As people take time off school and work on the 70th anniversary of the founding of the PRC, hot weather and wind expected to blanket the city
The Marine Department on Monday said smog and haze had reduced visibility to two nautical miles, or about 3.7km. The public holiday for national day, and the following day are set to experience heavy smog, with hot weather and wind leading to serious air pollution , the city’s environmental watchdog said on Monday.
The Air Quality Health Index has been “very high” since Thursday, according to the Environmental Protection Department, but recent sunshine has caused ozone and other particulates to form quickly over the Pearl River Delta.
High levels of ozone have led to the formation of nitrogen dioxide, increasing the chances of respiratory problems, particularly in urban areas, the department said. The smog warning could further complicate National Day on Tuesday, when a number of outdoor rallies for and against the government are expected.
Cheng Chi-man, a family doctor and vice president of the Hong Kong Medical Association, said the recent use of tear gas to quell anti-government protests would also affect air quality.
“Most healthy people are not affected by background pollutants in the environment,” he said. “Tear gas, however, is designed for immediate effects and people with existing nasal or eye allergies could suffer even more.”
The Air Quality Health Index is a scale of 1 to 10 and 10+, with five health risk categories: low, moderate, high, very high and serious. The system is used to alert the public to short-term health risks of air pollution.
“With a health risk category in the ‘very high’ range or above, children, the elderly and persons with existing heart or respiratory illnesses are advised to reduce physical exertion and outdoor activities to a minimum or avoid such activities,” the department said in a statement.
At 2pm on Monday, the index at three of the 13 general monitoring stations – including Central, Tung Chung and Tuen Mun – had reached the “serious” level. The remaining 10 stations were at “very high” levels. Roadside monitoring stations in, Causeway Bay and Central were also at “serious”, while a roadside station in Mong Kok was “very high”.
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The Marine Department on Monday said hazy conditions restricted visibility of less than two nautical miles, or about 3.7km, and issued a reminder to ships to exercise extreme caution and travel at safe speeds while navigating local waters.
Pollution levels are expected to drop when an east wind comes to the coast of Guangdong province over the weekend and early next week, according to the Environmental Protection Department.
The Hong Kong Observatory has forecast hot and hazy weather for the next few days, with clouds and a few patches of rain over the weekend.
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Professor David Hui Shu-cheong, an expert in respiratory medicine at Chinese University, said air pollution could worsen the conditions of patients suffering respiratory illnesses.
“Air pollution increases the risk of exacerbation in patients with existing asthma or chronic obstructive pulmonary disease,” Hui said. “Air pollutants cause more inflammation and swelling of the airways leading to more airflow obstructions.”
Local research has found that increases in the levels of air pollutants correspond to increases in hospital admissions for residents suffering from asthma and or other respiratory ailments.