Asthma and allergy

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During the last two decades, many scientific studies have documented the link between air pollution and human health. Pollutants such as pm 10 and (particles less than 10 and 2.5 microns in size), nitrogen oxides ( no x ), sulphates, ozone, and acid aerosols have been found to be associated with death, asthma, cardiovascular and respiratory diseases, says Susannah Foster in a study prepared for the Boston Public Health Commission and Harvard Medical School.

Additionally, ultrafine particles (less than 2.5 microns in size), which are found in diesel exhaust, have been directly associated with an increased risk of premature death. These particles have hundreds of chemicals adsorbed onto their surfaces, including many known or suspected mutagens and carcinogens, and because the are so small, they can be inhaled deep into lung tissue.

Quantitative knowledge of the health effects of particulate air pollution dates back to 1952 when London was covered in a thick smog from coal emissions. Forty-one years later, in December 1991, another high-pressure system set in over London. This time, it was not coal emissions, but automobile emissions that were trapped into the atmosphere. During this unusual week, there was a 10 per cent increase in mortality, and a 14 per cent increase in cardiovascular disease. For the elderly, hospital admissions for respiratory disease increased by 19 per cent and 43 per cent for obstructive lung disease.

The landmark study of six us cities in 1993 found that, after taking into account other risk factors, mortality was 26 per cent higher in the most polluted city versus the least polluted one.

Diesel engines are one of the biggest polluters in us cities. They account for 44 per cent of no x emissions and 69 per cent of particulate emissions from transportation. Emissions from diesel engines contain 40 times the amount of no x as compared to petrol engines.

Diesel exhaust as compared to other sources of pollution is emitted in close proximity to where people live and work. Many studies have demonstrated a correlation between how close one lives to a major road or highly-trafficked area and increased symptoms of asthma and respiratory disease. Researchers estimate that nationwide, tens of thousands of people die prematurely each year as a result of particulate pollution. Diesel engines are a major contributor to the problem, releasing particulates directly into the air and emitting no x and sulphur oxides and transform into particulates in the atmosphere. Overwhelmingly, the results indicate a connection between air pollutants and decreased human health:

diesel and asthma: