EXPLAINER: How does haze affect your health?

Wildfires in Indonesia have burned about 200,000 hectares of land, producing thick haze that has spread to neighboring countries, including the Philippines.

Indonesia has been working to contain the fires, but the prevailing El Niño phenomenon has made firefighting efforts more difficult. Smoke has blanketed several parts of the country.

According to a GMA News Feed report, the haze was observed in several parts of Metro Manila, CALABARZON and MIMAROPA.

In the National Capital Region, the air quality was classified as “very unhealthy” and “accurately unhealthy,” according to the Department of Environment and Natural Resources–Environmental Management Bureau (DENR-EMB).

What is haze?

Haze is an atmospheric phenomenon in which fine particulate matter accumulates in the air. This includes PM2.5, or particles measuring 2.5 micrometers or smaller in diameter—about 30 times smaller than the width of a human hair.

How is air quality measured?

Experts measure the concentration of PM2.5 in the air and use it to determine the air quality category under the Air Quality Index.

The index has six categories: green for good, yellow for moderate, orange for unhealthy for sensitive groups, red for unhealthy, purple for very unhealthy, and maroon for hazardous.

How does PM2.5 affect the body?

Unlike larger particles such as dust, PM2.5 is small enough to bypass some of the body's natural defenses and penetrate deep into the respiratory system. These particles can reach the air sacs in the lungs and cause inflammation.

Unlike larger particles such as dust, PM2.5 is small enough to bypass some of the body's natural defenses and penetrate deep into the respiratory system. These particles can reach the air sacs in the lungs and cause inflammation.

When air quality reaches the purple or “very unhealthy” level, exposure can pose health risks, particularly to sensitive groups. Fine particles can cause coughing, throat irritation, wheezing and difficulty breathing.

Exposure to high levels of PM2.5 can also worsen asthma and other existing lung conditions.

The particles can also enter the bloodstream and affect other parts of the body. Prolonged or high-level exposure to PM2.5 has been linked to cardiovascular problems, including an increased risk of heart attack and stroke.

Who is most vulnerable to haze?

The DENR-EMB reminded the public to limit outdoor activities in affected areas, especially people who are more sensitive to air pollution, including children, older adults, and those with lung or heart conditions.

The DENR-EMB reminded the public to limit outdoor activities in affected areas, especially people who are more sensitive to air pollution, including children, older adults, and those with lung or heart conditions.

For those who need to go outdoors, wearing a properly fitted N95 or equivalent respirator can help reduce exposure to fine particles.

The public is also advised to stay informed about air quality conditions and follow guidance from reliable government sources.— Jean Mangaluz with research from GMA DigiLab/MCG, GMA News