Face mask as an indicator and shield of human exposure to traditional and novel organophosphate esters.

Herein, the trapping effectiveness of N95, filter KN95, medical surgical masks (MSMs), and disposable medical masks (DMMs) against 19 airborne traditional and novel organophosphate esters (OPEs) was evaluated. Laboratory simulations (n = 24 for each type of mask) showed that time-dependent accumulation of ∑19OPEs on the four types of masks ranged between 30.1 and 86.6 ng in 24 h, with the highest and lowest median amounts trapped by the N95 masks (53.3 ng) and DMMs (43.2 ng), respectively. The trapping efficiency of the four types of masks for ∑19OPEs decreased over time from 84 % to 39 % in 24 h, with N95 masks showing the highest median efficiency (70 %). Further, field investigations were conducted in five types of microenvironments (train, hospital, bus, supermarket, and canteen), and an analysis of 200 samples showed that ∑19OPEs were accumulated in the masks with a variable amount from 3.7 to 117 ng/mask. Consistent with the laboratory simulations, the N95 masks (29.0 ng/mask) exhibited the highest hourly median amount of trapped OPEs, followed by the KN95 masks (24.5 ng/mask), MSMSs (17.4 ng/mask), and DMMs (15.8 ng/mask). Triethyl phosphate (TEP), tris(1-chloro-2-propyl) phosphate (TCIPP), tri-n-butyl phosphate (TNBP), and cresyl diphenyl phosphate (CDP) as well as 4-isopropylphenyl diphenyl phosphate (4IPPDPP) and 2,4-diisopropylphenyl diphenyl phosphate (24DIPPDPP) were the most commonly detected traditional and novel OPEs. Based on the amount of OPEs trapped on the masks, we estimated the concentration of ∑19OPEs in the train microenvironment to be the highest (222 ng/m3), which is approximately 2-5 times higher than that in the other microenvironments. The results of this study prove that masks can effectively protect humans from exposure to OPEs and act as low-cost indicators of indoor contamination.

Distribution of flame retardants among indoor dust, airborne particles and vapour phase from Beijing: spatial-temporal variation and human exposure characteristics.

The occurrence and distribution of 10 brominated flame retardants (BFRs) and 10 organophosphate flame retardants (OPFRs) were investigated in indoor dust, total suspended particles (TSP), and vapour phase from offices (n = 10), homes (n = 9), and day-care centres (n = 10) in Beijing, China. Three types of samples were collected biweekly from one office and one home over a year to examine temporal trends. BFRs in dust significantly correlated with those in TSP, while OPFRs significantly correlated among all three matrices. In addition, BFRs in dust (ng/g) and TSP (pg/m3) exhibited similar temporal trends with higher levels in the cold season, whereas OPFRs in TSP and vapour phase (pg/m3) showed similar temporal trends with higher levels in the warm season. The geometric mean concentrations of BFRs and OPFRs in the three matrices from the above mentioned three types of indoor microenvironments were used for exposure and health risk estimation, and ∑7OPFRs showed much higher hazard index (HI) values than ∑10BFRs for all subpopulations, and inhalation of OPFRs was a major risk source. With the volatility of flame retardants (FRs) decreasing, the contribution of dust ingestion and dermal absorption showed an increasing trend, and the contribution of inhalation exhibited a gradual decreasing trend, which implied the dominant exposure pathway to FRs is strongly related to the vapour pressure (25 °C, Pa) of these substances. Using a single type of microenvironment or the collection of samples at a single point in time can lead to overestimation or underestimation of overall exposure and risk for people to some extent. The correlations of FRs in dust, TSP, and vapour phase from indoor microenvironments, as well as their temporal trends were first reported in this study, which will provide a basis for more accurate FR exposure assessments in the future.

Laboratory Performance of Hot Mix Asphalt with High Reclaimed Asphalt Pavement (RAP) and Fine Reclaimed Asphalt Pavement (FRAP) Content.

Recently, there has been an increasing interest in the applications of recycled mixtures with a high reclaimed asphalt pavement (RAP) content. However, many government departments are hesitant about the applications of that due to being worried about the durability of its pavement, and few findings has been reported in terms of the percentage of fine reclaimed asphalt pavement (FRAP, 0~5 mm) in recycled mixtures. In this paper, 25% or more RAP by the weight of aggregates is defined as high RAP and high FRAP refers to 10% or more FRAP by the weight of aggregates. This paper examines the laboratory performances of mixtures with high RAP (30%, 40%, and 50%) and FRAP (10%, 15%, and 20%). Performance evaluations have been conducted by conventional tests, including the low-temperature bending test, fatigue test, and the moisture susceptibility test. The results show that with the increasing RAP and FARP contents, 41% (30-R-10) to 63% (50-R-15) of virgin asphalt can be saved, both the low-temperature and fatigue performance decrease, and the moisture performance firstly increases and then decreases. The results of analysis of variance (ANOVA) in terms of low-temperature and moisture performance show that RAP contents in recycled mixtures have a significant effect on the performance, while the effect of FRAP contents on the performance of recycled mixtures is insignificant.

