Simulation of air pollution concentration in different urban landscapes using microclimate model | |
| Author | Lekamge, Savinda Heshani Arambawatta |
| Call Number | AIT Thesis no.EV-21-17 |
| Subject(s) | Air--Pollution Particles--Environmental aspects Urban climatology |
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Environmental Engineering and Management |
| Publisher | Asian Institute of Technology |
| Abstract | Vehicular traffic has been identified as a dominant source of PM2.5 in Thailand. Green space was found to be effective in mitigating urban air pollution. Taking Bangkok as the study area, one of the most polluted cities in Thailand, this study quantitatively investigated the effect of vegetation on PM2.5 concentration in Chatuchak Park, an urban park located in Bangkok. The meteorological and PM2.5 sensors were installed at the park, and the ENVI-Met model was run to$simulate$the PM2.5 concentration in study sites. Then, three scenarios including change in weather patterns, change in mode of transport and change in types of vegetation were studied. The site covered with vegetation had higher PM2.5 concentration than other two sites. The highest average concentration was during the morning peak hours from 7.00 am – 10.00 am followed by evening peak hours from 4.00 – 5.00 pm reflecting high traffic emission during rush hours. The average percentage reduction of PM2.5 behind the vegetation barrier in three sites was 34%. Effect of vegetation on meteorological factors was clearly seen near the park border with a hedgerow grown along the border. The order of influence of meteorological factors on PM2.5 concentration was relative humidity>potential temperature> wind speed> wind direction. Comparison in different scenarios showed that change in the wind direction from oblique to perpendicular had no significant effect on PM2.5 as long as presence of a dense hedgerow along the park border. Increase in public transport from 3% to 90% yielded a 77% increase in PM2.5 concentration. Real scenario and one scenario with only hedges and grasses were compared with only grass scenario as the third scenario. Comparison with two scenarios yielded the same percentage reduction of PM2.5 by presence of vegetation concluding that contribution from sparse vegetation with less leaf area density values and higher crown base heights was less to mitigate air pollution from PM2.5. The calculated RMSE, NRMSE, R2 and d values for meteorological parameters and PM2.5 concentration showed that ENVI-met model is suitable in simulating dispersion of pollutants in microclimate environments. Further studies are needed to establish the features that help to reduce exposure and consider guidance or tools to aid in designing parks in terms of plantings, layouts and infrastructure. In addition, the landscape patterns such as secondary roads, size of the parks should be taken into account. |
| Year | 2021 |
| Type | Thesis |
| School | School of Environment, Resources, and Development (SERD) |
| Department | Department of Energy and Climate Change (Former title: Department of Energy, Environment, and Climate Change (DEECC)) |
| Academic Program/FoS | Environmental Engineering and Management (EV) |
| Chairperson(s) | Ekbordin Winijkul; |
| Examination Committee(s) | Visvanathan, Chettiyappan;Srivanit, Manat; |
| Scholarship Donor(s) | Her Majesty the Queen’s Scholarships (Thailand) ; |
| Degree | Thesis (M. Sc.) - Asian Institute of Technology, 2021 |