Aerosol Sprays Research Articles

AEROSOL TOXICITY: AN AYURVEDA PERSPECTIVE

Many aerosol sprays contain toxic chemicals like xylene and formaldehyde, as well as neurotoxins and carcinogens. Overexposure of such components proves harmful to humans. In recent years due to industrialisation and human activities there is rise in air pollution which results in Aerosol Toxicity.

Designing thermoreversible gels for extended release of mosquito repellent.

Mosquito-borne diseases are responsible for 700 000 deaths annually. Current outdoor protective strategies primarily focus on direct skin application of commercial repellents (i.e., aerosol sprays or topical lotions) which are typically limited to efficacy times of ≤10 hours due to rapid evaporation and dermal absorption. Consequently, frequent reapplication for continuous protection can increase associated health hazards and cause noncompliance. This study utilizes Hansen solubility parameter modeling to design physical gels composed of insect-repelling N,N-diethyl-meta-toluamide (DEET) and modacrylic copolymer poly(acrylonitrile-co-vinyl chloride) (P(AN-VC)). The P(AN-VC)/DEET composites exhibit tunable and reversible sol-gel transition temperatures that can meet the thermomechanical stability demands of the intended application and permit facile transition to commercial melt processing techniques such as injection molding, filament spinning, or film casting. P(AN-VC)/DEET gel films demonstrate mosquito repellency for more than half a year-performing longer than any other known material to date-due to the high reservoir of repellent and its desorption hindrance from the polymer matrix. Therefore, P(AN-VC)/DEET gels hold significant potential for extended protection against mosquitos and other biting arthropods.

Advance Biological warfare Agent and Microbial Forensics

Biological struggle is the intentional use of micro-organisms and toxins to produce sickness and loss of life in humans, farm animals and plants, their attraction in warfare, and to be used in terrorist attacks is attributed to various specific features. Organic weapons (BWs) may be disseminated through aerosol sprays, explosives or food and water contamination. Bws can strike all of sudden with none warning and inflict big mortality and morbidity which could keep for a long duration, such assaults may additionally create excessive stage of panic, environment infection and severe pressures on emergency fitness offerings. Bioterrorism is the usage of bows in terrorism. modern-day issues regarding the use of bows end result from the growing wide variety of countries which might be engaged in the proliferation of such guns and their acquisition by way of terrorist groups. The want of the hour is to broaden bio defence via full worldwide cooperation and to educate the likely target populations approximately precautions and shielding measures to be taken in such assaults.

Comparison of sampling methods for the determination of volatile organic compounds in consumer aerosol sprays

Many studies have evaluated the hazardous substances contained in various household chemical products. However, for aerosol spray products there is currently no international standard sampling method for use in a component analysis. The aim of this study was to develop an appropriate sampling method for the analysis of volatile organic compounds (VOCs) in consumer aerosol sprays. Two different sampling methods, spraying (into a vial) and perforating (and transferring the contents into a vial), were used to evaluate the levels of 16 VOC components in eight different aerosol spray products. All eight products contained trace amounts of hazardous VOCs, and a quantitative analysis showed that, for the same product, VOC concentrations were higher when spraying than when perforating. Using the spraying method, average toluene, ethylbenzene, p-xylene, o-xylene, and styrene concentrations were 1.80-, 2.10- 2.25-, 2.03-fold, and 1.28-fold higher, respectively, than when using the perforating method. The spraying method may provide more realistic estimates of the user's exposure to harmful substances and the associated health risks when using spray products. Of the two representative methods widely used to analyze harmful substances in consumer aerosol sprays, the spraying method is recommended over the perforating method for the analysis of VOCs.

Standard precautions should include 'safe ventilation' to minimise far-afield airborne transmission in health and social care settings.

Standard precautions should include 'safe ventilation' to minimise far-afield airborne transmission in health and social care settings.

Examining Inhalant Use Among Sexual Minority Adults in a National Sample: Drug-Specific Risks or Generalized Risk?

