Multiple comparisons of organic,microbial, and fine particulate pollutants in typical indoor environments: Diurnal and seasonal variations

This study was performed to investigate the possible sources as well as seasonal and diurnal variations of indoor air pollutants in widely used four different environments (house, office, kindergarten, and primary school) in which people spend most of their time. Bioaerosol levels and species, volatile organic compound (VOC) levels, and PM_2.5 (particulate matter with an aerodynamic diameter ≤2.5 μm) levels were determined in different parts of these environments in parallel with outdoor sampling. Air pollution samplings were carried out in each microenvironment during five subsequent days in both winter and summer in Ankara, Turkey. The results indicated that bioaerosol, VOC, and PM_2.5 levels were higher in the winter than in the summer. Moreover, PM_2.5 and bioaerosol levels showed remarkable daily and diurnal variations, whereas a good correlation was found between the VOC levels measured in the morning and in the afternoon. Bacteria levels were, in general, higher than fungi levels. Among the VOCs, toluene was the most predominant, whereas elevated n-hexane levels were also observed in the kindergarten and the primary school, probably due to the frequent wet cleaning during school days. According to factor analysis, several factors were found to be significantly influencing the indoor air quality (IAQ), and amongst them, VOC-based products used indoors ranked first. The overall results indicate that grab sampling in naturally ventilated places may overestimate or underestimate the IAQ due to the inhomogeneous composition of indoor air caused by irregular exchanges with the outdoor air according to the season and/or occupants' habits.

Implications Seasonal and diurnal variations of VOCs, PM_2.5, bioaerosols in house, office, and schools were observed, in which PM_2.5 and bioaeorosols showed marked both intra- and interday variability, but VOCs did not. VOC-containing products were the most common source of air pollutants affecting the indoor air quality. External factors affecting the indoor air quality were season and indirectly ventilation. A grab sample cannot be representative in evaluating the air quality of a naturally ventilated environment precisely.     

Mitigation of odor causing emissions—Bench-scale investigation

Emissions of malodors are considered to be the greatest threat to the compost industry. In work presented here, several simple odor mitigation alternatives were investigated for their effectiveness in preventing the release of common odorants, such as terpenes, ammonia, and reduced sulfur compounds. The mitigation methods studied included the use of a blanket of finished compost, compost amendment mixed within the feedstock, odor neutralizing agents (ONAs), and oxygen release compounds (ORCs). Among the mitigation alternatives investigated in this study, the use of finished compost as a blanket and finished compost as an amendment yielded the most conclusive and significant results. Both of these alternatives yielded a substantial emission reduction for terpenes, ammonia, and reduced sulfur compounds. The application of finished compost blanket resulted in up to 95% reduction of terpene and 25% reduction of ammonia emissions. Blending the feedstock with finished compost also provided substantial reduction of terpene emissions ranging from 73.6 to 93.1% at the 24% blending ratio, and up to 85% ammonia reduction a the 35% blending ratio. Use of finished compost also provided 75% lower reduced sulfur compound emissions at the 12% blending ratio. Misting and application of odor neutralizing agents did not result in any consistent reduction in emissions for any of the odorous compounds tested.

Implications The odor emissions from composting are often considered to be the biggest threat to composting facilities. Because most facilities cannot afford enclosures and contained composting vessels, there is a need to inexpensively and effectively control the odor emissions from composting facilities. The findings of this research can lead the way for efforts to control odor easily and cost effectively. In fact, the application of a compost blanket for odor control is already gaining acceptance by the composting industry.     

Radical precursors and related species from traffic as observed and modeled at an urban highway junction

Nitrous acid (HONO) and formaldehyde (HCHO) are important precursors for radicals and are believed to favor ozone formation significantly. Traffic emission data for both compounds are scarce and mostly outdated. A better knowledge of today's HCHO and HONO emissions related to traffic is needed to refine air quality models. Here the authors report results from continuous ambient air measurements taken at a highway junction in Houston, Texas, from July 15 to October 15, 2009. The observational data were compared with emission estimates from currently available mobile emission models (MOBILE6; MOVES [MOtor Vehicle Emission Simulator]). Observations indicated a molar carbon monoxide (CO) versus nitrogen oxides (NO_x) ratio of 6.01 ± 0.15 (r ² = 0.91), which is in agreement with other field studies. Both MOBILE6 and MOVES overestimate this emission ratio by 92% and 24%, respectively. For HCHO/CO, an overall slope of 3.14 ± 0.14 g HCHO/kg CO was observed. Whereas MOBILE6 largely underestimates this ratio by 77%, MOVES calculates somewhat higher HCHO/CO ratios (1.87) than MOBILE6, but is still significantly lower than the observed ratio. MOVES shows high HCHO/CO ratios during the early morning hours due to heavy-duty diesel off-network emissions. The differences of the modeled CO/NO_x and HCHO/CO ratios are largely due to higher NO_x and HCHO emissions in MOVES (30% and 57%, respectively, increased from MOBILE6 for 2009), as CO emissions were about the same in both models. The observed HONO/NO_x emission ratio is around 0.017 ± 0.0009 kg HONO/kg NO_x which is twice as high as in MOVES. The observed NO₂/NO_x emission ratio is around 0.16 ± 0.01 kg NO₂/kg NO_x, which is a bit more than 50% higher than in MOVES. MOVES overestimates the CO/CO₂ emission ratio by a factor of 3 compared with the observations, which is 0.0033 ± 0.0002 kg CO/kg CO₂. This as well as CO/NO_x overestimation is coming from light-duty gasoline vehicles.

