Cooking, highway pollution linked to high blood pressure

WASHINGTON (AFP) - Women in China who are exposed to pollution from cookstoves and highways face a greater risk of high blood pressure, said a study out on Monday.

The study focused on the role of black carbon, which after carbon dioxide is the second leading human-caused emission driving climate change. It comes from burning wood, coal and fossil fuels.

About half of all Chinese households cook with coal and wood, the researchers said.

The study involved 280 women living in a rural area of northwestern Yunnan province, with an average age of 52. Eighteen per cent were overweight and 4 per cent were obese at the start of the survey.

"The women wore portable air samplers that collected air particulate matter (PM) smaller than 2.5 micrometers, a size commonly associated with adverse health effects, and the samples were analysed for black carbon content," said the study.

Black carbon exposure was linked to higher blood pressure, a leading risk factor for heart disease.

Furthermore, living within about 200m of a highway was associated with a threefold higher systolic blood pressure - the greater of the two numbers that measure blood pressure - than women who lived further from a highway.

"We found an indication that the cardiovascular effect of black carbon from biomass smoke may be stronger if there is co-exposure to motor vehicle emissions," said the study, published in the Proceedings of the National Academy of Sciences.

Reducing such exposure "should lead to a reduction in the adverse health and climate impacts of air pollution."

Previous studies in Latin America have shown that when older women switched from traditional open fire cookstoves to less-polluting chimney stoves, their blood pressure decreased.