Pulsed differential optical absorption spectroscopy applied to air pollution measurement in urban troposphere

Simultaneous Monitoring of Nitrogen Dioxide and Aerosol Concentrations with Dual Path Differential Optical Absorption Spectroscopy

“…The method of pulsed DOAS [6]- [8] [13] was employed for the present measurement. As shown in Figure 2, xenon flash lamps (Sanken Electric, FX-7, Japan) mounted on an electric power tower or a smoke stack were exploited as DOAS light sources, providing flash events every 1.5 s during the daytime.…”

Multi-Wavelength and Multi-Direction Remote Sensing of Atmospheric Aerosols and Clouds

“…The method of differential optical absorption spectroscopy (DOAS) provides a useful tool for monitoring atmospheric pollutants through the measurement of optical extinction (i.e., the sum of absorption and scattering) over a light path length of a few kilometres (Yoshii et al, 2003, Lee et al, 2009Si et al, 2005;Kuriyama et al, 2011 visible spectral region is quite suitable for urban air pollution studies, since both nitrogen dioxide (NO 2 ) and aerosol, the most important pollutants originated from human activities, can directly be measured using a near horizontal light path in the lower troposphere.…”

“…Although conventional approach in the DOAS measurement is to install a light source, our group at the Centre for Environmental Remote Sensing (CEReS), Chiba University, has established a unique DOAS approach based on aviation obstruction lights (white flashlights) equipped at tall constructions such as smokestacks (Yoshii et al, 2003, Si et al, 2005Kuriyama et al, 2011). Since those xenon lamps produce flash pulses every 1.5 s during the daytime, they can easily be recognized with the coverage of the whole visible spectral range.…”

Urban air pollution monitoring using differential optical absorption spectroscopy (DOAS) and wind lidar

“…For retrieving aerosol optical thickness, on the other hand, three wavelengths of 355, 532, and 756 nm are employed with the assumption that the aerosol optical thickness can be expressed in a form of B -A , where B is called the turbidity constant and A the Angstrom exponent. The stable intensity of the light source (better than 2%) and the robustness of the detector setup enable the retrieval of aerosol optical thickness from the overall intensity of the DOAS data [2][3][4]. This is due to the fact that most of the intensity change arises from the variation of aerosol loading in the regulation, it is required for constructions taller than 60 m to have conspicuous signs for avoiding aviation obstruction.…”

“…Although ground-based sampling stations can provide data on air pollutants, such point sampled data do not always represent data in a wider region. The technique of differential optical absorption spectroscopy (DOAS) enables the monitoring atmospheric environment along the optical path of several hundred meters to several kilometers [1][2][3][4]. Besides, by utilizing proper range in the visible wavelength, the DOAS technique makes it possible to simultaneously measure the concentrations of nitric dioxide (NO 2 ) and aerosol, two important species in urban environmental pollution.…”