Implications: Nitrous acid (HONO) and formaldehyde (HCHO) are important precursors for radicals that ultimately contribute to ozone formation. There still exist uncertainties in emission sources of HONO and HCHO and thus regional air quality modeling still tend to underestimate concentrations of free radicals in the atmosphere. This paper demonstrates that the latest U.S. Environmental Protection Agency (EPA) traffic emission model MOVES still shows significant deviations from observed emission ratios, in particular underestimation of HCHO/CO and HONO/NO_x ratios. Improving the performance of MOVES may improve regional air quality modeling.     

The structure of the fire fighting foam surfactant Forafac®1157 and its biological and photolytic transformation products

For several decades, perfluorooctane sulfonate (PFOS) has widely been used as a fluorinated surfactant in aqueous film forming foams used as hydrocarbon fuel fire extinguishers. Due to concerns regarding its environmental persistence and toxicological effects, PFOS has recently been replaced by novel fluorinated surfactants such as Forafac®1157, developed by the DuPont company. The major component of Forafac®1157 is a 6:2 fluorotelomer sulfonamide alkylbetaine (6:2 FTAB), and a link between the trade name and the exact chemical structure is presented here to the scientific community for the first time. In the present work, the structure of the 6:2 FTAB was elucidated by ¹H, ¹³C and ¹⁹F nuclear magnetic resonance spectroscopy and high-resolution mass spectrometry. Moreover, its major metabolites from blue mussel (Mytilus edulis) and turbot (Scophthalmus maximus) and its photolytic transformation products were identified. Contrary to what has earlier been observed for PFOS, the 6:2 FTAB was extensively metabolized by blue mussel and turbot exposed to Forafac®1157. The major metabolite was a deacetylated betaine species, from which mono- and di-demethylated metabolites also were formed. Another abundant metabolite was the 6:2 fluorotelomer sulfonamide. In another experiment, Forafac®1157 was subjected to UV-light induced photolysis. The experimental conditions aimed to simulate Arctic conditions and the deacetylated species was again the primary transformation product of 6:2 FTAB. A 6:2 fluorotelomer sulfonamide was also formed along with a non-identified transformation product. The environmental presence of most of the metabolites and transformation products was qualitatively demonstrated by analysis of soil samples taken in close proximity to an airport fire training facility.     

Characterization of silver release from commercially available functional (nano)textiles

Silver, both in the nano as well as in other forms, is used in many applications including antimicrobial textiles. Washing of such textiles has already been identified as an important process that results in the release of silver into wastewater. This study thus investigated the release of silver from eight different commercially available silver-textiles during a washing and rinsing cycle. The silver released was size-fractionated and characterized using electron microscopy. In addition, the antimicrobial functionality of the textiles was tested before and after washing. Three of the textiles contained nanosized silver (labeled or confirmed by manufacturers’ information), another used a metallic silver wire and four contained silver in undeclared form. The initial silver content of the textiles was between 1.5 and 2925 mg Ag/kg. Only four of the investigated textiles leached detectable amounts of silver, of which 34-80% was in the form of particles larger than 450 nm. Microscopic analysis of the particles released in the washing solutions identified Ti/Si-AgCl nanocomposites, AgCl nanoparticles, large AgCl particles, nanosilver sulfide and metallic nano-Ag, respectively. The nanoparticles were mainly found in highly agglomerated form. The identified nanotextiles showed the highest antimicrobial activity, whereas some of the other textiles, e.g. the one with a silver wire and the one with the lowest silver content, did not reduce the growth of bacteria at all. The results show that different silver textiles release different forms of silver during washing and that among the textiles investigated AgCl was the most frequently observed chemical form in the washwater.     

