In:
Atmospheric Chemistry and Physics, Copernicus GmbH, Vol. 21, No. 9 ( 2021-05-11), p. 7199-7215
Abstract:
Abstract. The development of low-cost sensors and novel calibration
algorithms provides new hints to complement conventional ground-based
observation sites to evaluate the spatial and temporal distribution of
pollutants on hyperlocal scales (tens of meters). Here we use sensors
deployed on a taxi fleet to explore the air quality in the road network of
Nanjing over the course of a year (October 2019–September 2020). Based on GIS
technology, we develop a grid analysis method to obtain 50 m resolution maps
of major air pollutants (CO, NO2, and O3). Through hotspot
identification analysis, we find three main sources of air pollutants
including traffic, industrial emissions, and cooking fumes. We find that CO
and NO2 concentrations show a pattern: highways 〉 arterial
roads 〉 secondary roads 〉 branch roads 〉
residential streets, reflecting traffic volume. The O3
concentrations in these five road types are in opposite order due to the
titration effect of NOx. Combined the mobile measurements and the stationary
station data, we diagnose that the contribution of traffic-related
emissions to CO and NO2 are 42.6 % and 26.3 %, respectively.
Compared to the pre-COVID period, the concentrations of CO and NO2
during the COVID-lockdown period decreased for 44.9 % and 47.1 %,
respectively, and the contribution of traffic-related emissions to them both
decreased by more than 50 %. With the end of the COVID-lockdown period,
traffic emissions and air pollutant concentrations rebounded substantially,
indicating that traffic emissions have a crucial impact on the variation of
air pollutant levels in urban regions. This research demonstrates the sensing power of mobile monitoring for urban air pollution, which provides detailed
information for source attribution, accurate traceability, and potential
mitigation strategies at the urban micro-scale.
Type of Medium:
Online Resource
ISSN:
1680-7324
DOI:
10.5194/acp-21-7199-2021
DOI:
10.5194/acp-21-7199-2021-supplement
Language:
English
Publisher:
Copernicus GmbH
Publication Date:
2021
detail.hit.zdb_id:
2092549-9
detail.hit.zdb_id:
2069847-1
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