inflammation, and compounds with ozone to increase heart attacks, lung cancer and early mortality.
Nitrate Compounds (NOx)--Current EPA acceptable is 10 ppb (parts per billion). This directly causes airway inflammation. Compounds with ozone to increase strokes, heart attacks, lung cancer and early mortality.
Ozone (O3)--Current EPA acceptable level is 70 ppl (parts per billion). Causes increased mortality from all causes, leads to heart attacks, strokes, cancers. Combines with SOx and NOx in the air often.
Carbon Monoxide (CO)--Current EPA acceptable level is directly is 9 ppm (parts per million). Is toxic to red blood cells. Impairs oxygen uptake in the blood. Typically most dangerous in a confined area so not as important in air pollution.
Lead--Lead is very dangerous at any level in the human body. Causes irreversible brain damage. More common in water, paint today. Was a major air pollutant until it was removed from gas in 1970 due to the Clean Air Act. Recent issues with Flint, Michigan water source underline how old lead pipes when not replaced can still harm citizens.
The Clean Air Act of 1963 was the start of air pollution awareness in the US. President Nixon then created the Environmental Protection Agency (EPA) in 1970. These have greatly improved our air quality over the decades. The EPA now regulates the 6 toxins noted to the left. For more information, visit the EPA website below.