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Current Status of Fine Particulate Matter (PM2.5) in Vietnam’s Most Populous City, Ho Chi Minh City

Category: Urban Air Quality

Volume: 19 | Issue: 10 | Pages: 2239-2251
DOI: 10.4209/aaqr.2018.12.0471
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To Thi Hien 1, Nguyen Doan Thien Chi1, Nguyen Thao Nguyen1, Le Xuan Vinh1, Norimichi Takenaka2, Duong Huu Huy3

  • 1 Faculty of Environment, University of Science, Vietnam National University – Ho Chi Minh City, Ho Chi Minh City, Vietnam
  • 2 Graduate School of Humanities and Sustainable System Sciences, Osaka Prefecture University, Osaka 599-8531, Japan
  • 3 Faculty of Food Science and Technology, Ho Chi Minh City University of Food Industry, Ho Chi Minh City, Vietnam

Highlights

  • High PM2.5 levels in the urban atmosphere of HCMC, Vietnam are reported.
  • Temporal and spatial variability of PM2.5 is reported for the first time.
  • A large similarity in PM2.5 levels at different exposed sites is reported.
  • Meteorological conditions influence the monthly PM2.5 variation.
  • Biomass burning of rice straw residues (Mekong Delta) likely elevates the PM2.5 level.

Abstract

This paper provides insights into fine particulate matter pollution in the urban atmosphere of Ho Chi Minh City (HCMC), the most populous city in Vietnam. Fine particulate matter (PM2.5) samples were collected daily at five exposed sites from March 2017 to March 2018. PM10 data (daily) and real-time PM2.5 (hourly) data were recorded concurrently at a roadside site. Daily particulate pollutant levels (i.e., PM2.5 and PM10) were determined using the gravimetric method using an impact sampler, and real-time PM2.5 data were measured using a continuous monitor. The measured PM2.5 concentrations varied from 10.4 to 110.8 µg m–3, with an annual mean of 36.3 ± 13.7 µg m–3. All annual mean concentrations at the exposed sites exceeded the value limits of the Vietnamese standard (25 µg m–3) and World Health Organization air quality guideline (10 µg m–3), indicating high health risk at these sites. Although the sampling sites varied in their exposure levels, they exhibited very strong correlations and low differences in PM2.5 levels. Diurnal variation with a pronounced peak 2 hours after the morning rush hour was observed. This peak is likely attributable to not only primary sources (e.g., traffic-related sources) but also secondary aerosol formation. The urban atmosphere of HCMC was affected by strong local emission sources, as evidenced by the pronounced peak during morning rush hour as well as the significant negative correlation between PM2.5 and wind speed. In addition, monthly PM2.5 levels exhibited remarkable seasonal variability, with the lowest and highest levels observed during the rainy and dry seasons, respectively. However, elevated PM2.5 levels were observed during the months with heavy rains, highlighting the influence of strong emission sources, likely the biomass burning of rice straw residues in the Mekong Delta area.

Keywords

Ho Chi Minh City PM2.5 Urban air pollution Tropical climate


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