Evaluating contributions of community and indoor PM sources, assessing personal PM exposure, and conducting panel-type epidemiological studies in Asia with research-grade low-cost sensors

The advancement of low-cost sensors provides new opportunities in aerosol research. After calibrating the low-cost sensors in the laboratory and in the fields with research-grade instruments, the accuracy concern of the data quality is resolved. With these research-grade low-cost sensors, PM_2.5 and PM₁ in a time-resolution of minutes can be obtained. This presentation demonstrates the application of research-grade low-cost sensors in source evaluation for community and indoor PM sources, personal PM exposure assessment, and panel-type epidemiological studies which investigates the associations of peak PM exposure and heart rate variability (HRV). HRV is a marker of cardiac autonomic balance; the reduced HRV indicators were found to be associated with an increased risk of myocardial infarction.

 

Cases studies conducted in Asia will be presented. The sensor application on evaluating the contribution of community PM sources was conducted in the Central Taiwan in 2017. The sensor application on assessing indoor PM sources was conducted in the Taipei metropolitan area in the northern Taiwan in 2018. The PM exposure assessment and panel-type of epidemiological studies were conducted in the southern Taiwan and Indonesia in 2018 to 2020. Research-grade low-cost sensors, namely AS-LUNG-O, AS-LUNG-I, and AS-LUNG-P, were used for outdoor, indoor, and personal monitoring in these studies, respectively. The medical-certified RootiRx® sensors were used for HRV monitoring.

 

The results showed that incremental contribution from the stop-and-go traffic, market, temple, and fried chicken vendor to PM_2.5 levels at 3–5m away were 4.38, 3.90, 2.72, and 1.80 μg/m³, respectively. Significant PM spatial variations observed further emphasized the importance of conducting community air quality assessment. For indoor sources, cooking occurred most frequently; cooking with and without solid fuel contributed to high PM_2.5 increments of 76.5 and 183.8 μg/m³ (1 min), respectively. Incense burning had the highest mean PM_2.5 indoor/outdoor (1.44 ± 1.44) ratios at home and on average the highest 5-min PM_2.5 increments (15.0 μg/m³) to indoor levels, among all single sources. In exposure assessment and epidemiological studies, it was found that for a 10 μg/m³ increase in PM_2.5, HRV indicators were reduced 1.3-4.0% in Taiwan subjects in summer and 1.8 -5.7% in Indonesia subjects in dry season. The low-cost sensors used and methodology demonstrated in this presentation can be applied in resource-limited countries to conduct PM and health research.