The World Health Organization has stated that air pollution accounts for 1.3 million deaths worldwide every year. This article reviews the association of air pollutants with all major causes of death. Those associations understood, it becomes clear that outdoor air pollution is likely to be an even greater cause of mortality across the globe than is currently recognized.
This paper is part of our Environmental Medicine Special Issue. Read the entire issue below.
|Deaths in Millions||% of Deaths|
|Ischemic heart disease||7.25||12.8|
|Lower respiratory infection||3.46||6.1|
|Chronic obstructive pulmonary disease||3.28||5.8|
Table 1. Major Causes of Death Compiled From World Health Organization Statistics1
Urban Air Pollution Levels
Polycyclic Aromatic Hydrocarbons
|Polycyclic Aromatic Hydrocarbons||Probable Carcinogens per US Environmental Protection Agency||Present in Diesel Exhaust|
Table 2. The 17 Most Common Polycyclic Aromatic Hydrocarbons in Outdoor Air
Industrial- and Vehicle-generated Volatile Organic Compounds
VOCs, also referred to as solvents, are typically short-chain hydrocarbons that evaporate rapidly at ambient temperatures and have a variety of industrial uses.27 VOCs are used in paints, glues, inks, fragrances, and building materials and are found in cigarette smoke, gasoline, and vehicular exhaust. The 4 most common VOCs are benzene, toluene, ethylbenzene, and xylene; they are often referred to simply as BTEX and can account for up to 27% of each gallon of gas dispensed at the pump for every vehicle.28 For the United States as a whole, vehicular emissions are the greatest source of these compounds found in urban and rural air, but in areas of the country where refineries and chemical plants are located, these nonmobile sources far surpass emissions put out by transport vehicles. The EPA website provides information on the total VOC emissions for the entire United States or by state or county.
Data from the 1990 US EPA Cumulative Exposure Project looked at 148 toxic air contaminants for each of the 30,803 census tracts in the contiguous United States.29 Concentrations of benzene, formaldehyde, and 1,3-butadiene were greater than levels known to cause cancer (cancer benchmark levels) in over 90% of the census tracts. Approximately 10% of the census tracts had 1 or more carcinogenic hazardous air pollutant in concentrations above 1-in-10,000 risk levels. As an example, these data revealed that of 25 sites in Minnesota, 10 pollutants were found that exceeded the benchmarks in 1 or more sites (acrolein; arsenic; benzene; 1,3-butadiene; carbon tetrachloride; chromium; chloroform; ethylene dibromide; formaldehyde; and nickel).30
|Rural Rides (blood ng/L)||Urban Rides (blood ng/L)|
|Rural Rides (urine ng/L)||Urban rides (urine ng/L)|
Table 3. Data From Bergamaschi et al: Bicyclist Biomarkers of Internal Dose in Pre-ride and Post-ride Blood and Urine Samples32
Air is vital for human life, with the average adult breathing in over 17,000 times every day. Unfortunately, with very few exceptions, each of those daily breaths may come with a substantial number of toxicants with severe health consequences.
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