Purpose: The study objective was to compare use of 12 specific inhalants among lesbian, gay, and bisexual (LGB) adults relative to heterosexual adults among a national sample. Methods: Data on 210,392 adults, including 15,007 LGB adults, were from the 2015 to 2019 National Survey on Drug Use and Health. For each inhalant type, logistic regression was used to characterize differences by sexual identity and gender. Unadjusted and demographic adjusted odds ratios are reported. Results: All LGB groups exhibited elevated use of multiple inhalant types (ranging from 5 for gay males to 12 for bisexual females). The largest disparities were for poppers among gay and bisexual males. Gay and bisexual males initiated use at older ages. Conclusion: Observed disparities among LGB adults included inhalants used in a sexual or club context (e.g., poppers) as well as types with particularly elevated fatality risk (e.g., butane, propane, aerosol sprays, and nitrous oxide).

Wound healing activity of topical herbal aerosol sprays on diabetic and Varicose Ulcers: A randomized, controlled, open labelled, multi-centric clinical trial

BackgroundPanchavalkala Kwatha and Jatyadi Taila are recommended for cleaning and healing of non-healing ulcers such as Diabetic Foot Ulcer (DFU) and Varicose Ulcers (VU). ObjectivesInnovative topical aerosol sprays viz. Panchavalkala Kwatha Aerosol Spray (PKS) and Jatyadi Taila (Healz) Aerosol Spray (JTS) were evaluated for healing in DFU & VU against conventional treatment. Materials & methodsAfter obtaining approval from Ethics Commitees & informed consent, 53 patients were randomized in two study groups. In one group, ulcer cleaning was done with PKS and then JTS was used for dressing while in other group, cleaning was done with Hydrogen peroxide and/or Hypochlorite followed by dressing with 10% Povidone iodine. Ulcer examination was done from baseline to every 7th day by Bates Jensen ulcer assessment tool, digital photographs and photographic ulcer assessment tool. Comparison of categorical variables was done using t-test. ResultsThe dual action of PKS and JTS exhibited potentially comparable effect to the conventional treatment. ConclusionPKS and JTS were found to be effective, comfortable, hygenic and acceptable in management of chronic ulcers.

Determination of the water-soluble polymer poly(N-vinylcaprolactam) in wastewater effluents by continuous-flow off-line pyrolysis-GC/MS

High production rates and wide areas of application of water-soluble polymers indicate their potential occurrence in wastewater. Poly(N-vinylcaprolactam) (PNVCL) is such a water-soluble and poorly biodegradable polymer with non-ionic, non-sticky, non-toxic and thermosensitive properties. Its field of applications covers being a constituent in aerosol sprays, pump sprays, and lotions as well as its usage as flocculant in wastewater treatment plants. However, although discharged into sewage treatment plants at high amounts, analytical methods for determining water soluble polymers, in particular PNVCL, in environmental samples are still missing. Therefore, this study aims at developing an efficient analytical method for detecting trace levels of poly(N-vinylcaprolactam) in wastewaters by applying continuous-flow off-line Py-GC/MS for the first time. The approach was based on the identification of specific off-line pyrolysis products (ε-caprolactam, N-vinylcaprolactam) that haven been used in the following for a calibration process that allowed a quantitative determination. An evaluation including specificity, linearity, sensitivity and reproducibility characterized this approach as very suitable for detection of this polymer in complex environmental matrices such as wastewaters. Finally, the transferability has been checked by analyzing a real wastewater from a sewage treatment plant effluent. Here limitations especially due to matrix effects are lowering the sensitivity of the pyrolysis-based method. Nevertheless, a contamination with approx. 70 µg/L of poly(N-vinylcaprolactam) was determined pointing to a huge emission of PNVCL into the aquatic environment and a general high environmental relevance of this synthetic polymer. Noteworthy, this is the first report on the occurrence of poly(N-vinylcaprolactam) in environmental samples.

