Ambient air quality of Kathmandu valley as reflected by atmospheric particulate matter concentrations (PM10)

Giri, Dhiraj; Murthy, K. V.; Adhikary, P. R.; Khanal, Sanjay Nath

doi:10.1007/bf03325949

Cited by 49 publications

(39 citation statements)

References 10 publications

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“…Approximately 10 highly polluting brick kilns are located within a 2-km radius of the site, and are in operation from January to April every year. The wind direction through the valley is usually southwesterly or westerly, with relatively low speeds in the range of 0.5-7.5 m/s (Giri et al, 2006;Shrestha and Aryal, 2011). Therefore, the site receives urban air pollution from three major cities in the valley, namely Kathmandu, Lalitpur, and Bhaktapur, located to the west, southwest, and southeast of the site, respectively.…”

Section: Sampling and Analysismentioning

confidence: 99%

“…South Asian monsoon circulations influence the weather in Nepal, which is characterized by four distinct seasons: winter (December-February), pre-monsoon (MarchMay), monsoon (June-September), and post-monsoon (October-November) seasons (Bonasoni et al, 2010). The summer monsoon season is hot, humid, and rainy, with nearly 80% of the annual precipitation of 1400 mm occurring in 4 months (Giri et al, 2006). The post-monsoon season is warm and sunny.…”

Section: Sampling and Analysismentioning

confidence: 99%

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Characteristics and sources of polycyclic aromatic hydrocarbons in atmospheric aerosols in the Kathmandu Valley, Nepal

Chen

Kang

et al. 2015

Science of The Total Environment

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• High concentrations of 4-6 ring PAHs were reported in the atmosphere of Kathmandu.• PAH concentrations in non-monsoon season were higher than those in monsoon season.• PAH ratios indicated that diesel and biomass fuels were main emission sources.• Toxic equivalent concentration of PAHs was 26 times higher than the WHO guideline. The Kathmandu Valley in the foothills of the Himalayas, where the capital city of Nepal is located, has one of the most serious air pollution problems in the world. In this study, total suspended particle (TSP) samples collected over a year (April 2013-March 2014 in the Kathmandu Valley were analyzed for determining the concentrations of 15 priority particle-bound polycyclic aromatic hydrocarbons (PAHs). The TSP and PAH concentrations were extremely high, with annual average concentration being 199 ± 124 μg/m 3 and 155 ± 130 ng/m 3 , respectively, which are comparable to those observed in Asian cities such as Beijing and Delhi. The TSP and PAH concentrations varied considerably, with the seasonal average concentration being maximal during the post-monsoon season followed by, in descending order, the winter, pre-monsoon, and monsoon seasons. In the winter and premonsoon seasons, ambient TSP and PAH concentrations increased because of emissions from brick kilns and the use of numerous small generators. Moreover, in the pre-monsoon season, forest fires in the surrounding regions influenced the TSP and PAH concentrations in the valley. PAHs with 4 to 6 rings constituted a predominant proportion (92.3-93.3%) of the total PAHs throughout the year. Evaluation of diagnostic molecular ratios indicated that the atmospheric PAHs in the Kathmandu Valley originated mainly from diesel and biomass G R A P H I C A L A B S T R A C T a b s t r a c t a r t i c l e i n f o Contents lists available at ScienceDirectScience of the Total Environment j o u r n a l h o m e p a g e : w w w . e l s e v i e r . c o m / l o c a t e / s c i t o t e n v combustion. The toxic equivalent quantity (TEQ) of particle phase PAHs ranged between 2.74 and 81.5 ng TEQ/ m 3 , which is considerably higher than those reported in other South Asian cities, and 2-80 times higher than the World Health Organization guideline (1 ng TEQ/m 3 ). This suggests that ambient PAH levels in the Kathmandu Valley pose a serious health risk to its approximately 3.5 million residents.

