Air pollution, can we reduce the impact of cars on urban air quality?

Air pollution in Delhi

Air pollution in Delhi

In January 2016, Delhi, India, improved air quality on its streets when it conducted a 2-week air pollution reduction experiment, with private cars allowed on the streets only on alternate days, depending on license plate numbers.   The idea is not new and has been tried elsewhere (Paris and Rome) but I guess its novelty (“who’d have thought” brigade) to the USA explained why it made The New York Times!

Last year, it was all headlines about Bejing [China] and the air quality citizens had to deal with. However it would seem that actually Beijing’s levels of PM10 (particulate matter up to 10 micrometres in size), a measure of air quality, decreased by 40% from 2000 to 2013, whereas Delhi's PM10 levels have increased 47% from 2000 to 2011.

Delhi's PM10 levels are nearly twice as much as in Beijing, and it has the worst PM 2.5 levels of 1600 cities in the world. Thus the need for the license plate experiment. In a BBC article, you can read more about the reasons “Why Delhi is losing its clean air war” and discover the varied & innovative measures China has taken to ameliorate motor car use.

No doubt spurred on by Delhi’s experiment, a health journalist in Bangladesh alerted the HIFA forum to the equally bad situation in India’s neighbour, Bangladesh.

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You say tomato, I say cardioprotective antiplatelet factor

Several studies have indicated that tomatoes may help reduce the chances of heart disease (see for example "Organic tomatoes – better for your heart?"). But how might this work? A paper in CAB Reviews looks at the evidence that proteins which prevent the clotting of platelets may play a key role.

Platelets play a vital role in preventing excessive blood loss by clotting at the site of an injury. However, platelet aggregation is a central step in heart disease, including heart attacks and unstable angina, says Asim Duttaroy, from the Faculty of Medicine, University of Oslo. While aspirin shows some activity in stopping this aggregation, its action is relatively weak, and it can cause gastrointestinal disturbances and bleeding problems in some patients. Studies directly on platelets show that tomato juice and kiwi fruit juice are both potent at preventing platelet aggregation.

Researchers went further and tried to identify which components in the tomato juice had the biggest effect on platelets. Besides water, most of the juice was made up of soluble sugars, which had no effect, but once those had been removed, different components had different effects on clotting. They showed that the sugarless extract supplied in orange juice could reduce platelet aggregation in humans, 3 hours after drinking the equivalent of 6 tomatoes-worth.

The studies also showed that people who had known markers for heart disease were more sensitive to the extract than those who did not. While there is much still to be confirmed by more detailed study, Duttaroy says “Consumption of such tomato extracts as a food supplement could benefit public health by helping maintain platelets in an inactivated state and reducing the risk of thrombotic events mediated by platelet activation”. Which is good news, as you could enjoy the health benefit even if you didn’t fancy eating 6 whole tomatoes.

Cardiovascular health benefits of tomatoes” by Asim K. Duttaroy appears in CAB Reviews: Perspectives in Agriculture, Veterinary Science, Nutrition and Natural Resources.