Chapter 5: CONCLUSION AND RECOMENDATION
5.3 Limitations and Recommendations for Future Study
Several key limitations and recommendations for future studies are outlined below.
(a) A major limitation of this study is that PNC data coverage is low due to an instrumental failure. While it was planned to collect about 10 day-visits of PNC and PM2.5 data per site, covering summer and winter, PNC data collection in summer did not happen due to an instrumental failure. A condensation particle counter (CPC) was used to collect PNC measurements, which is a costly instrument. The CPC was obtained through a collaborative research work with Carnegie Mellon University. Once CPC failed, it was not possible to repair it due to COVID-19 pandemic and financial constraints. A future effort should collect data in summer and winter conditions. Also, it is recommended to collected 10-15 days of short-term data at each site covering a range of meteorological and temporal attributes to obtain a robust estimate of mean concentration. Also, a future study may consider collecting data at a greater number of sites.
(b) Low-cost sensor needs comprehensive local calibration under a range of environmental condition that was not possible in this study. The low-cost PM2.5 sensor used in this study was compared with the data from US Embassy PM2.5 monitor. A reasonable agreement was found. However, a comprehensive long-term colocation against a reference monitor is recommended in a future study.
(c) The scope of the study was limited within data collection and quantification of intra- urban spatial variability. Some effort is made to inferring important factors that drive the spatial patterns. Future study should put comprehensive effort in identifying various modifiable factors that drive the spatial patterns. This will help in pollution mitigation plan.
(d) The scope of the study was limited to sampling within Dhaka city. In general, the findings in this study may not represent the other metropolitan cities in Bangladesh. Future studies should conduct measurements in other cities to assess how this study's findings represent for other cities in Bangladesh.
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