Fireworks induced quasi-ultrafine particle number concentration and size-resolved elemental distribution in megacity Delhi

Abstract. Ambient particle number size distributions were measured in Paris, France during summer (1–31 July 2009) and winter (15 January–15 February 2010) at three fixed ground sites and using two mobile laboratories and one airplane. The campaigns were part of the MEGAPOLI project. New particle formation (NPF) was observed only during summer at approximately 50% of the campaign days, assisted by the low condensation sink (about 10.7 ± 5.9 × 10−3 s−1). NPF events inside the Paris plume were also observed at 600 m altitude onboard an aircraft simultaneously with regional events identified on the ground. Increased particle number concentrations were measured aloft also outside of the Paris plume at the same altitude, and were attributed to NPF. The Paris plume was identified, based on increased particle number and black carbon concentration, up to 200 km away from Paris center during summer. The number concentration of particles with diameter exceeding 2.5 nm measured on the surface at Paris center was on average 6.9 ± 8.7 × 104 and 12.1 ± 8.6 × 104 cm−3 during summer and winter, respectively, and was found to decrease exponentially with distance from Paris. However, further than 30 km from the city center, the particle number concentration at the surface was similar during both campaigns. During summer one suburban site in the NE was not significantly affected by Paris emissions due to higher background number concentrations, while the particle number concentration at the second suburban site in the SW increased by a factor of three when it was downwind of Paris.

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41. Conversion of Particle Number to Beryllium Particle Number Concentration

10.3320/1.2765949 ◽

2001 ◽

Cited By ~ 1

Author(s):

M. Berakis ◽

M. McCawley ◽

M. Kent

Keyword(s):

Particle Number ◽

Number Concentration ◽

Particle Number Concentration

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Impact on Ultrafine Particles Concentration and Turbulent Fluxes of SARS-CoV-2 Lockdown in a Suburban Area in Italy

Atmosphere ◽

10.3390/atmos12030407 ◽

2021 ◽

Vol 12 (3) ◽

pp. 407

Author(s):

Antonio Donateo ◽

Adelaide Dinoi ◽

Gianluca Pappaccogli

Keyword(s):

Ultrafine Particles ◽

Particle Number ◽

Ultrafine Particle ◽

Turbulent Fluxes ◽

Number Concentration ◽

Suburban Area ◽

Observation Site ◽

Meteorological Forcing ◽

Restrictive Measures ◽

Measurement Area

In order to slow the spread of SARS-CoV-2, governments have implemented several restrictive measures (lockdown, stay-in-place, and quarantine policies). These provisions have drastically changed the routines of residents, altering environmental conditions in the affected areas. In this context, our work analyzes the effects of the reduced emissions during the COVID-19 period on the ultrafine particles number concentration and their turbulent fluxes in a suburban area. COVID-19 restrictions did not significantly reduce anthropogenic related PM10 and PM2.5 levels, with an equal decrement of about 14%. The ultrafine particle number concentration during the lockdown period decreased by 64% in our measurement area, essentially due to the lower traffic activity. The effect of the restriction measures and the reduction of vehicles traffic was predominant in reducing concentration rather than meteorological forcing. During the lockdown in 2020, a decrease of 61% in ultrafine particle positive fluxes can be observed. At the same time, negative fluxes decreased by 59% and our observation site behaved, essentially, as a sink of ultrafine particles. Due to this behavior, we can conclude that the principal particle sources during the lockdown were far away from the measurement site.

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