Long-term (2005–2012) measurements of near-surface air pollutants at an urban location in the Indo-Gangetic Basin

Abstract

Simultaneous long-term measurements of near-surface air pollutants at an urban station, New Delhi, were studied during 2005-2012 to understand their distribution on different temporal scales. The annual mean mass concentrations of nitrogen dioxide (NO 2), sulphur dioxide (SO 2), particulate matter less than 10 µm (PM 10) and suspended particulate matter (SPM) were found to be 62.0 ± 27.6, 12.5 ± 8.2, 253.7 ± 134 and 529.2 ± 213.1 µg/m 3 , respectively. The 24-hr mean mass concentrations of NO 2 , PM 10 and SPM were exceeded on ∼27%, 87% and 99% days that of total available measurement days to their respective National Ambient Air Quality Standard (NAAQS) level. However, it never exceeded for SO 2 , which could be attributed to reduction of sulphur in diesel, use of cleaner fuels such as compressed natural gas, LPG, etc. The mean mass concentrations of measured air pollutants were found to be the highest during the winter/post-monsoon seasons, which are of concern for both climate and human health. The annual mean mass concentrations of NO 2 , PM 10 and SPM showed an increasing trend while SO 2 appears to be decreasing since 2008. Air mass cluster analysis showed that north-northwest trajectories accounted for the highest mass concentrations of air pollutants (more prominent in the winter/post-monsoon season); however, the lowest were associated with the southeast trajectory cluster.

Improved air quality during COVID-19 at an urban megacity over the Indo-Gangetic Basin: From stringent to relaxed lockdown phases

“…Data pertaining to air pollutants was obtained from the Delhi Pollution Control Committee (DPCC) at the residential site, Ashok Vihar in Delhi. A population density map of Delhi is shown recently by Kishore et al (2019) using 2011 Census data. As per the map, the present measurement site is situated in a densely populated locality in the North-West direction of Delhi, which is well connected through roads and public transport.…”

“…O 3 was measured using chemiluminescence method. More details of the measurements of these air pollutants along with their detection range and uncertainties are discussed by Kishore et al (2019) .…”

“…The city has been listed as one of the top-most polluted cities in the world ( WHO, 2016 ; Khanna and Sharma, 2020 ). The major anthropogenic activities in Delhi include vehicular exhaust, industrial emissions, residential pollution, and solid waste/biomass burning, which results in severe-to-worst air quality in the post-monsoon and early winter seasons ( Sahu et al, 2015 ; Kishore et al, 2019 ; Bikkina et al, 2019 ; Kanawade et al, 2020 ; Kulkarni et al, 2020 ; Tobler et al, 2020 ). The PM 2.5 concentrations in Delhi were generally found to exceed many folds to its national ambient air quality standards (NAAQS), given by the central pollution control board (CPCB) in the year 2009 ( https://cpcb.nic.in/uploads/National_Ambient_Air_Quality_Standards.pdf ).…”

Spatial distribution and temporal variation of atmospheric pollution in the South Gobi Desert, China, during 2016–2019

“…At that PM 2.5 and PM 10 concentrations demonstrate the similar tendencies in their formation. As PM 10 increases, PM 2.5 also increases (Kishore et al 2019); thus, on 15 May 2019 the whole territory of the South Gobi experienced a dust storm of various intensity with maximum concentrations in Wuwei (PM 10 1582 μg/m 3 PM 2.5 468 μg/m 3 ), Zhangye (PM 10 1040 μg/m 3 and PM 2.5 356 μg/m 3 ), and Zhongwei (PM 10 729 μg/m 3 and PM 2.5 232 μg/m 3 ), suggesting similar sources of aerosols formation. However, the dust event did not influence the change in NO 2 , SO 2 , and CO, which were 14, 9, and 12 μg/m 3 (for NO 2 ); 4, 4, and 8 μg/m 3 (for SO 2 ); 0.2, 0.2, and 0.4 mg/m 3 (for CO) for Wuwei, Zhangye, and Zhongwei, respectively.…”

“…Thus, in winter, Alashan is subject to the influence of emissions from fossil fuel burning (coal for heating) to an even greater degree than other cities, leading to high PM 2.5 /PM 10 ratio (December 0.58, January 0.61, February 0.56, with average seasonal value 0.58). The higher PM 2.5 /PM 10 ratios may also be attributed to vehicles emissions and secondary particles, formed through photochemical processes at high temperatures (Kishore et al 2019), while lower ratios in most scenarios are associated with violent sand and dust emissions from nearby deserts (Zhang 2016). Upon analysis of PM 2.5 /PM 10 ratio results obtained, it may be concluded that the main pollutant of all the cities of the region is coarse particles.…”