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Validation of diffusive samplers for nitrogen oxides and applications in various environments
Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine. (Arcum)
2014 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The overall aim of this thesis was to validate diffusive samplers for measurements of nitrogen dioxide (NO2) and nitrogen oxides (NOx). The Willems badge was validated for NO2 measurements both in laboratory tests and in field tests (Paper I-II). The sampling rate was 40.0 mL/min for ambient air concentrations and 46.0 mL/min for higher concentrations. No effects of different factors on sampling rate were found except for a reduced sampling rate at low wind velocity. The results of the laboratory validation were confirmed in field tests in ambient air and with personal sampling. The correlation between diffusive samplers and the reference monitor was good for ambient measurements. In conclusion, the Willems badge performs well at wind velocities down to 0.3 m/s, and this makes it suitable for personal sampling but less suitable for measurements in indoor air where the wind velocity is lower. Paper III reports about the field validation of the Ogawa diffusive samplers. Absolute humidity and temperature were found to have the strongest effect on sampling rate with lower uptake rates at low absolute humidity or temperature. The sampling rates above 0 °C were 8.6 mL/min for NO2 and 9.9 mL/min for NOx. NO2 and NOx concentrations that were determined using the manufacturer’s protocol were either underestimated or overestimated. The agreement between concentrations measured by the Ogawa sampler and the reference monitor was improved when field-determined sampling rates were used to calculate concentrations. Paper IV is based on a study with the aim of assessing the exposure of the Swedish general population to NO2 and some carcinogenic substances. The surveys were performed in one of five Swedish cities every year. In each survey, personal measurements of NO2 and some carcinogenic substances were conducted on 40 randomly selected individuals. In the study presented in this thesis, the NO2 part of the study is in focus and results were available for eight surveys conducted across the five cities. The estimated arithmetic mean concentration for the general Swedish population was 14.1 μg/m3. The exposure level for NO2 was higher for smokers compared with non-smokers, and the NO2 exposure levels were higher for people who had gas stoves at home or who were exposed at their workplace. The exposure was lower for those who had oil heating in their houses.

Place, publisher, year, edition, pages
Umeå: Umeå universitet , 2014. , 67 p.
Series
Umeå University medical dissertations, ISSN 0346-6612 ; 1685
Keyword [en]
Nitrogen dioxide, NOx, diffusive sampling, validation, vehicle exhaust, exposure measurement
National Category
Environmental Health and Occupational Health
Identifiers
URN: urn:nbn:se:umu:diva-95757ISBN: 978-91-7601-144-7 (print)OAI: oai:DiVA.org:umu-95757DiVA: diva2:760926
Public defence
2014-11-28, Hörsal B Unod T 9, Norrlands universitetssjukhus, Umeå, 09:00 (Swedish)
Opponent
Supervisors
Available from: 2014-11-07 Created: 2014-11-05 Last updated: 2017-02-14Bibliographically approved
List of papers
1. Validation of a diffusive sampler for NO2
Open this publication in new window or tab >>Validation of a diffusive sampler for NO2
1999 (English)In: Journal of Environmental Monitoring, ISSN 1464-0325, E-ISSN 1464-0333, Vol. 1, 349-352 p.Article in journal (Refereed) Published
Abstract [en]

A diffusive sampler for NO2, Willems badge, was validated in laboratory experiments and field tests. The collecting reagent for NO2 in the sampler is triethanolamine, and the analysis is based on a modified colorimetric method, the

Saltzman method. The analysis was performed by a flow injection analysis (FIA) technique. The sampling rate for the sampler was determined to be 40.0 ml min−1. There was no effect of NO2 concentration or relative humidity on sampling rate, and the influence of sampling time was found to be small. The detection limit was 4 mg m−3 for a 24 h

sample. The capacity is high enough to allow sampling of 150 mg m−3 for 7 days, which is twice the recommended Swedish short-term (24 h) guideline value as a 98-percentile over 6 months. In field tests, the sampler performedwell, even at wind speeds higher than 2 m s−1, and at low temperatures. The overall uncertainty of the method was 24%. The sensitivity and capacity of the method also make it suitable for personal sampling for 2–8 h in working environments.

Place, publisher, year, edition, pages
Royal Society of Chemistry, 1999
Keyword
diffusive sampler, NO2, validation
National Category
Environmental Health and Occupational Health Chemical Sciences
Research subject
Analytical Chemistry
Identifiers
urn:nbn:se:umu:diva-95729 (URN)10.1039/A902937K (DOI)000083696300017 ()
Conference
AIRMON, 1999, Geilo, Norway
Available from: 2014-11-05 Created: 2014-11-04 Last updated: 2017-12-05Bibliographically approved
2. Validation of the Willems badge diffusive sampler for nitrogen dioxide determinations in occupational environments
Open this publication in new window or tab >>Validation of the Willems badge diffusive sampler for nitrogen dioxide determinations in occupational environments
2002 (English)In: The Analyst, ISSN 0003-2654, E-ISSN 1364-5528, Vol. 127, no 1, 163-168 p.Article in journal (Refereed) Published
Abstract [en]

The Willems badge, a diffusive sampler for nitrogen dioxide, has previously been validated for ambient air measurements. This paper describes the laboratory and field validation of the Willems badge for personal sampling under working environment conditions. The mean sampling rate in the laboratory tests was 46 ml min(-1), with an RSD of 12%. No statistically significant effects on sampling rate of the sampling time, concentration of NO2 or relative humidity were found. A slightly decreased sampling rate was observed at low wind velocity. This was also confirmed during static sampling, which makes the sampler less appropriate for static sampling indoors. No back diffusion was observed. Storage of the samplers for two weeks before or after exposure did not affect the sampling rate. Our analysis is based on a modified colorimetric method, performed by FIA (flow injection analysis). This technique was compared to ion chromatography analysis. The use of ion chromatography lowered the detection limit from 11 to 2 microg m(-3) for an 8 h sample, and furthermore enabled the detection of other anions. In conclusion, the diffusive sampler was found to perform well for personal measurements in industrial environments.

