Dataset Information

DESIGN AND OPTIMIZATION OF A COMPACT LOW-COST OPTICAL PARTICLE SIZER.

ABSTRACT: Direct measurements of time- and size-resolved particulate matter (PM) concentrations are of major importance in air quality studies and pollution monitoring. Low-cost, compact optical particle counters (OPCs), which provide accurate PM measurements independent of the particle complex index of refraction (CRI), can be useful in personal exposure monitoring and distributed sensor network studies applications. A methodology is presented for the optimization of the sensor design and operation parameter space aimed at reducing the effect of the CRI on particle sizing errors. The Monte Carlo numerical simulation, which utilizes Mie scattering calculations, is used to determine the optimal detector angle for the specific set of constraints described by the weighting coefficients. The optimized detector position (? = 48°) has the lowest dependency on CRI over the entire particle size range of 0.5-10 microns. The near-forward, optimized, and perpendicular detector angles are compared experimentally using monodisperse 2 ?m and 4 ?m particles of silica, PSL, and alumina; the light collection cone angle is set at ? = 20° in all experiments. The data agree well with the numerical results for all tested scenarios. Overall, the perpendicular detector location has the best precision and worst accuracy related to the CRI variations. The optimized detector position has the best accuracy for both silica and alumina particles. The use of low-cost components, such as laser diodes, photodiodes, miniaturized integrated electronics, and simple component layouts allows for the development of compact OPCs capable of accurately sizing PM. The number of sizing bins, sizing accuracy and precision, and other parameters of interest can be used as an input to an optimization algorithm.

SUBMITTER: Njalsson T

PROVIDER: S-EPMC6159267 | biostudies-literature | 2018 May

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

DESIGN AND OPTIMIZATION OF A COMPACT LOW-COST OPTICAL PARTICLE SIZER.

Njalsson Tomas T Novosselov Igor I

Journal of aerosol science 20180110

Direct measurements of time- and size-resolved particulate matter (PM) concentrations are of major importance in air quality studies and pollution monitoring. Low-cost, compact optical particle counters (OPCs), which provide accurate PM measurements independent of the particle complex index of refraction (CRI), can be useful in personal exposure monitoring and distributed sensor network studies applications. A methodology is presented for the optimization of the sensor design and operation param ...[more]

PMID: 30270936

Similar Datasets

Project description:The aerosol scattering coefficient and Ångström exponent (AE) are important parameters in the understanding of aerosol optical properties and aerosol direct effect. These parameters are usually measured by a nephelometer network which is under-represented geographically; however, a rapid growth of air-pollution monitoring, using low-cost particle sensors, may extend observation networks. This paper presents the results of co-located measurements of aerosol optical properties, such as the aerosol scattering coefficient and the scattering AE, using low-cost sensors and using a scientific-grade polar Aurora 4000 nephelometer. A high Pearson correlation coefficient (0.94-0.96) between the low-cost particulate matter (PM) mass concentration and the aerosol scattering coefficient was found. For the PM10 mass concentration, the aerosol scattering coefficient relation is linear for the Dfrobot SEN0177 sensor and non-linear for the Alphasense OPC-N2 device. After regression analyses, both low-cost instruments provided the aerosol scattering coefficient with a similar mean square error difference (RMSE) of about 20 Mm-1, which corresponds to about 27% of the mean aerosol scattering coefficient. The relative uncertainty is independent of the pollution level. In addition, the ratio of aerosol number concentration between different bins showed a significant statistical (95% of confidence level) correlation with the scattering AE. For the SEN0177, the ratio of the particle number in bin 1 (radius of 0.15-0.25 µm) to bin 4 (radius of 1.25-2.5 µm) was a linear function of the scattering AE, with a Pearson correlation coefficient of 0.74. In the case of OPC-N2, the best correlation (r = 0.66) was found for the ratio between bin 1 (radius of 0.19-0.27 µm) and bin 2 (radius of 0.27-0.39 µm). Comparisons of an estimated scattering AE from a low-cost sensor with Aurora 4000 are given with the RMSE of 0.23-0.24, which corresponds to 16-19%. In addition, a three-year (2016-2019) observation by SEN0177 indicates that this sensor can be used to determine an annual cycle as well as a short-term variability.

Dataset Information

DESIGN AND OPTIMIZATION OF A COMPACT LOW-COST OPTICAL PARTICLE SIZER.

Publications

DESIGN AND OPTIMIZATION OF A COMPACT LOW-COST OPTICAL PARTICLE SIZER.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets