Source Of Formaldehyde Research Articles

Polyethylene glycol promoted Cs/Zr-SiO2 bifunctional catalyst for aldol condensation of methyl propionate and formaldehyde to methyl methacrylate

The production of methyl methacrylate (MMA) via one-step gaseous aldol condensation of methyl propionate (MP) and formaldehyde (FA) has received wide attention. Herein, series of polyethylene glycol (PEG) promoted Cs-Zr/SiO2 catalysts were developed and characterized by XRD, FT-IR, HR-TEM, BET, NH3–/CO2-TPD and Py-IR etc. The dispersion of active acid and base sites and their balance in catalyst could be significantly improved with the addition of PEG, which facilitated the activation of reactants and conversion towards product MMA. Furthermore, the relationship between the acid-base properties and catalytic performance was revealed, the acid and base sites were responsible for the decomposition of trioxane, which was used as the source of FA, and transformation of MP, respectively. The in-situ DRIFTS experiments unraveled two catalytic pathways through the synergistic effects between the acid and base sites during the aldol condensation of MP with FA to MMA. Kinetic studies revealed that the activation energy of this aldol condensation on the optimal catalyst is 97.9 kJ/mol, with the reaction order of 0.98 and 1.18 corresponding to MP and FA. Deactivation behavior studies demonstrated that the decrease of catalytic activity as a function of time-on-stream was resulting from the deposition of predominant amorphous carbon instead of the loss of active components.

The chemical characteristics and sources of formaldehyde on O3 and non-O3 polluted days in Wuhan, central China

In August 2023, a detailed investigation of formaldehyde (HCHO) chemical characteristics on ozone (O3) polluted days and non-O3 polluted days in Wuhan was undertaken. The mean value of HCHO on O3 polluted days (3.02 ± 1.15 ppbv) was 122% higher than that on non-O3 polluted days (1.35 ± 0.41 ppbv). Utilizing Positive Matrix Factorization (PMF) model revealed secondary formation as the dominant HCHO source (58.3% on non-O3 polluted days and 66.2% on O3 polluted days). On O3 polluted days, the contribution of liquefied petroleum gas (LPG)/solvent usage and industrial emissions to HCHO were 13.7% and 8.2%, respectively, whereas on non-O3 polluted days, LPG/solvent use and diesel exhaust contributed 15.4% and 14.7%, respectively. The top ten species, with the highest Relative Incremental Reactivity (RIR) to HCHO, were mainly alkenes and aromatics, which remained consistent on both O3 and non-O3 polluted days. It is noteworthy that the RIR of isobutane to HCHO is significant in this study. Further reapportionment of secondary HCHO by a photochemical box model indicated that LPG/solvent usage (33.2%) contributed the most to HCHO on O3 polluted days, while diesel exhaust (31.9%) dominated on non-O3 polluted days. This research enhances understanding of HCHO in Wuhan, providing a theoretical basis for targeted pollution reduction and supporting efforts to improve air quality and public health.

Marine sources of formaldehyde in the coastal atmosphere

Elevated concentrations of formaldehyde and other carbonyl compounds are frequently observed in the marine atmosphere but are often significantly underestimated by atmospheric models. To evaluate the potential impact of marine sources on atmospheric formaldehyde, high-resolution measurements were conducted at a coastal site (∼15 m from the sea) during the summer in Qingdao, China. Observed formaldehyde levels averaged 2.4 ± 0.9 ppbv (1 ppbv = 10–9 L L–1), with peaks reaching 6.8 ppbv. Backward trajectories indicate that formaldehyde concentrations remained high in marine air masses. Formaldehyde exhibited weak correlations with primary pollutants such as NO and CO but showed strong correlations with marine tracers, notably methyl ethyl ketone and 1-butene. Chamber experiments confirmed that the photodecomposition of Enteromorpha released large amounts of formaldehyde and marine tracer species. When normalized to acetylene, the levels of formaldehyde, 1-butene, and MEK increased by factors of 3.8, 8.1, and 3.5, respectively. Results from an observation-based chemical box model simulation, which utilizes the Master Chemical Mechanism (MCM), revealed that formaldehyde contributes 56% to the primary source of HO2 radicals, while neglecting formaldehyde chemistry would lead to a 15% reduction in coastal ozone production rates. This study interlinks oceanic biology and atmospheric chemistry, advancing the understanding of the ocean’s role as a significant source of organic compounds and its contribution to carbon cycling.

Molecular Electrochemical Catalysis of CO-to-Formaldehyde Conversion with a Cobalt Complex.

Formox, a highly energy-intensive process, currently serves as the primary source of formaldehyde (HCHO), for which there is a crucial and steadily growing chemical demand. The alternative electrochemical production of HCHO from C1 carbon sources such as CO2 and CO is still in its early stages, with even the few identified cases lacking mechanistic rationalization. In this study, we demonstrate that cobalt phthalocyanine (CoPc) immobilized on multiwalled carbon nanotubes (MW-CNTs) constitutes an excellent electrocatalytic system for producing HCHO with productivity through the direct reduction of CO, the two-electron reduction product of CO2. By carefully adjusting both the pH and the applied potential, we identified conditions that enable the production of HCHO with a partial current density of 0.64 mA cm-2 (17.5% Faradaic efficiency, FE) and a total FE of 61.2% for the liquid products (formaldehyde and methanol). A reduction mechanism is proposed.

Comparison of three source apportionment methods based on observed and initial HCHO in Taiyuan, China

Identifying the sources of formaldehyde (HCHO) is key to reducing the pollution of HCHO and ozone (O3) on the ground level. Using the same datasets applied to the positive matrix factorization (PMF) model by (Hua et al., 2023), the initial concentrations of HCHO were estimated using the photochemical age and the sources of observed and initial HCHO were apportioned based on multiple linear regression (MLR) and photochemical age-based parameterization (PCAP) methods. These results suggest that the source of the initial HCHO can better reflect its contribution. The secondary formation contributed to 49.3–69.1 % of initial HCHO at four sites in Taiyuan based on MLR, which was higher (7.4–36.2 %) than the contributions of secondary formation from observed HCHO. The HCHO was mainly affected by anthropogenic secondary (10.8–34.4 %) and background sources (17.4–78.7 %) based on the PCAP method. We compared the results of the HCHO sources from the MLR, PCAP, and PMF models under photochemical loss. There was good agreement among the emission ratios of acetylene-based HCHO obtained by the different methods at the four sites. The correlation analysis of different source apportionment methods illustrated that primary emissions from the PCAP and the MLR model had the greatest correlation (0.22–0.60). Secondary formations from the PMF and MLR models showed good correlations at all four sites, with R values ranging from 0.42 to 0.83. The HCHO peak of diurnal variation simulated by MLR appeared late compared to the other methods, and the difference in daily variation of HCHO from the PMF model was significantly higher than that of PCAP and MLR. The overlapping conclusions of different source apportionment methods should be considered and used to guide efforts to improve air quality.

Choline degradation in Paracoccus denitrificans: identification of sources of formaldehyde.

Paracoccus denitrificans is a facultative methylotroph that can grow on methanol and methylamine as sole sources of carbon and energy. Both are oxidized to formaldehyde and then to formate, so growth on C1 substrates induces the expression of genes encoding enzymes required for the oxidation of formaldehyde and formate. This induction involves a histidine kinase response regulator pair (FlhSR) that is likely triggered by formaldehyde. Catabolism of some complex organic substrates (e.g., choline and L-proline betaine) also generates formaldehyde. Thus, flhS and flhR mutants that fail to induce expression of the formaldehyde catabolic enzymes cannot grow on methanol, methylamine, and choline. Choline is oxidized to glycine via glycine betaine, dimethylglycine, and sarcosine. By exploring flhSR growth phenotypes and the activities of a promoter and enzyme known to be upregulated by formaldehyde, we identify the oxidative demethylations of glycine betaine, dimethylglycine, and sarcosine as sources of formaldehyde. Growth on glycine betaine, dimethylglycine, and sarcosine is accompanied by the production of up to three, two, and one equivalents of formaldehyde, respectively. Genetic evidence implicates two orthologous monooxygenases in the oxidation of glycine betaine. Interestingly, one of these appears to be a bifunctional enzyme that also oxidizes L-proline betaine (stachydrine). We present preliminary evidence to suggest that growth on L-proline betaine induces expression of a formaldehyde dehydrogenase distinct from the enzyme induced during growth on other formaldehyde-generating substrates.IMPORTANCEThe bacterial degradation of one-carbon compounds (methanol and methylamine) and some complex multi-carbon compounds (e.g., choline) generates formaldehyde. Formaldehyde is toxic and must be removed, which can be done by oxidation to formate and then to carbon dioxide. These oxidations provide a source of energy; in some species, the CO2 thus generated can be assimilated into biomass. Using the Gram-negative bacterium Paracoccus denitrificans as the experimental model, we infer that oxidation of choline to glycine generates up to three equivalents of formaldehyde, and we identify the three steps in the catabolic pathway that are responsible. Our work sheds further light on metabolic pathways that are likely important in a variety of environmental contexts.

Asymmetric Organocatalyzed Transfer Hydroxymethylation of Isoindolinones Using Formaldehyde Surrogates.

The piperidine-based Takemoto catalyst has been successfully employed in a novel asymmetric transfer hydroxymethylation of activated isoindolinones, allowing us to prepare the enantioenriched hydroxymethylated adducts in good to excellent yields (48-96%) and enantiopurities (81:19-97:3 e.r.). To increase the reaction rate without compromising the selectivity, carefully optimized formaldehyde surrogates were employed, providing a convenient source of anhydrous formaldehyde with a base-triggered release. The substrate scope, including 34 entries, showed the considerable generality of the asymmetric transformation, and most entries exhibited complete conversions in 24-48 h. A scale-up experiment and multiple enantioselective downstream transformations were also carried out, suggesting the prospective synthetic utility of the products.

Source and variability of formaldehyde in the Fenwei Plain: An integrated multi-source satellite and emission inventory study

Formaldehyde (HCHO) is a high-yield product of the oxidation of volatile organic compounds (VOCs) released by anthropogenic activities, fires, and vegetations. Hence, we examined the spatiotemporal variation trends in HCHO columns observed using the Ozone Monitoring Instrument (OMI) during 2005–2021 across the Fenwei Plain (FWP) and analysed the source and variability of HCHO using multi-source data, such as thermal anomalies. The spatial distribution of the annual mean HCHO in the FWP increased from northwest to southeast during 2005–2021, and the high-value aggregation areas contracted and gradually clustered, forming a belt-shaped distribution area from Xi'an to Baoji, north of the Qinling Mountains. The annual mean HCHO concentration generally showed a two-step increase over the 17 years. Fires showed a single-peak trend in March and a double-peak M-shaped trend in March and October, whereas urban thermal anomalies (UTAs) showed an inverted U-shaped trend over 17 years, with peaks occurring in May. The HCHO peaks are mainly caused by the alternating contributions of fires and UTAs. The fires and UTAs (predominantly industrial heat sources) played a role in controlling the background level of HCHO in the FWP. Precipitation and temperature were also important influencing variables for seasonal variations, and the influence of plant sources on HCHO concentrations had significant regional characteristics and contributions. In addition, the FWP has poor dispersion conditions and is an aggregated area for the long-range transport of air pollutants.

What are the DNA lesions underlying formaldehyde toxicity?

Formaldehyde is a highly reactive organic compound. Humans can be exposed to exogenous sources of formaldehyde, but formaldehyde is also produced endogenously as a byproduct of cellular metabolism. Because formaldehyde can react with DNA, it is considered a major endogenous source of DNA damage. However, the nature of the lesions underlying formaldehyde toxicity in cells remains vastly unknown. Here, we review the current knowledge of the different types of nucleic acid lesions that are induced by formaldehyde and describe the repair pathways known to counteract formaldehyde toxicity. Taking this knowledge together, we discuss and speculate on the predominant lesions generated by formaldehyde, which underly its natural toxicity.

Spatio-temporal trend analysis of air pollutants during COVID-19 over Korba district, Chhattisgarh (India) using Google Earth Engine

Air pollution is a significant public health concern and impacts a country’s well-being. The COVID-19 pandemic and subsequent lockdowns have provided researchers with a unique opportunity to examine the impact of human activities and industries on air pollution. The annual mean PM2.5 grids were validated by comparing them with collocated surface in situ PM2.5 measurements and were then used for trend analyses. Using ground in-situ data validated in 2020–21 showed a good correlation (R2 = 0.90, 0.81 & 0.99) with Satellite-derived for summer, monsoon, and winter seasons, respectively. Among these pollutants, human and industrial activities are a significant source of Sulfur dioxide (SO2), Nitrogen dioxide (NO2), Formaldehyde (HCHO), and Ozone (O3). This study examined how these pollutants changed between February 2019 to January 2022 in Korba District, Chhattisgarh (India). The Google Earth Engine (GEE) is based on the cloud platform time series from the Sentinel-5P TROPOMI satellite data sets. The findings show that the annual average concentration of (SO2: R2 = 0.90, 0.97, and 0.97), (NO2: R2 = 0.97, 0.94, and 0.94), (HCHO: R2 = 0.99, 0.99, and 0.99), and (O3: R2 = 0.99, 0.94, and 0.94) and also increased monsoon, summer, and winter in ascending order for 2019–20, 2020–21, and 2021–22 respectively, due to topology, meteorology, and anthropogenic activities. These results are essential guidelines for future industrial, transportation, and traffic management as sustainable development legislation and programs. Additionally, by applying the COVID-19 scenario, it is now feasible to research how industrial activities, transportation, and biomass burning are, compounded by the region’s topography, affecting air quality using free satellite-derived data sets. These findings also benefit future policy choices on dealing with viral proliferation and reducing its negative societal and economic repercussions.

Engineering a synthetic energy-efficient formaldehyde assimilation cycle in Escherichia coli

One-carbon (C1) substrates, such as methanol or formate, are attractive feedstocks for circular bioeconomy. These substrates are typically converted into formaldehyde, serving as the entry point into metabolism. Here, we design an erythrulose monophosphate (EuMP) cycle for formaldehyde assimilation, leveraging a promiscuous dihydroxyacetone phosphate dependent aldolase as key enzyme. In silico modeling reveals that the cycle is highly energy-efficient, holding the potential for high bioproduct yields. Dissecting the EuMP into four modules, we use a stepwise strategy to demonstrate in vivo feasibility of the modules in E. coli sensor strains with sarcosine as formaldehyde source. From adaptive laboratory evolution for module integration, we identify key mutations enabling the accommodation of the EuMP reactions with endogenous metabolism. Overall, our study demonstrates the proof-of-concept for a highly efficient, new-to-nature formaldehyde assimilation pathway, opening a way for the development of a methylotrophic platform for a C1-fueled bioeconomy in the future.

Sources of Formaldehyde in U.S. Oil and Gas Production Regions

Sources of Formaldehyde in U.S. Oil and Gas Production Regions

Evolution Characteristics of Atmospheric Formaldehyde Emissions in Guangdong Province from 2006 to 2020

Atmospheric formaldehyde, a key precursor for ozone (O3) and secondary PM2.5, is carcinogenic and plays an important role in atmospheric photochemistry and the formation of secondary pollution. However, the lack of understanding of the emission sources of atmospheric formaldehyde limits the study on the formation mechanism of secondary pollution and the formulation of pollution control strategies. This study used the emission factor and source profile methods to establish the emission inventories of formaldehyde in Guangdong Province from 2006 to 2020 and identified the main emission sources of formaldehyde and spatial and temporal evolution characteristics. The results showed that the formaldehyde emissions in Guangdong Province fluctuated in the range of 39000-56000 tons during 2006 to 2020, exhibiting a very weak downward trend. Biomass combustion is an important source of formaldehyde emission in Guangdong Province, of which the contribution decreased from 58% in 2006 to 27% in 2020 owing to effective control measures implemented in Guangdong Province. The solvent use source became the predominant emission source of formaldehyde in 2020 by contributing up to 28%, primarily through plastic products and asphalt paving sources. The construction machinery and trucks fueled by diesel were important contributors of formaldehyde emissions from mobile sources. Although the formaldehyde emissions in the Pearl River Delta and the non-Pearl River Delta were equivalent, the spatial distributions showed that formaldehyde emission hotspots were concentrated in the center of the Pearl River Delta and the eastern and western areas of the non-Pearl River Delta. This was primarily because the solvent use and mobile sources were the main sources of formaldehyde emissions in the Pearl River Delta, whereas the biomass combustion source was the dominant source in the non-Pearl River Delta. Therefore, the formaldehyde emission mitigations of the industrial and mobile sources in the central region of the Pearl River Delta and the biomass combustion source in the western area of Guangdong should be further strengthened in the future.

Investigation of formaldehyde sources and its relative emission intensity in shipping channel environment

Formaldehyde (HCHO) is considered one of the most abundant gas-phase carbonyl compounds in the atmosphere, which can be directly emitted through transportation sources. Long-Path Differential Optical Absorption Spectroscopy (LP-DOAS) was used to observe HCHO in the river channel of Wusong Wharf in Shanghai, China for the whole year of 2019. Due to the impact of ship activity, the annual average HCHO level in the channel is about 2.5 times higher than that in the nearby campus environment. To explain the sources of HCHO under different meteorological conditions, the tracer-pair of CO and Ox (NO2+O3) was used on the clustered air masses. The results of the source appointment show that primary, secondary and background account for 24.14% (3.34 ± 1.19 ppbv), 44.78% (6.20 ± 2.04 ppbv) and 31.09% (4.31 ± 2.33 ppbv) of the HCHO in the channel when the air masses were from the mixed direction of the city and channel, respectively. By performing background station subtraction at times of high primary HCHO values and resolving the plume peaks, directly emitted HCHO/NO2 in the channel environment and plume were determined to be mainly distributed between 0.2 and 0.3. General cargo ships with higher sailing speeds or main engine powers tend to have higher HCHO/NO2 levels. With the knowledge of NO2 (or NOx) emission levels from ships, this study may provide data support for the establishment of HCHO emission factors.

Residential exposure to air pollution and adverse respiratory and allergic outcomes in children and adolescents living in a chipboard industrial area of Northern Italy

BackgroundChipboard production is a source of wood dust, formaldehyde, and combustion-related pollutants such as nitrogen dioxide (NO2) and particulate matter (PM). In this cohort study, we assessed whether exposures to NO2, formaldehyde, PM10, PM2.5, and black carbon were associated with adverse respiratory and allergic outcomes among all 7525 people aged 0–21 years residing in the Viadana district, an area in Northern Italy including the largest chipboard industrial park in the country. MethodsData on hospitalizations, emergency room (ER) admissions, and specialist visits in pneumology, allergology, ophthalmology, and otorhinolaryngology were obtained from the Local Health Unit. Residential air pollution concentrations in 2013 (baseline) were derived using local (Viadana II), national (EPISAT), and continental (ELAPSE) exposure models. Associations were estimated using negative binomial regression models for counts of events occurred during 2013–2017, with follow-up time as an offset term and adjustment for sex, age, nationality, and a census-block socio-economic indicator. ResultsMedian annual exposures to NO2, PM10, and PM2.5 were below the European Union annual air quality standards (40, 40, and 25 μg/m3) but above the World Health Organization 2021 air quality guideline levels (10, 15, and 5 μg/m3). Exposures to NO2 and PM2.5 were significantly associated with higher rates of ER pneumology admissions (13 to 30 % higher rates per interquartile range exposure differences, all p < 0.01). Higher rates of allergology and ophthalmology visits were found for participants exposed to higher pollutants' concentrations. When considering the 4-km buffer around the industries, associations with respiratory hospitalizations became significant, and associations with ER pneumology admissions, allergology and ophthalmology visits became stronger. Formaldehyde was not associated with the outcomes considered. ConclusionUsing administrative indicators of health effects a priori attributable to air pollution, we documented the adverse impact of long-term air pollution exposure in residential areas close to the largest chipboard industries in Italy. These findings, combined with evidence from previous studies, call for an action to improve air quality through preventive measures especially targeting emissions related to the industrial activities.

Pollution characteristics and sources of carbonyl compounds in a typical city of Fenwei Plain, Linfen, in summer

Field measurements of atmospheric carbonyl compounds (carbonyls) and essential precursors of O3 were carried out in the urban area of Linfen City (Linfen) where serious O3 pollution has occurred in recent years due to its unique terrain. Carbonyls were sampled using an automatic carbonyl sampler in August 2019 to determine their pollution characteristics and sources. An average concentration of ten carbonyls was 27 ± 5.7 μg m−3 detected using an HPLC-UV system. The concentrations of most detected carbonyls in August were significantly higher than those in the winter months in China. Acetone, formaldehyde and acetaldehyde were the most abundant species, accounting for 73% of all detected carbonyls. Formaldehyde, acetaldehyde, and methacrolein (MACR) were the most significant contributors to OH• reactivity and ozone generation, indicating that these three carbonyls were the key species influencing the production of O3. The concentrations of formaldehyde, acetaldehyde, and MACR showed similar diurnal variations on most days, with high values during the daytime reaching a peak at 10:00. However, the concentrations of the latter two species varied less than that of formaldehyde during the day. The acetone concentration generally increased continuously from morning to night, with the maximum value around 22:00. The C1/C2 ratio in summer was higher than that in winter. These results indicated that the carbonyls in Linfen were not only affected by anthropogenic sources such as vehicle exhaust but also by secondary photochemical production. The results of formaldehyde source apportionment showed that the contributions of background, primary, and secondary sources to the observed formaldehyde concentration were 27.6%, 36.6%, and 35.8%, respectively. Additionally, this study revealed for the first time that the vertical transport of air masses containing high concentrations of O3 and NO3 radicals above the boundary layer could increase the secondary generation of formaldehyde at night in summer.

Kinetic and mechanistic insights into the roles of protonated morpholine species and weak acidic environment in methylacrolein production catalyzed by morpholine/acid

Synthesis of methylacrolein (MAL) from formaldehyde and propanal via Mannich reaction receives significant attention considering the gradual depletion of petroleum resource. Herein, series of morpholine/acid catalyst with different acid type and molar ratio were prepared to catalyze the propanal-formaldehyde reactions for MAL production. The catalytic performance of morpholine/acid was significantly affected by the morpholine/acid ratio, acid type, and initial pH value of reactant mixture. While the addition sequence of reactants and formaldehyde source would influence the yield and selectivity of MAL. As a result, the propanal conversion and MAL yield could reach 99.8 % and 89.7 % with catalysis of morpholine/acetic acid having the molar ratio of 1/3 under weak acidic environment (pH = 5.30) at 50 °C. It was revealed that the protonation of morpholine under weak acidic environment could effectively inhibit the deactivation of morpholine/acetic acid catalyst and promote the production of MAL, however, both basic and strong acidic environment would suppress the formation of MAL. Mechanistic DFT calculations also indicated the protonated morpholine species could not only interact with formaldehyde in the form of morpholine but also act as proton donor. The kinetic studies showed that the formation rate of MAL was first-order dependent on the concentrations of both propanal and formaldehyde with the activation barrier of 30.1 kJ/mol. Undesirably, the optimal morpholine/acetic acid catalyst would be gradually deactivated due to the side reactions of morpholine with formaldehyde, propanal and MAL.