Place, publisher, year, edition, pages
Royal Society of Chemistry, 2002
National Category
Chemical Sciences Environmental Health and Occupational Health
Identifiers
urn:nbn:se:umu:diva-83469 (URN)10.1039/b107844e (DOI)000173475200033 ()11827385 (PubMedID)
Available from: 2013-11-26 Created: 2013-11-26 Last updated: 2017-12-06Bibliographically approved
3. Field validation of the Ogawa diffusive sampler for NO(2) and NO(x) in a cold climate
Open this publication in new window or tab >>Field validation of the Ogawa diffusive sampler for NO(2) and NO(x) in a cold climate
2010 (English)In: Journal of Environmental Monitoring, ISSN 1464-0325, E-ISSN 1464-0333, Vol. 12, no 6, 1315-24 p.Article in journal (Refereed) Published
Abstract [en]

A small-scale field trial in Umeå, Sweden with Ogawa samplers and a chemiluminescence instrument indicated that the NO(2) concentration was underestimated with respect to the reference monitor, if calculated according to the manufacturer's Ogawa sampling protocol. By co-locating Ogawa samplers and reference monitors at six sites in two Swedish cities, uptake rates were determined for NO(2) and NO(x) better applicable to the Swedish conditions and climate. The concentrations of NO(2) and NO(x) calculated according to the instruction manual of the sampler and using the field-determined uptake rates were compared with values derived from chemiluminescence monitors for each week over which samples were taken. When calculated according to the manufacturer's suggested protocol, the Ogawa sampler underestimated the NO(2) concentrations by 9.1% on average for all samples (N = 53), with respect to the reference monitor. In contrast, NO(x) concentrations were overestimated by a mean value of 15% for all samples (N = 45). By using the field determined uptake rates for the calculation of NO(2) and NO(x) a better estimation of the concentrations was obtained. The ratio between concentrations determined with the Ogawa samplers and chemiluminescence monitors was then 1.02 for all measurements of NO(2) and 1.00 for NO(x). Precision, expressed as the mean coefficient of variation, was 6.4% for six, 6-replicate measurements of NO(2) and 3.7% for five, 6-replicate measurements of NO(x).

Place, publisher, year, edition, pages
Royal Society of Chemistry, 2010
National Category
Environmental Health and Occupational Health
Identifiers
urn:nbn:se:umu:diva-34783 (URN)10.1039/b924615k (DOI)000278588400012 ()20532384 (PubMedID)
Available from: 2010-06-18 Created: 2010-06-18 Last updated: 2017-12-12Bibliographically approved
4. Determinants of personal exposure to some carcinogenic substances and nitrogen dioxide among the general population in five Swedish cities
Open this publication in new window or tab >>Determinants of personal exposure to some carcinogenic substances and nitrogen dioxide among the general population in five Swedish cities
Show others...
2014 (English)In: Journal of Exposure Science and Environmental Epidemiology, ISSN 1559-0631, E-ISSN 1559-064X, Vol. 24, no 4, 437-443 p.Article in journal (Refereed) Published
Abstract [en]

Environmental levels of airborne carcinogenic and related substances are comparatively better known than individual exposure and its determinants. We report on a personal monitoring program involving five Swedish urban populations. The aim of the program was to investigate personal exposure to benzene, 1,3-butadiene, formaldehyde, and nitrogen dioxide (NO2). The measurements were performed among 40 inhabitants during seven consecutive days, in one urban area each year, during 2000-2008. The estimated population exposure levels were 1.95 μg/m(3) for benzene, 0.56 μg/m(3) for 1,3-butadiene, 19.4 μg/m(3) for formaldehyde, and 14.1 μg/m(3) for NO2. Statistical analysis using a mixed-effects model revealed that time spent in traffic and time outdoors contributed to benzene and 1,3- butadiene exposure. For benzene, refueling a car was an additional determinant influencing the exposure level. Smoking or environmental tobacco smoke were significant determinants of exposure to NO2, benzene, and 1,3-butadiene. Those with a gas stove had higher NO2 exposure. Living in a single-family house increased the exposure to formaldehyde significantly. In a variance component model, the between-subject variance dominated for 1,3-butadiene and formaldehyde, whereas the between-city variance dominated for NO2. For benzene, the between-subject and between-cities variances were similar.

Place, publisher, year, edition, pages
Nature Publishing Group, 2014
Keyword
personal exposure, benzene, 1.3-butadiene, nitrogen dioxide, formaldehyde, mixed models
National Category
Environmental Health and Occupational Health
Identifiers
urn:nbn:se:umu:diva-80994 (URN)10.1038/jes.2013.57 (DOI)000337651800013 ()24064531 (PubMedID)
Available from: 2013-09-30 Created: 2013-09-30 Last updated: 2017-12-06Bibliographically approved

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