Using long-term air monitoring of semi-volatile organic compounds to evaluate the uncertainty in polyurethane-disk passive sampler-derived air concentrations

Passive air sampling for semi-volatile organic chemicals

“…Holt et al used the long time series of concurrent air samples taken in Košetice in the Czech Republic to assess the agreement between a PUF-PAS deployed for one month and four one-day HiVol samples taken during the same time. 514 For most PCBs, OCPs and PAHs, concentrations obtained from the two sampling techniques were statistically signicantly different from each other, irrespective of whether the effective air volume V air was derived using site-specic or generic SRs and what assumptions were made concerning the relative SR of particle-bound substances. Correlations between concentrations obtained from passive and active sampling were oen poor and linear regressions hardly ever showed a slope close to 1.…”

“…not one that is specic to a particular deployment, it may in fact be more transparent to not report volumetric air concentrations: the time-normalised sequestered amount has less uncertainty than the calculated (15, 47, 80, 120, 160, 200, 240, 280, 320 m) concentration, because the latter inherits the uncertainty of the SR. Several early PAS studies had reported spatial results in amount per sampler or amount per sampler per time, 29,280,390,391,432,433,448,469 but only recently has there been a reemergence of support for not necessarily reporting volumetric air concentrations. [514][515][516][517] This approach is clearly advisable when using a PAS whose SR under a given set of circumstances is not well established or even unknown. A good example is the study attaching a PAS to a gull, where it was entirely possible to compare the exposure of different birds using time-normalised sequestered amounts.…”

“…492 One would think that this represents a mature eld, where the community of PAS developers and users has a solid understanding of the strengths, limitations and uncertainties of this sampling technique. However, it is only as a result of a number of comprehensive evaluation studies conducted during the past few years 254,262,514,552 that increased awareness and a better quantitative understanding of these limitations and uncertainties have emerged.…”

Comparability of long-term temporal trends of POPs from co-located active and passive air monitoring networks in Europe

“…Four broad sources of uncertainty may inuence the assessment of temporal trends from air monitoring, including those affecting: (1) sampling, such as weather conditions and seasonality, as well as the regularity and duration of sampling events; (2) the sampler itself, such as artifacts and breakthrough, or insufficient sorption capacity; (3) compound analysis, such as instrumentation and detection limits; and (4) the trend analysis, such as data censoring and outliers. 4,5,19 The overall uncertainty of monitoring is most easily reduced by smoothing the possible effects of these uncertainties by assessing a sufficiently long time series. Ideally, this requires tens of samples for each time series.…”

“…The comparability of active and passive sampling is confounded by uncertainties in sampling rates and particlephase dynamics (including sampling efficiency) which affect the derivation of air concentrations required for the interpretation of passive sampling data. [3][4][5][6] Differences in the sampling duration, volume and frequency between monitoring networks may also affect the comparability of active and passive sampling results (e.g. active sampling for 24 h once per week vs. continuous passive sampling for 84 d).…”