ONA {BlackCarbon}

Optimized Noise Reduction Averaging (ONA) algorithm

Description

The function uses the Optimized Noise Reduction Averaging (ONA) algorithm to process the raw black carbon data collected by Aethalometers (MicroAeth AE51, AethLabs, CA, USA).The algorithm smooths the black carbon concentration over a varying smoothing window identified by change in coefficient of light attenuation (ATN).

Usage

  ONA(data=data, ATN = "ATN", BC ="BC", dATN =0.05)

Arguments

data

it is a datafram generated by the AE51 device at the file level and not compiled with other files, however, a little pre-processing has to be done such as naming the columns and formatting it as a data frame.

ATN

the column having ATN coefficient.

BC

the column having raw black carbon data.

dATN

the difference in ATN coefficient which is used for defining the averaging window of raw black carbon concentration, by default it is 0.05.

Details

This method is only applicable when the raw files are not compiled

Value

The default method returns a vector with equal length as the dataframe

Note

Higly recommend to read the reference before using the function

Author(s)

Sanjeev Bista (MPH - Advanced Bio-statistics and Epidemiology)

References

Hagler GSW, Yelverton TLB, Vedantham R, Hansen ADA, Turner JR. Post-processing Method to Reduce Noise while Preserving High Time Resolution in Aethalometer Real-time Black Carbon Data. Aerosol Air Qual Res [Internet]. 2011 Oct [cited 2020 May 3];11(5):539–46. Available from: http://www.aaqr.org/doi/10.4209/aaqr.2011.05.0055

See Also

mean lapply

Examples

  data(data_ONA) # loading example dataset
  ONA(data=data_ONA, ATN = "ATN", BC ="BC", dATN =0.05)

  data(data_compiled) #loading the example dataset compiled at file level
  #applying ONA on a compiled file where data come from different files
  data_compiled$file_ID<-as.factor(data_compiled$file_ID)
  data_compiled$ONA_BC<-unlist(lapply(split(data_compiled, data_compiled$file_ID),
  function(x) ONA(data=x, ATN = "ATN", BC ="BC", dATN =0.05)))