Context vital in interpretations of air quality data

Addressing air quality issues in cities throughout the Philippines has in recent years become a priority for both the Department of Environment and Natural Resources and a growing number of city administrations, many of which are taking steps to reduce harmful pollutant emissions and improve data gathering and assessment.

In the 20 years since the passing of the Philippine Clean Air Act, which provides a framework for managing air quality, air pollution levels in major cities still exceed national ambient air quality standards and World Health Organization guideline values. Air pollution is still among the top causes of death and disability in the country, with PM2.5 contributing to 44,389 deaths in 2016 alone, according to the Health Effects Institute. While alarming, this should not undermine national and city governments’ commitment and pollution-reduction efforts; rather, it underscores the complexities involved in improving air quality in disparate and diverse urban contexts throughout the country, and highlights the need for targeted city-level mitigation policies and interventions that address the specific challenges being faced.

Air quality is defined by a number of variables, such as pollution sources, climatic conditions, temperature, humidity, geography and the individual characteristics of different urban landscapes.

Air quality data is influenced by the mechanics of monitoring, such as monitoring location, the number and placement of monitoring sites, the frequency of monitoring, the percentage of data captured per site and, importantly, the accuracy of the instruments used. Isolated air quality measurements are not necessarily reflective or indicative of a city’s or cities’ overall state of air quality.

Put simply, air quality as a whole is more than the sum of its parts, and its mitigation must be based on individual cities’ unique situations and the interactions between different emission sources to ensure targeted interventions are implemented.

The sheer scale of the air pollution problem and the multiplicity of emission sources present numerous cross-sectoral challenges in effectively managing air quality. Emission sources, the availability of monitoring equipment, and management and technical capacity differ widely from region to region and city to city. Accurate data and data interpretation are vital in guiding national and city-level efforts in the formulation of tailored policies and strategies aimed at reducing air pollution.

Clean Air Asia is presently assisting a number of Philippine cities in improving their air quality within a strategic air quality management framework, and has developed a range of tools to help city officials assess urban air quality and their attendant air quality management capacity, enabling them to develop roadmaps to cleaner air. Those tools include the Clean Air Scorecard and the Guidance Framework for Better Air Quality in Asian Cities. The Clean Air Scorecard is an assessment tool that scores a city’s air quality, and provides an objective assessment of a city’s air quality status, management practices, and policies that help guide the development of appropriate mitigation policies and plans. The Guidance Framework provides cities and countries with the knowledge and direction needed to effectively reduce air pollution based on six identified priority areas of concern: Ambient Air Quality Standards and Monitoring, Emissions Inventories and Modeling, Health and Other Impacts, Air Quality Communications, Air Quality Communications, and Governance. In addition, our “Air Quality in Asia: Status and Trends 2018” report is aimed at informing decision-makers about sound, science-based policies and avoiding misinterpretations of data.

We commend the efforts of all cities that are proactively addressing their respective air quality challenges and are working hard to better protect the health of their communities and those most at risk from the health impacts of air pollution, and in so doing demonstrating what cities can do when air quality interventions are undertaken holistically.

For more information, contact Dang Espita, Clean Air Asia Senior Air Quality Program Coordinator at