Effect of household air pollutants on the composition of exhaled breath characterized by solid-phase microextraction and needle-trap devices.

Exposure to household air pollutants is becoming a serious environmental health risk. Various methods can be applied to assess humans' exposure status to indoor pollutants, with breath monitoring being among the best options. Breath sampling is fast and non-invasive, and contains compounds that can be used as markers for evaluating exposure length and estimating internal concentrations of pollutants. However, the distribution of compounds between gas and droplets in breath samples represents one of the key challenges associated with this analytical method. In this work, a needle-trap device (NTD) was prepared by packing the needle with a porous filter, divinyl benzene, and Carboxen to enable the exhaustive capture of both droplet-bound and gaseous components. Furthermore, fiber-based solid-phase microextraction (SPME) was also applied to extract compounds from only the gas phase to distinguish this portion of analytes from the total concentration in the sample. Dynamic, real-time breath sampling was enabled via a new sampling tube equipped with 2 one-way valves, which was specially designed for this work. Both methods provided satisfactory reproducibility, repeatability, and sensitivity, with detection limits as low as 0.05ngmL-1. To investigate the real-world applicability of the proposed devices, breath samples were obtained from volunteers who had been exposed to candle and incense smoke and aerosol sprays, or had smoked cannabis. The results revealed the high concentration of organic air pollutants in inhaled air (maximum of 215ngmL-1) and exhaled breath (maximum of 14.4ngmL-1) and a correlation between the components in inhaled air and exhaled breath. Significantly, the findings further revealed that the developed NTD has enhanced breath-sample determinations, especially for polar compounds, which tend to remain trapped in breath droplets.

Independent Sun Care Product Screening for Benzene Contamination.

Independent Sun Care Product Screening for Benzene Contamination.

Assessing health-seeking behaviour and malaria prevention practices among communities in four districts of the Volta Region of Ghana

BackgroundMalaria is a preventable disease that causes huge morbidity and mortality in malaria-endemic areas, especially among children and pregnant women. The malaria control programme focuses on the prevention of mosquito bites using insecticide-treated nets (ITNs) and mosquito aerosol sprays and coils, as well as prevention of severe disease among those infected through prompt and adequate treatment. The success of the malaria control programme in Ghana is dependent on the malaria prevention practices of people in the community. Therefore, this study evaluated the malaria prevention practices of participants in four districts of the Volta Region of Ghana.MethodsThis was a cross-sectional study conducted in Ketu South, Nkwanta South, Hohoe Municipality and Ho West districts of the Volta Region of Ghana. Questionnaire were administered to adults who consented to each household visited. Questions were asked on the socio-demographics and malaria prevention practices of the households. Data analysis was done using SPSS version 23 with frequency distribution done for all the variables. Pearson chi-square was used to determine the significant association between socio-demographics and malaria prevention practices, and Multivariate nominal logistic regression analysis was used to model the relationship between dichotomous dependent variables (ITN ownership and usage) and independent variables.ResultsOut of the 2493 participants; 2234 (89.6%) owned ITN and 1528 (68.4%) used ITN a night before this study, 768 (30.8%) used mosquito aerosol spray and 368 (15%) used mosquito coil. More females significantly owned ITN than males (1293, 92.4%, p ≤ 0.001). Participants from Ketu South had 1.5 times higher odds of owning an ITN compared to Ho West whose odds are not different from Nkwanta South or Hohoe (AOR, 1.56 [95% 1.09–2.22]; p = 0.01). In terms of ITN usage, participants in Nkwanta South were less likely to use ITN compared to the other districts; AOR, 0.434 [95% CI 0.31–0.62, p < 0.001]. Also, of the 668 participants that had a fever within the past 3 days, 268 (40.1%) visited a patent medicine store and 156 (23.4%) visited health facilities.ConclusionThere is high ownership of ITNs, but relatively low utilization among the community members. Education on malaria prevention practices should be intensified and continuous among the population of the Volta Region to ensure the success of malaria control in the region.

