A multi-channel integrating nephelometer to measure real-time atmospheric aerosol scattering coefficients

Abstract. The aerosol extinction-to-backscatter ratio is an important parameter for inverting LIDAR signals in the LIDAR equation. It is a complicated function of the aerosol microphysical characteristics. In this paper, a method to retrieve the column-averaged aerosol extinction-to-backscatter ratio by constraining the aerosol optical depths (AOD) from a Micro-pulse LIDAR (MPL) by the AOD measurements from the Moderate Resolution Imaging Spectroradiometer (MODIS) is presented. Both measurements were taken on cloud free days between 1 May 2003 and 30 June 2004 over Hong Kong, a coastal city in south China. Simultaneous measurements of aerosol scattering coefficients with a forward scattering visibility sensor are compared with the LIDAR retrieval of aerosol extinction coefficients. The data are then analyzed to determine seasonal trends of the aetrosol extinction-to-backscatter ratio. In addition, the relationships between the extinction-to-backscatter ratio and wind conditions as well as other aerosol microphysical parameters are presented. The mean aerosol extinction-to-backscatter ratio for the whole period was found to be 29.1±5.8 sr, with a minimum of 18 sr in July 2003 and a maximum of 44 sr in March 2004. The ratio is lower in summer because of the dominance of oceanic aerosols in association with the prevailing southwesterly monsoon. In contrast, relatively larger ratios are noted in spring and winter because of the increased impact of local and regional industrial pollutants associated with the northerly monsoon. The extended LIDAR measurements over Hong Kong provide not only a more accurate retrieval of aerosol extinction coefficient profiles, but also significant substantial information for air pollution and climate studies in the region.

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Radiative Impact of Fireworks at a Tropical Indian Location: A Case Study

Advances in Meteorology ◽

10.1155/2014/197072 ◽

2014 ◽

Vol 2014 ◽

pp. 1-8 ◽

Cited By ~ 7

Author(s):

B. P. Singh ◽

A. K. Srivastava ◽

S. Tiwari ◽

S. Singh ◽

R. K. Singh ◽

...

Keyword(s):

Behavioral Change ◽

Radiative Forcing ◽

Gangetic Plain ◽

Scattering Coefficients ◽

Aerosol Absorption ◽

Aerosol Scattering ◽

Radiative Impact ◽

Diwali Festival ◽

Indo Gangetic Plain

During Diwali festival, extensive burning of crackers and fireworks is made. Weeklong intensive observational campaign for aerosol study was carried out at a representative urban location in the eastern Indo-Gangetic Plain (IGP), Varanasi (25.3°N, 83.0°E), from October 29 to November 04, 2005 (Diwali on November 01, 2005), to investigate behavioral change of aerosol properties and radiative forcing between firework affected and nonaffected periods. Results show a substantial increase (~27%) in aerosol optical depth, aerosol absorption coefficients, and aerosol scattering coefficients during affected period as compared to non-affected periods. Magnitudes of radiative forcing at top of atmosphere during affected and non-affected periods are found to be +10 ± 1 and +12 ± 1 Wm−2, respectively, which are −31 ± 7 and −17 ± 5 Wm−2, respectively, at surface. It suggests an additional cooling of ~20% at top of atmosphere, ~45% cooling at surface, and additional atmospheric heating of 0.23 Kday−1during fireworks affected period, which is ~30% higher than the non-affected period average.

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Real-Time Monitoring of Atmospheric Aerosol at New Haven, CT, for Fluorescence Spectra, Particle Size and Concentration

Conference on Lasers and Electro-Optics/Quantum Electronics and Laser Science Conference and Photonic Applications Systems Technologies ◽

10.1364/phast.2007.ptue3 ◽

2007 ◽

Author(s):

Yong-Le Pan ◽

Richard K. Chang ◽

Ronald G. Pinnick ◽

Steven C. Hill

Keyword(s):

Particle Size ◽

Real Time ◽

Atmospheric Aerosol ◽

Fluorescence Spectra ◽

New Haven ◽

Real Time Monitoring

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The behaviour of the atmospheric aerosol scattering coefficient under varying meteorological conditions

Journal of Aerosol Science ◽

10.1016/0021-8502(86)90092-3 ◽

1986 ◽

Vol 17 (3) ◽

pp. 303

Author(s):

R. Hitzenberger

Keyword(s):

Atmospheric Aerosol ◽

Meteorological Conditions ◽

Scattering Coefficient ◽

Aerosol Scattering

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Application of time-of-flight aerosol mass spectrometry for the real-time measurement of particle-phase organic peroxides: an online redox derivatization–aerosol mass spectrometer (ORD-AMS)

Atmospheric Measurement Techniques ◽

10.5194/amt-13-5725-2020 ◽

2020 ◽

Vol 13 (10) ◽

pp. 5725-5738

Author(s):

Marcel Weloe ◽

Thorsten Hoffmann

Keyword(s):

Real Time ◽

Mass Spectrometer ◽

Atmospheric Aerosol ◽

Condensation Reaction ◽

High Mass ◽

Organic Peroxides ◽

Particle Phase ◽

Aerosol Mass Spectrometer ◽

Aerosol Mass ◽

Health Related

Abstract. Aerosol mass spectrometers (AMS) are frequently applied in atmospheric aerosol research in connection with climate, environmental or health-related projects. This is also true for the measurement of the organic fraction of particulate matter, still the least understood group of components contributing to atmospheric aerosols. While quantification of the organic and/or inorganic aerosol fractions is feasible, more detailed information about individual organic compounds or compound classes can usually not be provided by AMS measurements. In this study, we present a new method to detect organic peroxides in the particle phase in real-time using an AMS. Peroxides (ROOR') are of high interest to the atmospheric aerosol community due to their potentially high mass contribution to SOA, their important role in new particle formation and their function as “reactive oxygen species” in aerosol–health-related topics. To do so, supersaturated gaseous triphenylphosphine (TPP) was continuously mixed with the aerosol flow of interest in a condensation/reaction volume in front of the AMS inlet. The formed triphenylphosphine oxide (TPPO) from the peroxide–TPP reaction was then detected by an aerosol mass spectrometer (AMS), enabling the semiquantitative determination of peroxide with a time resolution of 2 min. The method was tested with freshly formed and aged biogenic VOC and ozone SOA as well as in a short proof-of-principle study with ambient aerosol.

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