Captopril and its dimer captopril disulfide: photodegradation, aerobic biodegradation and identification of transformation products by HPLC-UV and LC-ion trap-MS(n)

In some countries effluents from hospitals and households are directly emitted into open ditches without any further treatment and with very little dilution. Under such circumstances photo- and biodegradation in the environment can occur. However, these processes do not necessarily end up with the complete mineralization of a chemical. Therefore, the biodegradability of photoproduct(s) by environmental bacteria is of interest. Cardiovascular diseases are the number one cause of death globally. Captopril (CP) is used in this study as it is widely used in Egypt and stated as one of the essential drugs in Egypt for hypertension. Three tests from the OECD series were used for biodegradation testing: Closed Bottle test (CBT; OECD 301 D), Manometric Respirometry test (MRT; OECD 301 F) and the modified Zahn-Wellens test (ZWT; OECD 302 B). Photodegradation (150 W medium-pressure Hg-lamp) of CP was studied. Also CBT was performed for captopril disulfide (CPDS) and samples received after 64 min and 512 min of photolysis. The primary elimination of CP and CPDS was monitored by LC-UV at 210 nm and structures of photoproducts were assessed by LC-UV-MS/MS (ion trap). Analysis of photodegradation samples by LC-MS/MS revealed CP sulfonic acid as the major photodegradation product of CP. No biodegradation was observed for CP, CPDS and of the mixture resulting from photo-treatment after 64 min in CBT. Partial biodegradation in the CBT and MRT was observed in samples taken after 512 min photolysis and for CP itself in MRT. Complete biodegradation and mineralization of CP occurred in the ZWT.     

Toxic effects of deltamethrin and λ-cyhalothrin on Xenopus laevis tadpoles

This study evaluates the toxic effects of deltamethrin and λ-cyhalothrin on Xenopus laevis tadpoles after 168 h of exposure. The LC(50) of deltamethrin and λ-cyhalothrin at 168 h was calculated as the μg of active ingredient per liter (μg AI/L). According to these values, the LC(50) was 6.26 and 3.94 μg AI/L for deltamethrin and λ-cyhalothrin, respectively. Several enzymes were studied for early signs of intoxication following exposure to the pesticides for 24 h. Glutathione-S-transferase,carboxylesterase, and lactate dehydrogenase were inhibited by λ-cyhalothrin, and both pesticides inhibited acid phosphatase and aspartate aminotransferase. In contrast, acetylcholinesterase was activated by deltamethrin. The results suggest that X. laevis is sensitive to the pyrethroids that were tested, and the enzyme responses suggest that they are potential biomarkers for evaluating the toxic effect of pyrethroids on amphibians in environmental conditions.     

Monitoring of hexabromocyclododecane diastereomers in fish from European freshwaters and estuaries

Background and aims  

Hexabromocyclododecane (HBCD) is a brominated flame retardant used mainly in polystyrene foam as well as in textile applications. In recent years, measures were taken to reduce HBCD emissions during its production and use. To evaluate the efficacy of these measures, a monitoring project was initiated with fish as bioaccumulation indicators.     

Exposure to toxic waste containing high concentrations of hydrogen sulphide illegally dumped in Abidjan, C?te d’Ivoire

Introduction

On August 2006, a cargo ship illegally dumped 500?t of toxic waste containing high concentrations of hydrogen sulphide in numerous sites across Abidjan. Thousands of people became ill. Seventeen deaths were associated with toxic waste exposure.

Materials and methods

This study reports on environmental and health problems associated with the incident. A cross-sectional transect study was conducted in five waste dumping site areas.

Results

Of the households, 62.1% (n?=?502) were exposed to the effects of the pollutants and 51.1% of the interviewed people (n?=?2,368) in these households showed signs of poisoning. Most important symptoms were cough (37.1%), asthenia (33.1%), pruritus (29.9%) and nausea (29.1%).

Discussion

The health effects showed different frequencies in the five waste impact sites. Among the poisoned persons, 21.1% (n?=?532) presented symptoms on the survey day (i.e., 4?months after incident). Transect sampling allowed to determine a radius of vulnerability to exposure of up to 3?km from the point of toxic waste disposal.

Conclusion

The area of higher vulnerability is influenced by various environmental factors, such as size and severity of pollution site, duration of toxic waste pollution on the impact site and locally climatic conditions. The surveillance of effects on environment and human health is warranted to monitor the development.     

Effect of diurnal changes in VOC source strengths on performances of receptor models

Introduction

The effect of diurnal changes in strengths of volatile organic compound (VOC) sources on the performances of positive matrix factorization (PMF) and principal component analysis (PCA) was investigated using ambient measurement results that were taken during daytime and nighttime hours between March 24 and May 14, 2011, within Davutpasa Campus of Yildiz Technical University (Istanbul, Turkey).

Methods

Forty-five VOC species, ranging from C₅ to C₁₁ in volatility, were measured in the samples, 40 of which are included in the analyses. Ambient samples were grouped as daytime, nighttime, and all day datasets, and both PMF and PCA were applied to each dataset. A total of six source groups were extracted from each dataset: solvent use, general industrial paint use, gasoline and diesel vehicle exhausts, and biogenic as well as evaporative emissions. Estimated source contributions showed great diurnal variations.

Results

The results suggested that extraction of possible sources by PCA depends greatly on the number of samples and the strength of the sources, while PMF produced stable results regardless of number of samples and source strengths.

Conclusion

Although PMF was unable to resolve gasoline vehicle and evaporative emissions, it was found to be successful in explaining diurnal fluctuations in source strengths, while the performance of PCA depends on the strength of emission source.