Ozone pollution levels in Shanghai 1.5 times higher than WHO’s recommended limit
Gas now presents bigger health threat to urban residents than PM2.5 particles, but its complex formation makes it much harder to combat
Ozone pollution in Shanghai over the past two weeks has reached levels 1.5 times higher than the WHO’s recommended limit.
The poisonous gas has replaced PM2.5 pollution – particles small enough to enter the lungs – as the biggest threat to the health of residents in several major mainland cities. But experts say ozone pollution, with its complicated formation process, is more difficult to combat than fine particles.
Shanghai saw elevated levels of ozone pollution for 12 straight days, from July 25 to Wednesday, with a peak reading of 246 micrograms per cubic metre recorded on Tuesday, according to the city’s Environmental Monitoring Centre.
The World Health Organisation recommends a limit of 100 micrograms per cubic metre (µg/m³). Exposure to excessive amounts can cause breathing problems, lung disease and trigger asthma.
Ozone was the major air pollutant for 60.5 per cent of all polluted days in the second quarter, compared with 16.9 per cent for PM2.5, the newspaper reported, citing sources at the provincial Environmental Protection Department.
During the same time last year, the figures were 34.1 per cent for ozone and 32.2 per cent for PM2.5.