Ahead Online: Earth Talk

Metro Manila Air Quality:
Killing You Softly

By Marian C. Martin
Photos by Manny Fernandez

Breathing is a sign of life. But in Metro Manila, it can cause death. The air that we breathe can now also kill us. Metro Manila residents have long bemoaned the blanket of dust, soot and dangerous gases that hangs ominously over the city.
The Asian Development Bank financed a study called the Metro Manila Air Quality Improvement Sector Development Project in 1998 to study the city’s pollution problem. The aim of the program is to improve the air quality in the Metro Manila air shed. The study harnessed the combined efforts of the Department of Environment and Natural Resources, Health, Public Works and Highways, Transportation and Communications and the Metro Manila Development Authority. The study conducted a comprehensive baseline research study to determine the effects of pollution to the health of the residents.

A pall of soot-laden air chokes Metro Manila.

o keep tabs on air quality in Metro Manila, Cesar Siador Jr., Chief of Air Quality Management of the DENR, says that the DENR deployed nine monitoring stations and six automatic monitoring stations at strategic areas. These monitor the levels of concentration of six major pollutants. Air samples are taken every eight hours and brought to the DENR laboratory in Quezon City for analysis. “The nine manual stations monitor sulfur dioxide and particulate matter (PM₁₀). The automatic stations monitor sulfur dioxide, oxides of nitrogen, photochemical oxides like ozone, carbon monoxide and lead.” The DENR follows guidelines established by the World Health Organization that specify what levels of pollutants are acceptable.
Surprisingly, Siador reveals that the pollution picture isn’t as bad as people would think. “For the gaseous pollutants, we are within the guideline values of the WHO. We are more polluted than other cities in only one parameter: particulate matter. Particulate matter is the minute matter that floats in the air.” He points out that even the high concentration of PM10 is still within acceptable limits over a 24-hour period. The highest it has ever reached is 213.55 micrograms/normal cubic meter. The safe level is 230 micrograms/NCM.

iador discloses that the pollution in Metro Manila is worst in the north, particularly in Valenzuela, Bulacan. The air quality improves significantly the farther south one goes. By the time you get to Sucat, Parañaque, he notes, the air quality is already fair. Over the year, air pollution is worst during the dry season. “We are happy when it rains because it naturally cleans the environment. But in some areas, like EDSA, where traffic is heavy year-round, we have high concentrations of PM₁₀ even during the rainy season.” He says that during the day, pollution peaks between 6 a.m. and 10 a.m. and again between 1 p.m. and 7 p.m. Another peak period follows in the evening, between 10 p.m. and midnight.
The DENR has used its monitoring-stations data to issue periodic warnings to the public or to aid legislation. Siador notes that on the strength of the DENR’s recommendation, the government banned open fires and the burning of rubber tires in Metro Manila. He recalls that data collected by the DENR in 1993 and 1994 on the levels of lead in the atmosphere led to a campaign to reduce lead emissions. The result was the Clean Air Act which, among other things, obligated industry, civil society and the government to reduce the lead content in gasoline and to start making available unleaded gasoline. He reports that by February 1994, lead concentration in the air plunged to 1.29 micrograms/NCM. It has been falling every year since then. In 2000, lead went down to .04 microgram/NCM. “We can now say that Metro Manila is lead-free. In January this year, the lead content went down to as low as .01 microgram/NCM in some parts of Metro Manila.”

Diesel engines may have beaten the rap on lead poisoning but they're guilty
of a whole plague of pulmonary diseases.

Heavy air pollution is a major cause of pulmonary ailments in the metropolis.

Buses with old, poorly maintained diesel engines are the heaviest polluters.

r. Desiree Narvaez, Chief of the Environmental and Occupational Health Office of the DOH believes that the public should remain alert to the impact of pollution on health. She says that the DOH made a baseline health profile under the Metro Manila Air Quality Improvement Sector Development Project involving several barangays in Metro Manila. She warns of incidences of respiratory diseases like asthma, bronchitis, coughs, colds and chromic obstructive pulmonary disease. The study says there’s a rise in morbidity rates in Malolos, Bulacan and Navotas which could be attributed to air pollution there.
The study indicates that the average hourly levels of PM₁₀are indicative of unhealthy conditions for children, the elderly and those already suffering from asthma and respiratory diseases. The study states “exposure to lead indoors is still important considering that lead levels are measured in three-fourths of the study households. This exposure partly contributed to the blood levels determined among the study children.” The study also mentions the levels of benzene indoors. The study states “Available data indicate that a significant proportion of six- to ten-year-old children in the study households exceeded the WHO recommended limit for children which is 20 micrograms/dl.”
Dr. Narvaez says a high level of lead in the blood can affect the development of the children’s central nervous system (CNS) and their cognitive functions, perhaps even decrease their IQs. It can also give rise to behavioral problems. “Bad” ozone damages lung tissue. Sulfur dioxide aggravates existing respiratory and cardiovascular disease. Carbon monoxide reduces the capacity of blood to transport oxygen from the lungs to the different tissues. Nitrogen dioxide irritates the lungs and lowers resistance to respiratory infections. PM₁₀aggravates existing heart and lung disease. Hydrocarbons, such as benzene, affect the blood and the CNS, causing dizziness or headaches. More disturbing, they also depress the immune system.

r. Narvaez says residents can protect themselves in a number of ways: by installing air-conditioning in their homes, for instance, or by wearing masks if they are passing through heavily polluted areas. “People can avoid smoking indoors. When you are indoors you can close the windows if you live in a polluted area or just have a little ventilation at night.”
But pollution, it seems, can only be reduced by a major effort by the government and the public. Siador says the Clean Air Act has been implemented and he hopes it will reduce pollution in Metro Manila. The general public, however, will do well to prod the government to adopt a more aggressive stance towards the quest for cleaner air.