Experiments and a generalized model of the chemical equilibrium of transacetalization and oligomerization of poly(oxymethylene) dialkyl ethers

Poly(oxymethylene) dialkyl ethers (OAE) are oxygenated oligomers that feature favorable physical properties like emission-reducing potential when used as fuels in combustion engines. This work presents a generalized model to describe the chemical equilibrium of water-free mixtures containing OAE, with various terminating alkyl groups and chain lengths, and 1,3,5-trioxane as anhydrous formaldehyde source. The entirely predictive model is based on a generalized equilibrium constant for the formaldehyde oligomerization and statistical considerations. Reaction experiments with various feed compositions are performed at different temperatures and samples are analyzed by NMR spectroscopy. OAE with chain lengths n⩽5 are quantified. The model performs very well when compared to the experimental results of the present work and is thus able to fully describe the chemical equilibrium in mixtures containing OAE and a formaldehyde source. The presented model serves as reliable base for further extensions regarding more complex alkyl groups and systems containing water and alcohols.

Formaldehyde Release From Eyelash Glues: Analysis Using the Chromotropic Acid Method.

Popularity of eyelash enhancements has increased dramatically. Eyelash enhancements are available as an over-the-counter consumer product with glue included and as a professional product where proprietary glues are typically used. Both types of eyelash extension glues may release formaldehyde despite not being declared as an ingredient. Although formaldehyde is a carcinogen and may cause allergic contact dermatitis, few studies have assessed its presence in eyelash glues. The aim of the study was to evaluate professional and consumer eyelash glues for the presence of formaldehyde using the chromotropic acid method (CAM). A total of 37 eyelash glues were evaluated: 17 consumer eyelash glues (2 of which declared formaldehyde) and 20 professional eyelash glues (none of which declared formaldehyde) were purchased and analyzed with the CAM of testing. For consumer eyelash glues, the 2 glues that declared formaldehyde were positive on CAM testing as well as 2 glues (13.3% [2/15]) that did not declare formaldehyde. Of the 20 professional eyelash glues, 15 (75.0%) were positive for formaldehyde. Some consumer eyelash glues and most professional eyelash glues released formaldehyde when evaluated with CAM. Patients and clinicians should be aware that both consumer and professional eyelash glues can be sources of formaldehyde.

Source and variability of formaldehyde (HCHO) at northern high latitudes: an integrated satellite, aircraft, and model study

Abstract. Here we use satellite observations of formaldehyde (HCHO) vertical column densities (VCD) from the TROPOspheric Monitoring Instrument (TROPOMI), aircraft measurements, combined with a nested regional chemical transport model (GEOS-Chem at 0.5×0.625∘ resolution), to better understand the variability and sources of summertime HCHO in Alaska. We first evaluate GEOS-Chem with in-situ airborne measurements during the Atmospheric Tomography Mission 1 (ATom-1) aircraft campaign. We show reasonable agreement between observed and modeled HCHO, isoprene, monoterpenes and the sum of methyl vinyl ketone and methacrolein (MVK+MACR) in the continental boundary layer. In particular, HCHO profiles show spatial homogeneity in Alaska, suggesting a minor contribution of biogenic emissions to HCHO VCD. We further examine the TROPOMI HCHO product in Alaska in summer, reprocessed by GEOS-Chem model output for a priori profiles and shape factors. For years with low wildfire activity (e.g., 2018), we find that HCHO VCDs are largely dominated by background HCHO (58 %–71 %), with minor contributions from wildfires (20 %–32 %) and biogenic VOC emissions (8 %–10 %). For years with intense wildfires (e.g., 2019), summertime HCHO VCD is dominated by wildfire emissions (50 %–72 %), with minor contributions from background (22 %–41 %) and biogenic VOCs (6 %–10 %). In particular, the model indicates a major contribution of wildfires from direct emissions of HCHO, instead of secondary production of HCHO from oxidation of larger VOCs. We find that the column contributed by biogenic VOC is often small and below the TROPOMI detection limit, in part due to the slow HCHO production from isoprene oxidation under low NOx conditions. This work highlights challenges for quantifying HCHO and its precursors in remote pristine regions.