Winter Study on Outdoor/Indoor Air Quality Measurements in Chitwan

Instruments set to collect data in the kitchen
photo: Subasana Shrestha/ICIMOD

A study of particulate matter (PM10) in ambient conditions was initiated in January 2016 by the Atmosphere Initiative of the International Centre for Integrated Mountain Development (ICIMOD) in Chitwan, Nepal. The study will help further the understanding contributions of indoor air pollution to outdoor pollution or the relation between indoor and outdoor air pollution.

Three villages - Ghokrella, Badreni and Gathauli (see map) in east, west and north, with reference to Chitwan National Park Air Quality Observatory - were chosen to obtain representative samples. The clusters were chosen away from roads in order to exclude suspended particles generated from vehicular movement. Air quality of indoor microenvironments was assessed from 15 January - 12 February 2016. Data from 30 households, 10 from each village were collected in the first phase of data collection in the winter this year. The second phase of the same will be conducted in summer at the same locality in Chitwan. While collecting data in the winter, the production of biogas was insufficient so the use of firewood increased. The need for firewood and other alternatives fuels peaked during winter. The second phase of the data collection during the summer will allow comparison between two data sets. In summer, biogas production will rise and the parameters of smoke can be identified and accessed. Seasonal effects of air pollution will be evident through this project.

The study’s objective is to establish a relationship between the indoor environment, the local surroundings of the villages, and the Air Quality Observatory measurements. Apart from measurements from the Chitwan National Park Air Quality Observatory, Ambient Monitoring of PM10 and indoor air quality measurements were considered for further inferences.

The team sets up e-samplers at the roof top to get data for the village
Photo: Subasana Shrestha/ICIMOD

With an attempt to understand air quality around the national park area and to check its impact on biodiversity and ecosystems, Chitwan National Park Air Quality Observatory was set in 26 December 2016. The setup was a joint collaboration between the Atmosphere Initiative and REDD Initiative of ICIMOD and National Trust for Nature Conservation (NTNC). The observatory was installed in the premises of NTNC Office in Chitwan.

During the first week, the concentrations of Black Carbon (BC) and Particulate Matter (PM) in the ambient air was considerably higher than WHO standards. Measurements revealed that the ambient 24-hour average PM10 was about 130 µg/m3, and PM2.5 was about 100 µg/m3 which was three folds higher than the WHO standard of 50 µg/m3 and 25 µg/m3 of PM10 and PM2.5 respectively. A 24-hr average ambient black carbon was about 8.8 µg/m3, shooting up to 180 µg/m3 during burning hours. Hence, an effort was made to identify the possible anthropogenic sources of BC and PM emissions.

Location map of the villages under study

E-samplers were placed on the roof of a village households for ambient PM10 monitoring. To monitor indoor air quality, 24-hour measurements from 30 households (10 houses per village) were taken. Instruments were placed in the kitchens and the bedrooms of each household and kept continuously running for two days to assess the actual exposure, totalling a sample size of 60. Kitchens were either attached or detached in the households under study. The portable instruments that were used indoors included MicroAeth, Aerosol Mass Monitor and IAQ Probe which projected measurements of black carbon; TSP, PM1, PM2.5, PM4 and PM10 and TVOC, CO, CO2, Temp. and RH. The three sets from indoor, cluster and baseline data retrieved from the Chitwan Air Quality Observatory will be assembled twice, before and after winter, and will be compared and analysed to find out the correlation and linkages later.

PM10 analyses shows that the Air Quality Observatory has a PM10 concentration of 130 µg/m3. Ghokrella, Badreni and Gathauli villages have PM10 concentrations of 472, 658 and 410 µg/m3 respectively, three times higher than the measurements recorded by the observatory.

Biomass was the chief fuel used in the kitchens followed by biogas and then by LPG. However, the use of biomass was dominant since production of biogas during winter is less or nominal and LPG was in short supply due to the blockade. It was perceived that the major sources of the pollutants were massive outdoor burning and indoor biomass burning for the purpose of heating and cooking, especially during winters. Preliminary results showed that the houses with attached kitchen and bedrooms posed larger risks to the inhabitants compared to the houses with detached set up. ICIMOD plans to make further gender based assessments on exposure studies. The team also plans to further investigate if the collected data have linkage to air pollution in Chitwan at large.

Different forms of outdoor burning prevalent in Chitwan
A team member of Atmosphere Initiative collects indoor data

For more information, please contact Subasana Shrestha and Alpha Thapa .