Effects of pressure decay on Non-Methane Volatile Organic Compounds (NMVOC) species distribution in domestic aerosol sprays with LPG propellants

Conventional aerosols sprays contain different Volatile Organic Compounds (VOC). These organic compounds have different properties and can have detrimental impact on air quality. This study investigated the spray performance and variation of the types of Non-Methane VOCs (NMVOCs) expelled over the life of pressurised aerosol spray can. Three types of aerosol sprays – hair sprays, deodorants, and antiperspirants were selected from the solvent-based cosmetic products. Mass Ratio (MR) of solvent (ethanol) to propellant (LPG) for all the products was analysed at pressure decay sequences of 4, 3, 2, and 1.5 bar. It was found that the MR in hair sprays expelled was significantly higher than that of antiperspirants and body sprays by 53% and 54% respectively at 4 bar. As the pressure depleted, however, the antiperspirant and body sprays’ MR decreased while that of the hair spray increased. At the lower pressures (2 bar), the hair spray had the highest MR and antiperspirant had the lowest. This finding is important in evaluating the performance of the delivery pathways of aerosol spray products and will provide insight into the effective design of atomisers with alternative “green” propellants like compressed air replacing LPG as the primary propellant in spray products.

Efficacy of five commercial household insecticide aerosol sprays against pyrethroid resistant Aedes aegypti and Culex quinquefasciatus mosquitoes in Thailand

Commercial insecticide aerosol sprays are widely used in households for controlling Aedes aegypti and Culex quinquefasciatus, the primary vectors of dengue virus and filarial worm, respectively. In Thailand, however, both mosquitoes are resistant to pyrethroids conferred by knockdown resistance (kdr) mutations, V1016G and F1534C in Ae. aegypti and L1014F in Cx. quinquefasciatus. This study evaluated the efficacy of five sprays (coded as AS1-AS5) with different formulations of pyrethroids against wild mosquitoes by using a cage bioassay in a furnished bedroom of a house. Five cages containing wild mosquitoes and five cages containing a pyrethroid susceptible strain of Ae. aegypti (25 females each), as a bio-indicator, were allocated in the room and spraying was operated for 15 s. Survivors and dead mosquitoes were genotyped individually for the kdr mutations using allele-specific PCR methods. Both mosquito species showed a high resistance to permethrin and deltamethrin with 12.5–58.0% mortality rates. For controlling Ae. aegypti, the spray AS4 showed the highest efficacy (mortality rates 76.0–100.0%, mean 95.2%), followed by AS2 (73.0–100.0%, mean 93.8%). For controlling Cx. quinquefasciatus, the best result was obtained from AS4 (66.0–98.0% mortality, mean 89.8%), followed by AS2 (73.0–97.0%, mean 84.5%). The sprays (AS4 and AS2) containing both type I and type II pyrethroids were more effective than those containing only type I pyrethroids or pyrethrum with the synergist piperonyl butoxide. The mutant G1016 and F1014 allele frequencies were significantly higher in the survivor groups than the dead groups of Ae. aegypti and Cx. quinquefasciatus, respectively, (P < 0.05). The efficacy of the sprays varied depending on the mosquito species, formulations, nozzles and locations of caged mosquitoes. The V1016G and L1014F mutations are associated with the reduced efficacy of sprays used in households for controlling resistant Ae. aegypti and Cx. quinquefasciatus mosquitoes, respectively.

