Bias caused by water adsorption in hourly PM measurements

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

Beta-attenuation monitors are used worldwide to monitor PM mass concentration with high temporal resolution. Hourly PM10 and PM2. 5 dry mass concentrations are publicly available with the tacit assumption that water is effectively removed prior to the measurement. However, as both the filter material of the monitor and the aerosol particles are capable of retaining a significant amount of water even at low relative humidities, the basic assumption may not be valid, resulting in significant bias in reported PM10 and PM2. 5 concentrations. Here we show that in PM10 measurement, particle-free air can produce apparent hourly average PM concentrations in the range of g13-+21gμgg mg3 under conditions of fluctuating relative humidity. Positive and negative apparent readings are observed with increasing and decreasing relative humidities, respectively. Similar phenomena have been observed when the instrument filter was previously loaded with atmospheric aerosol. As a result the potential measurement biases in hourly readings arising from the interaction with water may be in the range of g53... + 69g%.

Original languageEnglish
Pages (from-to)2477-2484
Number of pages8
JournalAtmospheric Measurement Techniques
Volume10
Issue number7
DOIs
Publication statusPublished - Jul 13 2017

Fingerprint

relative humidity
adsorption
aerosol
filter
water
air
particle
material

ASJC Scopus subject areas

  • Atmospheric Science

Cite this

Bias caused by water adsorption in hourly PM measurements. / Kiss, G.; Imre, Kornelia; Molnár, A.; Gelencsér, A.

In: Atmospheric Measurement Techniques, Vol. 10, No. 7, 13.07.2017, p. 2477-2484.

Research output: Contribution to journalArticle

@article{7a3065ceb6a44057a3e3ae4909710868,
title = "Bias caused by water adsorption in hourly PM measurements",
abstract = "Beta-attenuation monitors are used worldwide to monitor PM mass concentration with high temporal resolution. Hourly PM10 and PM2. 5 dry mass concentrations are publicly available with the tacit assumption that water is effectively removed prior to the measurement. However, as both the filter material of the monitor and the aerosol particles are capable of retaining a significant amount of water even at low relative humidities, the basic assumption may not be valid, resulting in significant bias in reported PM10 and PM2. 5 concentrations. Here we show that in PM10 measurement, particle-free air can produce apparent hourly average PM concentrations in the range of g13-+21gμgg mg3 under conditions of fluctuating relative humidity. Positive and negative apparent readings are observed with increasing and decreasing relative humidities, respectively. Similar phenomena have been observed when the instrument filter was previously loaded with atmospheric aerosol. As a result the potential measurement biases in hourly readings arising from the interaction with water may be in the range of g53... + 69g{\%}.",
author = "G. Kiss and Kornelia Imre and A. Moln{\'a}r and A. Gelencs{\'e}r",
year = "2017",
month = "7",
day = "13",
doi = "10.5194/amt-10-2477-2017",
language = "English",
volume = "10",
pages = "2477--2484",
journal = "Atmospheric Measurement Techniques",
issn = "1867-1381",
publisher = "Copernicus Gesellschaft mbH",
number = "7",

}

TY - JOUR

T1 - Bias caused by water adsorption in hourly PM measurements

AU - Kiss, G.

AU - Imre, Kornelia

AU - Molnár, A.

AU - Gelencsér, A.

PY - 2017/7/13

Y1 - 2017/7/13

N2 - Beta-attenuation monitors are used worldwide to monitor PM mass concentration with high temporal resolution. Hourly PM10 and PM2. 5 dry mass concentrations are publicly available with the tacit assumption that water is effectively removed prior to the measurement. However, as both the filter material of the monitor and the aerosol particles are capable of retaining a significant amount of water even at low relative humidities, the basic assumption may not be valid, resulting in significant bias in reported PM10 and PM2. 5 concentrations. Here we show that in PM10 measurement, particle-free air can produce apparent hourly average PM concentrations in the range of g13-+21gμgg mg3 under conditions of fluctuating relative humidity. Positive and negative apparent readings are observed with increasing and decreasing relative humidities, respectively. Similar phenomena have been observed when the instrument filter was previously loaded with atmospheric aerosol. As a result the potential measurement biases in hourly readings arising from the interaction with water may be in the range of g53... + 69g%.

AB - Beta-attenuation monitors are used worldwide to monitor PM mass concentration with high temporal resolution. Hourly PM10 and PM2. 5 dry mass concentrations are publicly available with the tacit assumption that water is effectively removed prior to the measurement. However, as both the filter material of the monitor and the aerosol particles are capable of retaining a significant amount of water even at low relative humidities, the basic assumption may not be valid, resulting in significant bias in reported PM10 and PM2. 5 concentrations. Here we show that in PM10 measurement, particle-free air can produce apparent hourly average PM concentrations in the range of g13-+21gμgg mg3 under conditions of fluctuating relative humidity. Positive and negative apparent readings are observed with increasing and decreasing relative humidities, respectively. Similar phenomena have been observed when the instrument filter was previously loaded with atmospheric aerosol. As a result the potential measurement biases in hourly readings arising from the interaction with water may be in the range of g53... + 69g%.

UR - http://www.scopus.com/inward/record.url?scp=85024372229&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85024372229&partnerID=8YFLogxK

U2 - 10.5194/amt-10-2477-2017

DO - 10.5194/amt-10-2477-2017

M3 - Article

AN - SCOPUS:85024372229

VL - 10

SP - 2477

EP - 2484

JO - Atmospheric Measurement Techniques

JF - Atmospheric Measurement Techniques

SN - 1867-1381

IS - 7

ER -