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Section: Sampling and Analysismentioning

confidence: 99%

Section: Sampling and Analysismentioning

confidence: 99%

Characteristics and sources of polycyclic aromatic hydrocarbons in atmospheric aerosols in the Kathmandu Valley, Nepal

Chen

Kang

et al. 2015

Science of The Total Environment

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“…Due to the different source strengths, aerosol burdens, and the composition of aerosol and ground surfaces, HONO chemistry in South Asia is expected to have different features from what has been found in Europe or North America. For example, the average atmospheric aerosol burden in Kathmandu in winter is much higher than in European and US cities (Sharma et al, 2002;Sharma, 1997;Yu et al, 2008a;Giri et al, 2006). Moreover, strong nocturnal inversion layer (Kondo et al, 2002;Regmi et al, 2003;Panday, 2006;Panday and Prinn, 2009) and the A home-made long-path DOAS (Chalmers University) was used to measure HONO and NO 2 in Kathmandu with a time resolution of around 5-10 min.…”

Section: Introductionmentioning

confidence: 99%

Observations of high rates of NO<sub>2</sub>-HONO conversion in the nocturnal atmospheric boundary layer in Kathmandu, Nepal

Galle

Panday

et al. 2009

Atmos. Chem. Phys.

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Abstract. Nitrous acid (HONO) plays a significant role in the atmosphere, especially in the polluted troposphere. Its photolysis after sunrise is an important source of hydroxyl free radicals (OH). Measurements of nitrous acid and other pollutants were carried out in the Kathmandu urban atmosphere during January-February 2003, contributing to the sparse knowledge of nitrous acid in South Asia. The results showed average nocturnal levels of HONO (1.7±0.8 ppbv), NO 2 (17.9±10.2 ppbv), and PM 10 (0.18±0.11 mg m −3 ) in urban air in Kathmandu. Surprisingly high ratios of chemically formed secondary [HONO] to [NO 2 ] (up to 30%) were found, which indicates unexpectedly efficient chemical conversion of NO 2 to HONO in Kathmandu. The ratios of [HONO]/[NO 2 ] at night were found to be much higher than previously reported values from measurements in urban air in Europe, North America and Asia. The influences of aerosol surface, ground reactive surface, and relative humidity on NO 2 -HONO chemical conversion were discussed. The high humidity, strong and low inversion layer at night, and high aerosol pollution burden in Kathmandu may explain the particularly efficient conversion of NO 2 to HONO.

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“…Among the suspended particles in ambient air, atmospheric particulate matter with an aerodynamic diameter less than 10 µm (PM10), and especially the fine particle fraction with aerodynamic diameter less than 2.5 µm (PM2.5) are of considerable concern. The chemical composition of PM10 and PM2.5 is critically important to gain insights into sources and their atmospheric formation pathways and of their toxicity and to evaluate the effectiveness of abatement strategies for relevant emission sectors Tippayawong, et al, 2006;Giri, et al, 2006).…”

Section: Introductionmentioning

confidence: 99%

Seasonal Variation of Atmospheric Composition of Water-Soluble Inorganic Species at Rural Background Site in Tanzania, East Africa

Mkoma¹,

Wang²,

Maenhaut³

et al. 2010

Ethiop. J. Env Stud & Manag

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Ambient air quality of Kathmandu valley as reflected by atmospheric particulate matter concentrations (PM10)

Cited by 49 publications

References 10 publications

Characteristics and sources of polycyclic aromatic hydrocarbons in atmospheric aerosols in the Kathmandu Valley, Nepal

Characteristics and sources of polycyclic aromatic hydrocarbons in atmospheric aerosols in the Kathmandu Valley, Nepal

Observations of high rates of NO<sub>2</sub>-HONO conversion in the nocturnal atmospheric boundary layer in Kathmandu, Nepal

Seasonal Variation of Atmospheric Composition of Water-Soluble Inorganic Species at Rural Background Site in Tanzania, East Africa

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Ambient air quality of Kathmandu valley as reflected by atmospheric particulate matter concentrations (PM10)

Cited by 49 publications

References 10 publications

Characteristics and sources of polycyclic aromatic hydrocarbons in atmospheric aerosols in the Kathmandu Valley, Nepal

Characteristics and sources of polycyclic aromatic hydrocarbons in atmospheric aerosols in the Kathmandu Valley, Nepal

Observations of high rates of NO&lt;sub&gt;2&lt;/sub&gt;-HONO conversion in the nocturnal atmospheric boundary layer in Kathmandu, Nepal

Seasonal Variation of Atmospheric Composition of Water-Soluble Inorganic Species at Rural Background Site in Tanzania, East Africa

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Observations of high rates of NO<sub>2</sub>-HONO conversion in the nocturnal atmospheric boundary layer in Kathmandu, Nepal