Bad air can trigger in young, healthy adults a string of adverse biological changes that are linked to cardiovascular disease, a Taiwan study has shown. Writing in the second August issue of the American Journal of Respiratory and Critical Care Medicine, the researchers described how they observed changes in 76 students living on campus at the Fu-Jen Catholic University in Taipei.
"Urban air pollution is a cocktail of pollutants, when you breathe it gets into your body, through the nose, the respiratory tract, then the lungs," said professor Chang-Chuan Chan at National Taiwan University's College of Public Health.
"The different air pollutants observed here can go into your lungs and invoke inflammation effect in days. They can also go directly, without causing inflammation and affect cardiovascular function, like heart rate variability," Chan said in a telephone interview with Reuters.
Chan's team took blood samples from the students, aged between 18 and 25, and monitored their hearts via electrocardiogram (ECG) three times between April 2004 and June 2005.
They then checked to see if there were changes to four indicators that are normally linked to heart disease. The four are inflammation, oxidative stress or damage to tissues and cells, coagulation in blood vessels and autonomic dysfunction or disruption of unconscious bodily functions, such as heart rate, blood pressure and temperature regulation.
"After exposure of between one and three days, we can see these kinds of biological responses in young adults," Chan said. "They hardly can feel the effects, but there are these changes. If your blood is drawn and your heart rate variability is monitored, then definitely there are some changes."
The results of this study are consistent with previous studies, but this is the first time scientists have established a correlation between all four indices and air pollution.
Chan stressed Taipei's air was no different from that in many other cities. The type and amount of air pollutants observed, like suspended particulate of 2.5 and 10 micrometres, nitrate, sulfate and ozone are consistent with those seen elsewhere.
"Even though we use Taipei in this study, these pollutants are commonly experienced by people living in cities ... in China, the amount of their particulate are even higher," he said.
Although such damaging changes were reversible if periods of air pollution were brief, consequences could be dire if exposure to bad air was prolonged. "If the dirty air stays longer, say for months, or years, then there could be chronic exposure effect," Chan said.
"We're worried for people who already have heart disease and air pollution becomes too serious, then this will be a tipping point, leading to adverse effects, including death."