Bureau of Customs

Simplified and Effective Air Monitoring Programs in the Philippines

Date posted: 
Nov 13 2008

The practice aims to provide cost-effective air monitoring program, especially in the scenario of budget and resource constraint.

Responsible Party: 
Enforcement Agency
I. Objectives or Impact: 

The practice aims to provide cost-effective air monitoring program, especially in the scenario of budget and resource constraint.


Air pollution monitoring

II. Description of the Good Practice (Outputs): 

Ambient air quality standards have averaging times of ranging, from one hour for carbon monoxide and ozone to one year for sulfur dioxide and nitrogen oxide. However, commercial manufacturers and distributors of air pollution monitoring equipment aim to sell expensive real-time monitoring equipment, linked to the Internet where people could see the trends of air quality. While the instantaneous presentations of the results could mesmerize the public and decision-makers unfamiliar with technical issues on air quality monitoring, the prohibitive cost of such system (US$300,000 to 700,000 per monitoring site) makes the usefulness of the monitoring data of little value to actual policy making. Also, the monitoring stations are limited in number and often sparsely located. The operating and maintenance cost of the monitoring stations is very expensive, ranging from $20,000 to 50,000 annually. Real time air quality monitors then often serve as promotional display, often located in the middle of parks and places of thick vegetation, negating its main and actual purpose.

However, with budget constraints, far more cost-effective options are available. In the last 20 years, passive samplers have been developed and used satisfactorily. Compared with real time monitors, passive samplers are cheap, costing from $5 to 10 per sample. Instead of one sample for one urban area, the air quality could be monitored at a hundred sites at a fraction of the annual and operating cost of an open path sampler. One drawback of passive samplers though is the frequent need to take, remove, and change the sampler depending on the averaging time of the pollutant.

Passive samplers were shown to be very effective. The World Bank and Asian Development Bank used the passive sampler in monitoring the sulfur dioxide concentration in its RAINS-ASIA program. The monitoring results were used to calibrate a complex acid rain regional model and development regional strategies. In the past, the cost of passive samplers and analysis was much higher, by as much as a factor of three as the equipment for analyzing the samples were in the early stages of development and very few laboratories in the world have the capability. The samplers were sent to Europe for analysis. Today the equipment for analysis could be purchased at around $50,000.

III. Outcomes or Results: 

The World Bank and the Asian Development Bank used the passive samplers effectively in its acid rain studies in Asia. The monitoring results were used to calibrate the RAINS-ASIA model and develop mitigation measures.

IV. Essential Elements for Success: 

Policy Framework: Enabling Policy, Regulation, Inter-agency/Multiparty Agreements

There is a need for the development of a strong and well-defined air pollution monitoring policy framework in order for the technical personnel to resist the strong pressure from expensive air pollution monitoring equipment salesmen. The monitoring stations locations have to be defined in terms of area, population density and economic activity. It should be realized that one or two sampling stations do not give any meaningful picture of the air pollution trend of the city.

Human Resources and Skills

In the World Bank and Asian Development Bank study, the nearby residents did the collection and replacement of the passive samplers.  They were given one hour training on the placement, removal and storage of the samplers. Laboratory equipment for analysis would be advantageous if there are more than a hundred samples to analyze every month. A skilled chemist is required to run the equipment.

Material and Resources

Supply of passive samplers and analytical equipment is needed. Otherwise the sampler could be mailed to the nearest laboratory with the proper equipment and analyst as done in the World Bank –Asian Development Bank study.

Institutional Support

Support from scientific community and NGO is needed in order for the environmental management agency to withstand the pressure from salesmen to buy expensive monitoring equipment.

V. Further Information: 

References and Publications:

World Bank publications on Acid Rain

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