It appears that living in major urban areas such as New York or Los Angeles increases the risk of developing cancer. New Yorkers' risk of developing cancer from air toxins is estimated to be 68 residents per million. In California, the risk is 66 residents per million. The national average is 41 per million, according to the report based on emissions of 177 chemicals in 1999, the most recent data available. Oregon, Washington, D.C., and New Jersey had the third, fourth and fifth worst air in the nation, respectively, the EPA has said. Rural residents of Wyoming, South Dakota and Montana breathed the cleanest air. The EPA assessment evaluated toxins including heavy metals, such as lead; volatile chemicals, such as benzene; combustion byproducts, such as acrolein; and solvents, including perchloroethylene and methylene chloride. Benezene alone contributed a quarter of the individual cancer risk identified in this assessment, the primary source of it being vehicles. The National-Scale Air Toxics Assessment (NATA) is a screening tool that estimates cancer and other health risks from exposure to air toxins. It provides a snapshot of air quality and the risks if 1999 emissions levels remained unchanged. It does not reflect reductions in air toxins that may have occurred since 1999.

Air pollution and atherosclerosis
The closer a person lives to heavy traffic and resultant air pollution, the more likely he or she is to have atherosclerosis. Large population studies have shown pollution from the exhaust of trucks, buses and coal-burning factories increases the risk of fatal heart attacks and strokes. The atherosclerosis risk associated with living near a busy street is may be greater than the risk associated with second-hand smoke exposure.Tiny particles of air pollution -- less than one tenth the width of a human hair -- can trigger clotting in the blood. This may explain how air pollution increases the risk for heart attacks and strokes.

According to a report in the Sept 13, 2007 issue of The New England Journal of Medicine, in men with a history of coronary heart disease, inhalation of pollution in the form of dilute diesel exhaust increases myocardial ischemia and inhibits fibrinolysis, Lead researcher Dr. Nicholas L. Mills, from the University of Edinburgh in the UK, and colleagues conclude, "In light of these findings, environmental health policy interventions targeting reductions in urban pollution should be considered in order to decrease the risk of adverse cardiovascular events,"

Air pollution and brain function
Inhaling diesel exhaust may damage brain function. Small particles of soot, or nanoparticles, are able to travel from the nose and lodge in the brain. The long-term effects of exposure to traffic nanoparticles interferes with normal brain function and information processing. Air pollution and inhaling of car exhaust may be another cause of cognitive decline.

Air Pollution and Lung Cancer
Tiny metallic bits of air pollution could account for some cases of lung cancer. Texas researchers at the University of Texas Southwestern Medical Center at Dallas aren't sure exactly how dangerous the particles are, nor do they fully understand their potential relationship to tobacco smoke. About 10 percent to 15 percent of lung cancer cases occur among nonsmokers. One possible explanation: Inhalation of air pollution, especially fine particulate matter -- bits of metal that are too small to be seen with the naked eye but can still enter the lungs. Mining, smelting and petroleum production all produce this type of pollution.
   Radon is a radioactive gas that can cause bodily harm.

Air Pollution and Stroke
The risk of death due to hemorrhagic stroke is associated with exposure to high concentrations of particulate matter about 2 hours before death. Dr. Shin Yamazaki, an epidemiologist at Kyoto University, and associates collected data from the 13 largest cities in Japan regarding concentrations of suspended particulate matter 7 µm diameters or higher (PM7), ambient temperature, plus other components of air pollution, from January 1990 to December 1994. According to their analyses, the odds ratio (OR) of death from ischemic stroke was associated with temperatures above 30 degrees centigrade in the warmer months compared with moderate temperatures of 15 to 22 degrees (OR 1.333). In contrast, the risk of death due to intracerebral hemorrhage was increased in cold weather (0 to 8 degrees, OR 1.225). However, during warmer months, a 1-hour mean concentration of PM7 > 200 µg/m³ increased the risk of death from intracerebral hemorrhage (OR = 2.397), an association independent of 24-hour mean PM7 concentrations. In contrast, death due to ischemic stroke was not associated with 1-hour PM7 levels. Dr. Yamazaki's team suggests this discrepancy may be due to the longer interval from ischemic stroke onset to death, or to the fact that inhaled particles raise blood pressure, a risk factor for intracerebral bleeding. Moreover, they write, "during the 4 years covered by this study, there were 443 hours in which the concentration of PM7 was over the 1-hour air quality standard (in Tokyo), and that 49 of those hours (11%) occurred on days when the 24-hour mean concentration of PM7 was within the air quality standard for 24-hour periods." Occupational and Environmental Medicine, 2006.

