China’s air quality is deteriorating

Nature News : Beijing spent the run-up to last year’s Olympic Games claiming that the city’s air had been drastically cleaned up, but those measurements are now being called into question.Using an air pollution index (API) in which a score of 100 or lower indicates air quality as ‘good’, all 17 days of Olympic events in Beijing made the grade. Overall, the city hit an all-time high of 274 good air days in 2008.APIs can be calculated in various different ways; Beijing’s includes measurements of sulphur dioxide, nitrogen dioxide and particles smaller than 10 micrometres across âmdash; dubbed PM10. Controversially, it has not previously used low-level ozone measurements to calculate APIs, and it does not report on the level of particles smaller than 2.5 micrometres across (known as PM2.5). Both ozone and PM2.5 have potential negative impacts on health.Now, Jian Wang of the Chinese environment ministry’s pollution-prevention division has admitted that visibility in eastern cities in China is deteriorating. He says that the cause is ozone pollution and, especially, PM2.5. Related Link Inconsistencies in air quality metrics: ‘Blue Sky’ days and PM10 concentrations in Beijing