A retail audit of mosquito control products in Busia County, western Kenya

BackgroundApproximately 70% of Kenya’s population is at risk for malaria. The core vector control methods in Kenya are insecticide-treated mosquito nets (ITNs) and indoor residual spraying, with supplementary larval source management. In 2015, 21% of ITNs were accessed through the private retail sector. Despite the private sector role in supplying mosquito control products (MCPs), there is little evidence on the availability, sales trends, and consumer preferences for MCPs other than ITNs. This study, a component of a larger research programme focused on evaluating a spatial repellent intervention class for mosquito-borne disease control, addressed this evidence gap on the role of the private sector in supplying MCPs.MethodsA cross-sectional survey was deployed in a range of retail outlets in Busia County to characterize MCP availability, sales trends, and distribution channels. The questionnaire included 32 closed-ended and four open-ended questions with short answer responses. Descriptive analysis of frequency counts and percentages was carried out to glean insights about commercially available MCPs and the weighted average rank was used to determine consumer preferences for MCPs. Open-ended data was analysed thematically.ResultsRetail outlets that stocked MCPs commonly stocked mosquito coils (73.0%), topical repellents (38.1%), aerosol insecticide sprays (23.8%) and ITNs (14.3%). Overall, retailers reported the profits from selling MCPs were adequate and they overwhelmingly planned to continue stocking the products. Of respondents who stocked MCPs, 96.8% responded that sales increased during long rains and 36.5% that sales also surged during short rains. ITNs and baby-size nets were often delivered by the wholesaler. Retailers of aerosol sprays, mosquito coils, and topical repellents either collected stock from the wholesaler or products were delivered to them. Other commercially available MCPs included insecticide incense sticks, electric mosquito strikers, insecticide soaps, electrically heated insecticide mats, and electric insecticide emanators, indicating a well-established market.ConclusionsThe wide range of MCPs in local retail outlets within the study area suggests the need and demand for mosquito control tools, in addition to ITNs, that are affordable, easy to use and effective. The presence of a wide range of MCPs, is a promising sign for the introduction of a spatial repellent intervention class of products that meets consumer needs and preferences.

A Comparison of Beclomethasone Aqueous Spray and Aerosol Delivery System in Nasal Polyps: A Randomized Control Trial.

Background:Considering the effect of beclomethasone on allergic rhinitis or nasal polyps, it has been attempted to find the best method of using this drug to have the maximum effect and increase the patients' satisfaction. Therefore, the aim of this study was to compare the efficacy of beclomethasone aerosol and aqueous nasal sprays in the patients with nasal polyps.Materials and Methods:This double-blind randomized clinical trial was conducted on 60 patients with nasal polyps. The patients were divided into two groups. The first group (beclomethasone dipropionate aqueous [BD-AQ] group) was treated with daily two puffs of beclomethasone aqueous nasal spray 50 μg in each nostril, and the second group (beclomethasone dipropionate aerosol [BD-A] group) was treated with two puffs of aerosol beclomethasone 50 μg in each nostril daily for 6 months. At the beginning of the study, the sino-nasal outcome test-22 (SNOT-22) and Lund-Mackay scores were recorded after the evaluation of disease status and the severity of symptoms.Results:The results of this study demonstrated that the mean changes in Lund-Mackay and SNOT-22 scores (83 ± 6.30 and 4.25 ± 31.60, respectively) in the BD-A group were significantly higher than the BD-AQ group (2.01 ± 3.87and 9.83 ± 24.13, respectively) (P < 0.05), but there was no significant difference in the patients' satisfaction between the two groups (P > 0.05).Conclusion:According to the results of this study, patients with nasal polyps showed a significant improvement following both the interventions, but the disease severity in the BD-A group was significantly higher than the BD-AQ group based on the mean values of Lund-Mackay score.

CARBON COMPOUNDS: Pollution Aspects

Carbon is one of the major elements by which organic compounds cannot be imagined. Its compounds are very useful in human life as well as for nature. For example, carbon dioxide is used during photosynthesis in plants and CFCs is used in manufacturing of aerosol sprays and as refrigerants. In contrast, serious harmful effects are seen with over exposure or with increasing in level of its compounds. Use of carbon compounds awareness is necessary for its use in different purposes. Carbon monoxide and carbon dioxide released by the complete combustion of fossils and by automobile exhaust causes carbon pollution along with other various causes. Reuse and recycling of carbon compounds minimizes its pollution. Carboxy hemoglobin formed by combination of carbon monoxide with red blood cell is also more fatal. As we know, different gases formed due to the combination of carbon with other elements causes various changes like climate change, destruction of heritage goods (acid rain), different human risk, flooding etc. So, pollution of carbon should be managed before it causes any huge harmful effects. Finally, carbon related pollution leads to global warming, greenhouse effects, ozone layer depletion, ocean acidification, acid rain, climate change and also fatal to human beings.

