Figure 4. Wind Vector Superimposed in Northern Domain of the ADM Study Area

OBSERVATIONS AND CONCLUSIONS

The air quality in Metro Manila varies depending on location and time of day or period of the year; Mobile sources contributes largest fraction to air quality.

Higher concentrations in the north are partly explained by the wind regimes such as during the Habagat season shown in Figure 4. Winds over Manila Bay are from the southwest, while winds near Laguna Lake are from the southeast. The converging winds help confine pollutants inside Metro Manila, and allow emissions from the south to add to those on the north. Additionally, industries in the North also contribute to air pollution.

Fuel, Vehicles, Topography and meteorology are the same in Metro Manila. This raises the question as towhy air quality vary in different sectors. Also, it is notable from Figure 2 that the air quality vary over a 24-hour period when in fact the same fuel and type of vehicles are involved.

AQM STRATEGIES

GENERAL FRAMEWORK

• The ADM Study suggests the adoption of a simple paradigm

"LOCAL SOLUTIONS TO LOCAL PROBLEMS"

There are good reasons to believe that local traffic impacts significantly on air quality of a particular area; and explains partly variations in air quality over different sectors of Metro Manila and over a 24-hour period for a specific site.

• The idea of regional “Fuel Harmonization” long advanced by some local and regional sectors deserves a much closer evaluation. The ADM study points to local problems and circumstances not experienced in other countries. Further the institution of various (12) separate air sheds in the country connotes that even in a small country different approaches to AQM in various parts (airsheds) of the country apply.

• Fuel Quality

Restricting parameters in fuel quality should distinguish between the "nice" to have and the "compelled"-to-impose specifications. To illustrate the Phl ban on lead and restrictions in MTBE in gasoline was brought by compelling health reasons. The reductions in Sulfur concentrations in gasoline and diesel fuels were occasioned by the requirements of vehicle manufacturers for compatibility with OBDs (On Board Devices) that regulate emissions of conventional pollutants. The Philippine fuels are compliant with standards for these parameters.

"Euro" Fuels, Biofuels and Organic Pollutants

Robust discussions continue relating to "euro" fuels, organic pollutants and biofuels. Specifications relating thereto may impact on air quality and is expected to create definite implications on fuel cost and reliability with attendant impacts on the economy.

Strictly "Euro" standards refer to emission limits of the exhausts of vehicles, measured in weight pollutant per distance travelled by vehicle while air quality is measured in terms of concentration of pollutants in the ambient air, measured in weight of pollutant per volume of air. It is also notable that Euro standards e.g. as prescribed in the 1999 Philippine Clean Air Act were determined before the introduction of biofuels. The true measure of air quality is the concentration in the ambient air which is the parameter used in this ADM study.

Biofuels are recognized to result in lower fuel efficiency in terms of weight pollutants per distance travelled. Biodiesels are reported to result in cleanerexhaustgases. Bioethanols are suspected to cause aldehyde concentrations in the air. The value of an Air Dispersion Modeling is that it shows the overall impact in terms ofconcentrationsof pollutants in the ambient air as influenced by various factors among which is fuel quality.

Among the organic pollution parameters are aromatics, olefins, Polycyclic Aromatic Hydrocarbons (PAH). The challenge to regulators is how the concentration of such organic substances in the fuel will ultimately influence the quality of ambient air recognizing that these organics are burned in the engines. The products of combustion are carbon dioxide and water which are harmless to human health.

• Traffic

Without any doubt traffic is a big factor contributing to air quality. The Phl government recognizes the seriousness of traffic congestions in the urban areas from a holistic social impact. A shift from cars to mass transit should be a prime consideration in the master plan. Resolving the problem cascades into the improvement of air quality.

Traffic is integrated in this Study in the generation of the Air Dispersion Maps.

• Regulatory Aspects

Among the regulatory aspects that the study suggests are:

• Further review of the air monitoring stations in terms of number and location. It appears that the stations could be focused in the critical areas. (Refer to Figure 2) .
• Strengthening of the MVIS protocol and implementation, as mentioned in a meeting of the NCR Airshed Board.
• Traffic regulations and enforcements. This include non – contact apprehensions and the expanded use of CCTV in traffic monitoring.
• Effective Monitoring Schemes. On the paradigm "You Cannot Manage What You Do Not Know" monitoring serves as an effective tool to develop the appropriate management actions.

The EMB NCR has recently set up Operations Center for AQM, the photographs shown below:

Online/Real time continuous monitoring of PM10/PM2.5 in twelve (12) stations in Metro Manila provide both immediate and medium term basis for action plans.

Photographs of the NCR Operations Center