Influence of Air Pollution on Inhalation and Dermal Exposure of Human to Organophosphate Flame Retardants: A Case Study During a Prolonged Haze Episode.

The health impact of haze is of great concern, but few studies have explored its influence on human inhalation and dermal exposure to trace pollutants. Size-segregated atmospheric particles ( n = 72) and forehead wipe samples ( n = 80) from undergraduates were collected in Xinxiang, China, during a prolonged haze episode and analyzed for 10 organophosphate flame retardants (OPFRs). ∑TCPP and TCEP were the most abundant OPFR substances in all samples. The arithmetic mean particle-bound and forehead OPFR concentrations under a heavy pollution condition (air quality index (AQI), 350-550) were 41.9 ng/m3 (∑8OPFRs) and 7.4 µg/m2 (∑6OPFRs), respectively, apparently greater than the values observed under a light pollution condition (AQI, 60-90) (19.5 ng/m3 and 3.9 µg/m2, respectively). Meteorological conditions played distinctive roles in affecting the OPFR occurrence in atmospheric particles (statistically significant for TCEP and ∑TCPP) and forehead wipes (excluding TPHP), implying that OPFR exposure through inhalation and dermal absorption was synchronously influenced by air quality, and OPFRs on the forehead may be mainly absorbed from the air. Inhalation contributed dominantly to the total OPFR exposure dose for humans when using the relative absorption method to assess dermal exposure, while according to the permeability coefficient method, dermal exposure was much more significant than inhalation. The results of this study indicate that OPFR exposure should attract particular concern in regions with heavy air pollution.

The non-negligible environmental risk of recycling halogenated flame retardants associated with plastic regeneration in China.

To investigate halogenated flame retardant (HFR) contents in recycled plastic materials, 23 recycled plastic samples manufactured in five Chinese provinces were randomly purchased online, and the ∑12HFR concentrations of these samples (including 8 polybrominated diphenyl ethers (PBDEs, BDE 28, 47, 99, 100, 154, 153, 183 and 209), decabromodiphenylethane (DBDPE), 1,2-bis(2,4,6-tribromophenoxy)ethane (BTBPE), and 2 dechlorane plus isomers (DP, syn-DP and anti-DP)) varied from ND to 169,000 ng g-1 (mean ±â€¯SD, 46,900 ±â€¯44,700 ng g-1). BDE 209 and DBDPE were the dominant components and their concentration ranges were from ND to 106,000 ng g-1 and ND to 81,900 ng g-1, respectively. Generally, the HFR content and plastic variety closely correlate, and the ∑HFR concentrations in the polyvinyl chloride (PVC, N = 5), polypropylene (PP, N = 9), acrylonitrile butadiene styrene (ABS, N = 5), polystyrene (PS, N = 1) and polyethylene (PE, N = 3) samples were 65,300 ±â€¯42,400, 36,700 ±â€¯56,000, 30,000 ±â€¯25,200, 24,300 and 4330 ±â€¯7500 ng g-1, respectively. The HFR abundance in plastic from Guangdong (76,000 ±â€¯56,400 ng g-1, N = 7) and Hebei (37,500 ±â€¯11,500 ng g-1, N = 4) was much higher than that for other provinces/cities.

Estimation of Exposure to Organic Flame Retardants via Hand Wipe, Surface Wipe, and Dust: Comparability of Different Assessment Strategies.

This study aimed to investigate the exposure of three occupational populations (i.e., office worker, taxi drivers, and security guards) to flame retardants by comparing different sampling approaches (i.e., hand wipe, surface wipe, and dust). Hand wipe samples were collected from 68 participants from three populations in Beijing, China. Dust and/or surface wipes were also sampled from their respective occupational workplaces. Ten phosphorus flame retardants (PFRs), two novel brominated flame retardants (NBFRs) and eight polybrominated diphenyl ethers (PBDEs) were analyzed. BDE209, decabromodiphenylethane (DBDPE), tris(chloropropyl) phosphate isomers (∑TCPP), tris(2-chloroethyl) phosphate (TCEP) and triphenyl phosphate (TPHP) were detected in at least 95% of the samples, collectively accounting for over 90% of the total concentrations in each type of samples. Concentrations and composition profiles of flame retardants differed in hand wipes of the three populations with summed level of all target compounds (∑FRs) ranked as taxi drivers > office workers > security guards. Most FRs in hand wipes were significantly correlated with those in surface wipes, whereas the correlations between hand wipes and dust are weak. Estimated exposure to FRs via dust ingestion and dermal absorption for each population varied when using different types of samples for exposure assessment, suggesting the importance of sampling strategy selection. Estimation via hand wipes indicated that taxi drivers were subjected to greater exposure to PFRs among three populations, while office workers were subjected to greater BFR exposure. Our data suggest hand wipes have the potential of being standardized into a noninvasive method for evaluating human exposure to environmental contaminants across different populations.