Performance evaluation of multiple particulate matter monitoring instruments under higher temperatures and relative humidity in Southeast Asia and design of an affordable monitoring instrument (ManPMS)

Abstract

The rapid industrialization of nations in Southeast Asia (SEA) has led to a decline in these countries’ air quality, including high levels of particulate matter (PM). Monitoring these air pollutants is crucial to understanding the pollution status of the area and developing management plans for improvement. The metrological conditions in the region present challenges as high temperature and high humidity have been known to cause errors in the measurements. This study investigated the performance of five PM monitoring instruments with different working principles. The air temperature was mostly over 25 °C with relative humidity usually remaining above 80%, which is typical of SEA weather. Measurements from all instruments had good correlations with each other as their linear regressions yielded slopes of 1 ± 0.15 and R² > 0.65. Moreover, this study found that depending on the chosen reference instrument, not all factors affect the devices equally. In particular, using Partisol as a reference, the PM_2.5 concentration, air temperature, and relative humidity had less impact upon the relative bias level compared to using Leckel as a reference. In addition, the high cost of monitoring instruments also poses financial constraints on how many monitoring stations can be deployed. To tackle this issue, this study presents ManPMS whose design is based on that of the USEPA Title 40 Part 50 with slight modifications. The cost to manufacture and assemble the instrument was only 2/3 the price of a typical instrument with similar performance.

Keywords:

• Air quality
• impact of relative humidity
• impact of temperature
• reference gravimetric method
• particulate matter
• performance evaluation

Acknowledgements

The authors of this study would like to thank their colleagues at their institutions for all the contributions and support in designing, fabricating, and testing.

Disclosure statement

The authors of this study declare that they have no conflicts of interest.

Author contributions

Nam Duong Thanh was the main coordinator and oversaw the entire study. Hoa Tran Thi and Trung Nguyen Quang conducted all the procedures relating to the reference gravimetric method instruments in the laboratory. Huy Nguyen Van, Giang Hoang Nguyen, Quyet Nguyen Huu, and Tung Son Tran assembled the ManPMS and the activity in field.

Data availability

All data presented in the paper are available for research purposes upon request.

Additional information

Funding

The funding for this study was received from the VAST under grant number CT0000.11/21-23 for the “Research, manufacture and incorporate particulate matter monitoring instrument (PM₁₀, PM_2.5) for ambient condition” project.