Air Pollution and Pregnancy, and premature delivery
Pregnant women who are exposed to low levels of air pollution seem to have an increased risk of giving birth before term. Women who live in areas with high carbon monoxide or fine particle levels - pollution caused mainly by motor vehicle traffic -- are more likely to have preterm birth (delivery before 37 weeks of pregnancy), compared with women who live in less polluted areas. This is especially true for women who breathe polluted air during the first 2 or 3 months of pregnancy or during the last weeks before delivery.

Air pollution in children
Traffic pollution can prevent the lungs of children who live near busy roads from developing properly, making them more likely to suffer respiratory and heart problems later in life. Children who live within a few hundred yards of a highway have less lung function when they reach adulthood than children exposed to much less traffic pollution.
   Toddlers who breathe polluted air are more likely to be diagnosed with bronchitis than children living in cleaner environments. Polycyclic aromatic hydrocarbons, or PAHs, are strongly linked with cases of bronchitis among children aged 2 to 5. PAHs are produced when fuels that contain carbon such as wood, coal, diesel or tobacco are burned.

Air pollution from driving on freeway
A driver on a busy morning freeway inhales more pollution than in the entire rest of the day. Drivers in heavy traffic are  exposed to diesel and ultrafine particles. On freeways, diesel-fueled trucks are the source of the highest concentrations of harmful pollutants. Ultrafine particles are of particular concern because, unlike larger particles, they can penetrate cell walls and disperse throughout the body. Particulate matter has been linked to cardiovascular disease, but the ultrafine fraction on roadways appears to be more toxic than larger sizes. Driving with the windows closed and using recirculating air settings can modestly reduce the particle pollution exposures but does not reduce most gaseous pollutants.

Pollution from school buses
School buses can be a major source of pollution exposure for children. Ninety-five percent of the nation's school buses are diesel-powered, and some are recommending that they be refitted with fuel oxygenators or other anti-pollution equipment. The oldest buses seem to pump out soot every time they climb a hill or accelerate. Those buses produce as much as 20 times the pollution of newer models. Several states are using alternative-fuel buses, replacing older buses with cleaner-burning models or retrofitting buses with devices that trap emissions. A considerably more low-tech method also can reduce children's exposure to bus pollution, especially as they wait in the parking lot for a ride home.

Pollution in California
Air pollution in California's San Joaquin Valley imposes $3 billion annually in health-care, lost productivity and other costs on the farm-rich region. University researchers used measures such as premature deaths, asthma attacks, cases of acute bronchitis, hospital admissions, school absences and lost work days for their estimates on the effect of air pollution in the valley.

Pollution in China
China's longest river is full of pollution and rapidly dying, threatening drinking water supplies in many cities along its banks. Chinese environmental experts fear worsening pollution could kill the Yangtze river within five years. Industrial waste and sewage, agricultural pollution and shipping discharges were to blame for the river's declining health.
   Worsening air and water pollution and frequent use of food additives and pesticides made cancer the top killer in China in 2006. About 460,000 Chinese die prematurely each year from breathing polluted air and drinking dirty water.

Air Pollution in Hong Kong
Hong Kong's air pollution may be responsible for a jump in children being admitted to hospital for asthma, a six-year study has found. The study, published in the June, 2006 issue of the medical journal Clinical and Experimental Allergy that is soon to be distributed, is certain to heighten concerns over the city's worsening air pollution. Companies in Hong Kong have blamed the territory's air pollution for driving away some expatriates and making it more difficult to recruit foreign workers in recent years. Using hospital admission records in the years 1997 through 2002, researchers at the University of Hong Kong found that a total of 26,663 children were admitted into hospital for asthma during the six-year period. After days when pollutants such as nitrogen dioxide, ozone and respirable suspended particulates were especially high, the numbers of children admitted for asthma would rise by 13 percent on average, according to the study. "Air pollution is triggering such bad asthma that they need to be admitted into hospital. (And these cases) are just a tip of the iceberg," says Lee So-lun, honorary clinical assistant professor of pediatrics and adolescent medicine at the University of Hong Kong.

Air pollution from fire
When a fire burns it generates carbon dioxide, water vapor, carbon monoxide, particulate matter and other chemicals.
And the wind can carry those particles to areas far from the fires. People with asthma or other lung conditions can see their condition getting worse by inhaling the pollution from the fire.

Dioxin pollution
More girls than boys are born in some Canadian communities because airborne pollutants called dioxins can alter normal sex ratios, even if the source of the pollution is many miles away.

Pollution Questions
Q. Could alpha lipoic acid be helpful in reducing toxin damage from air pollution?
   A. It's difficult to say, I am not sure.

Q. I heard about a chemical called bisphonal, is it safe?
   A. See bisphenal a for a discussion on this topic.