Improvement of GPS-attached Pocket PM2.5 Measuring Device for Personal Exposure Assessment.

Assessment of personal exposure to particulate matter with an aerodynamic diameter less than or 2.5 µm (PM2.5) is necessary to study the association between PM exposure and health risk. Development of a personal PM2.5 sensor or device is required for the evaluation of individual exposure level. In this study, we aimed to develop a small-sized, lightweight sensor with a global positioning system (GPS) attached that can measure PM2.5 and PM10 every second to assess continuous personal exposure levels. The participants in this study were apparently healthy housewives (n = 15) and university female teaching staff (n = 15) who live in a high PM2.5 area, Yangon, Myanmar. The average PM2.5 exposure levels during 24 h were 16.1 ± 10.0 µg/m3 in the housewives and 15.8 ± 4.0 µg/m3 in the university female teaching staff. The university female teaching staff showed high exposure concentrations during commuting hours, and had stable, relatively low concentrations at work, whereas the housewives showed short-term high exposure peaks due to differences in their lifestyles. This is the first study to show that a GPS-attached standalone PM2.5 and PM10 Sensor [PRO] can be successfully used for mobile sensing, easy use, continuous measurement, and rapid data analysis.

Preliminary monitoring of concentration of particulate matter (PM2.5) in seven townships of Yangon City, Myanmar.

BACKGROUND: Airborne particulate pollution is more critical in the developing world than in the developed countries in which industrialization and urbanization are rapidly increased. Yangon, a second capital of Myanmar, is a highly congested and densely populated city. Yet, there is limited study which assesses particulate matter (PM2.5) in Yangon currently. Few previous local studies were performed to assess particulate air pollution but most results were concerned PM10 alone using fixed monitoring. Therefore, the present study aimed to assess distribution of PM2.5 in different townships of Yangon, Myanmar. This is the first study to quantify the regional distribution of PM2.5 in Yangon City. METHODS: The concentration of PM2.5 was measured using Pocket PM2.5 Sensor (Yaguchi Electric Co., Ltd., Miyagi, Japan) three times (7:00 h, 13:00 h, 19:00 h) for 15 min per day for 5 days from January 25th to 29th in seven townships. Detailed information of eight tracks for PM2.5 pollution status in different areas with different conditions within Kamayut Township were also collected. RESULTS: The results showed that in all townships, the highest PM2.5 concentrations in the morning followed by the evening and the lowest concentrations in the afternoon were observed. Among the seven townships, Hlaingtharyar Township had the highest concentrations (164 ± 52 µg/m3) in the morning and (100 ± 35 µg/m3) in the evening. Data from eight tracks in Kamayut Township also indicated that PM2.5 concentrations varied between different areas and conditions of the same township at the same time. CONCLUSION: Myanmar is one of the few countries that still have to establish national air quality standards. The results obtained from this study are useful for the better understanding of the nature of air pollution linked to PM2.5. Moreover, the sensor which was used in this study can provide real-time exposure, and this could give more accurate exposure data of the population especially those subpopulations that are highly exposed than fixed station monitoring.

Evaluation of basic characteristics of a semiconductor detector for personal radiation dose monitoring.

Real-time radiation dose management is important because staff members working in interventional radiology may be exposed to relatively high doses of primary and scattered radiation from the body of a patient. In this study, we investigated the dependence of energy and dose rate of the commercially available semiconductor detector named Pocket Geiger (POKEGA) for personal monitoring in diagnostic X-rays. In the energy-dependence study, a suitable metal filter and the threshold level were examined for energy compensation using a Monte Carlo calculation code. Moreover, the energy dependence of the POKEGA with an optimal metal filter was compared with that of commercially available active personal dosimeters (APDs). With an aluminum filter, the difference of the ratio of the absorbed dose of silicon to that of air was ±7% for a tube voltage of 70-110 kV and a cutoff energy of 23 keV in the calculation. The energy response of the APDs, except the PDM-122B-SHC and the POKEGA, met the required JIS standard from 50 to 110 kV. In the dose rate-dependence study, a high linearity was observed up to 2.2 mGy h-1 using the POKEGA with an aluminum filter.