MODIS used to build map of open burning hot spots, preliminary assess about PM 2.5 fine dust concentration in Vietnam

Experts from the Center for Agricultural Research and Ecological Studies (CARES) at Vietnam National University of Agriculture (VNUA), based in Ha Noi, have used Moderate Resolution Imaging Spectroradiometer (MODIS) and Visible Infrared Imaging Radiometer Suite (VIIRS) instruments to build maps of straw open burning hot spots and develop a preliminary assessment of Vietnam's PM 2.5 fine dust concentration.

In Vietnam, the use of MODIS is widely applied in agriculture, such as mapping the spatial distribution of rice paddies or other land use types, quickly assessing changes in water resources, salinity, and damage to agricultural land due to floods, and analyzing rice cultivation areas affected by salinity and floods.

Researchers used MODIS to map the cropping patterns in Vietnam

Under the cooperative project with the Global Alliance On Health and Pollution (GAHP) and the Vietnam Association for the Conservation of Nature and Environment (VACNE),  a group of experts from the Center for Agricultural Research and Ecological Studies (CARES) under the Vietnam National University of Agriculture, the Northern Center for Environment Monitoring (NCEM) under the Environmental Pollution Control Department, Ministry of Natural Resources and Environment and the Center for Development of Community Culture and Civilization (CDC3) have employed remote sensing data together with available secondary data, such as the national land use map,  meteorological data and air quality data from on-ground monitoring stations in the 2012-2022 period, for assessment of environmental risks. The works are aimed to identify hot spots for open burning every year across the country, isolate hot spots due to open burning of agricultural by-products,  and conduct a preliminary assessment of the concentration and distribution of PM2.5 fine dust levels and open burning activities in agriculture.

The research team has spent much time processing all satellite data sources and authenticating access points. The team has so far developed the land use maps, the open burning hot spot maps in Vietnam in 2012, 2016, and 2020, the open burning hot spot map by regions, the open burning area maps by hot spots in ecological regions in 2012-2021; the agricultural by-product open burning map in the Mekong Delta and Red River Delta in 2012 and 2021; and the monthly average PM2.5 dust concentration distribution maps in 2021.

The team has determined that most of the agricultural open burning area occurs on wet rice land, especially in the western Mekong Delta region. The team noted that MODIS and VIIRS data provide relatively good information about the location of open burning on rice fields of at least 2,500 m2. However, it is more challenging to determine the open burning area in the Red River Delta because rice cultivation fields are small and fragmented, usually only 360-2,500m2. Another finding is the use of MODIS only cannot determine the burning open regions due to the difference in shooting time (10:30 a.m. and 1:30 p.m.), as the straw burning time in a day varies, depending on each household.

The research team's biggest challenge is a shortage of data sources. There is still a lack of good air pollution propagation models and ground station data on measuring air quality indicators in Vietnam.

To map fire areas, the research team used MODIS and VIIRS data via The Fire Information for Resource Management System (FIRMS) and MCD64A1 products provided by NASA, resulting in both open-burning hotspots and burned areas maps of 2012, 2016, and 2021.

With much time and effort being spent on processing all satellite data sources and authenticating access points to accomplish these works, the research team initially completed the harvesting schedule for northern Vietnam to determine the possible time of burning straw. They have further analyzed and mapped active fire zones to find areas where fires are caused by burning agricultural by-products. The team also analyzed active fire patterns concerning daily air quality measurements and combined weather data with satellite air pollution data to disperse air pollution and identify hot spots to map active fire patterns.

The design and implementation of this project have been accomplished through a collaborative effort with the Global Alliance on Health and Pollution (GAHP), the Vietnam Association for the Conservation of Nature and Environment (VACNE), and funded with UK aid from the UK Government.

GAHP was established in 2012, with more than 60 members from organizations and countries worldwide, aiming to reduce mortality and illness rates caused by large-scale environmental pollution in low and middle-income countries (LMIC).

VACNE was established 35 years ago and currently has 127 members,  with the main task of propagating, educating, raising awareness and knowledge of the local people, and mobilizing people to carry out environmental protection activities.

Meanwhile, UK Aid specializes in support for small and medium-sized civil society organizations (CSOs), working towards sustainable poverty reduction and implementing the UN's global goals.