Nearly two weeks after a landfill fire started in Navotas City, the Philippine Space Agency (PhilSA) said air quality in Metro Manila ‘has not returned to normal levels.’
PhilSA cited Bureau of Fire Protection (BFP) data showing ‘smoldering conditions’ as of April 23. It also said nitrogen dioxide concentrations over Metro Manila remain higher than on April 6, before the fire broke out.
Nitrogen dioxide is a pollutant produced by burning and is a component of smoke.
The US Environmental Protection Agency said breathing air with high concentrations of nitrogen dioxide can irritate airways in the respiratory system.
It said short-term exposure can aggravate respiratory diseases such as asthma, leading to symptoms including coughing, wheezing or difficulty breathing, as well as hospital admissions and emergency room visits.
Long-term exposure to elevated concentrations may contribute to the development of asthma and potentially increase susceptibility to respiratory infections. People with asthma, as well as children and older adults, are generally at greater risk for the health effects of nitrogen dioxide.
PhilSA said the estimated smoke extent covered Metro Manila and surrounding provinces at 8:45 a.m. on April 23.
Its map indicates nitrogen dioxide concentrations, with darker red colors indicating higher levels.
PhilSA, however, said nitrogen dioxide levels generally decrease throughout the day.
It said this pattern, called a diurnal cycle, may be attributed to atmospheric processes such as easterlies, sea breeze and land breeze, and the dissolution of the inversion layer.
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This is why observations are limited to 8:45 a.m. for daily comparison.