Let's start with asthma. A recent study says that traffic pollution may boost the risk of children getting asthma, especially if their genes predispose them for that vulnerability. The University of Southern California team studied the health records and genetic profiles of 3,000 children. Those children who had a gene variation were slightly more at risk if they lived near a main road.



The researchers found that children who had high levels of EPHX1 were 1.5 times more likely to have been diagnosed with asthma, while children who also had variations in GSTP1 were four times as likely to have asthma. Living close to a main thoroughfare appeared to increase this effect.

This study is one of the first to look specifically at how genetic vulnerability to respiratory disease and environmental traffic fumes can cause childhood asthma in children with active EPHX1 variations in the gene and a home near a road a risk nine times greater than average.

The study's conclusion stated that, while children with the identified genes and enzyme activity were more prone to having asthma, living near a road seemed to compound that risk.

A more recent US study suggests that diesel exhaust particles in air pollution, combined with artery clogging "bad" cholesterol, can increase an individual's risk of cardiovascular disease. Together, these two substances switch on genes causing inflammation of artery walls that eventually harden. All this makes it more likely that an individual will suffer a heart attack or stroke. The study is published in the journal Genome Biology and is the work of scientists at the University of California in Los Angeles (UCLA).

Dr. Andre Nel, chief of nanomedicine at the David Geffen School of Medicine at UCLA and researcher at UCLA's California NanoSystems Institute said that when the diesel particles combined with blood fats, their impact was stronger than their individual effect. "When you add one plus one, it normally totals two," he said.

"But we found that adding diesel particles to cholesterol fats equals three. Their combination creates a dangerous synergy that wreaks cardiovascular havoc far beyond what's caused by the diesel or cholesterol alone."

Researchers reported that the studys findings could explain why hospitals admit more heart disease cases, and why more people die from it, when air pollution in an area increases.

There have been previous studies that suggested links between an increase in airborne particles and increased deaths from heart disease. The American Cancer Society estimates that, for every 10 micrograms per cubic meter rise in air particulates, heart and lung related deaths go up by six percent.

Researchers report that they don't know exactly how air pollutants damage the arteries. "We do know that these particles are coated with chemicals that damage tissue and cause inflammation of the nose and lungs," Nel explains. "Vascular inflammation in turn leads to cholesterol deposits and clogged arteries, which can give rise to blood clots that trigger heart attack or stroke."

Researchers also say that these findings emphasized controlling air pollution is another way to combat the increase in cardiovascular disease.