Date Posted: June 11, 2026

Author/s: Desiree R. Daniega, MD, MHPEd

Objective: COVID-19 has been one of the foci of the daily life of every human being starting in the first quarter of 2020. The implementation of enhanced community quarantine, or in some countries termed as lockdown, was one of the immediate solutions to facilitate mitigation and prevention of the disease’ transmission. One of the impacts seen of ECQ is the healing of the environment. In the Philippines, particularly in the National Capital Region (NCR), initial assessment of its impact was translated into the quality of air before and into the ECQ weeks. This case study used secondary data on air population levels (PM 2.5) and NO₂ levels to present the impact of ECQ on air quality in the NCR.

Methods: The secondary data were requested from the environmental scientists from the University of the Philippines-Diliman. Limited sharing of data and the agreement with their partner organization posed a difficulty in gathering comprehensive historical data.

Results: Both the air pollution levels gathered through the air quality monitoring system and NO₂ levels through the satellite sensor gave a significant drop from two weeks prior to ECQ to two weeks into it. The 3rd week of ECQ gave variable levels both in air pollution (PM 2.5) and NO₂ levels.

Conclusion: The consequences of the implementation of enhanced community quarantine in the NCR, primarily the enforced public transportation system halt and reduced human mobility and activities, have significant impact on air quality as reflected in the reduced air pollution levels and NO₂ levels two weeks into the ECQ.

Keywords:
Enhanced Community Quarantine, COVID-19, air quality, air pollution, particulate matter, nitrogen dioxide level