Measurements and analysis of non-methane VOC (NMVOC) emissions from major domestic aerosol sprays at “source”

Non-Methane Volatile Organic Compounds (NMVOCs) from domestic aerosol sprays are emerging pollutants and have substantial negative effects on human health and the environment. This study, for the first time, carried out quantification of the NMVOC emissions from off-the-shelf domestic aerosol sprays, at “source” in the UK. These aerosol sprays contain harmful organic compounds as propellants and products. The results showed that the cosmetic category (i.e. body sprays) have higher concentrations of NMVOCs with 93.7 wt% per can compared to households (i.e. air fresheners) with 62 wt%. Also, water-based products showed less NMVOCs in all analyses compared to solvent-based formulations. Direct replacement of Liquefied Petroleum Gas (LPG) propellants from conventional products with ‘clean air’ (i.e. nitrogen) showed the potential emission reduction of 50%. Hair spray products, however, have the highest ozone forming potential with about 105.1 g of Ozone per litre of the product compared to other domestic aerosol sprays. The level of global warming contribution of the selected aerosol sprays in the UK was measured to be 129.8 ktCO2e in 2018 and globally, this can be projected to be 3154.6 ktCO2e in 2020. Furthermore, NMVOC emissions contribution from the domestic aerosol sprays in the UK was measured as 61.2 kt in 2018 based on annual consumption of 520 million cans. Globally this can equate to 1437.6 kt based on the projected usage of 17.5 billion cans. Therefore, it is vital to expedite replacing LPG propellant with nitrogen in a drive for a ‘near-zero’ emission in aerosol industry. The results presented in this study can also be used to steer policy makers to the potentially brewing danger from an otherwise passive emission source.

The Alarming Community Concern on Household Insecticide Exposure and Usage

The utilization of insecticide in a household environment is a necessity especially for those living in the tropical country such as Malaysia. Tropical climate with high humidity and urbanization lead to pests breeding problem hence contributing to the spread of vector diseases such as dengue. Household insecticide such as aerosol sprays, coils and mats are made from a combination of chemicals from type 1 pyrethroid group which are recognized as safe and have minimal toxic effects on human. However, there have been cases of accidental and intentional insecticide poisoning which demonstrates the lack of studies on factors of knowledge, attitude and practice of insecticide usage, the exposure as well as clinical presentation since the symptoms are similar to other compounds which may lead to misdiagnosis. These insecticide chemicals do not only exert toxic effects to pest but to human too due to its highly toxic characteristic which causes diseases such as asthma, cancer, and other diseases following short or long-term exposure to the chemicals. As a result, there is a growing community health concern regarding the uncertainty and risk of insecticide exposure to human. Thus, the risk assessment of community’s knowledge, attitude and practice regarding the insecticide are essential in aiding towards the development of improving insecticide profile, safer insecticide handling and exploration of insecticide alternative. This will result in better insecticide awareness, as well as minimize the insecticide risk exposure and its adverse health effects to the community.

Prospective Evaluation of Intensity of Symptoms, Therapeutic Procedures and Treatment in Palliative Care Patients in Nursing Homes.

The aim of the study is to evaluate the intensity of symptoms, and any treatment and therapeutic procedures received by advanced chronic patients in nursing homes. A multi-centre prospective study was conducted in six nursing homes for five months. A nurse trainer selected palliative care patients from whom the sample was randomly selected for inclusion. The Edmonton Symptoms Assessment Scale, therapeutic procedures, and treatment were evaluated. Parametric and non-parametric tests were used to evaluate month-to-month differences and differences between those who died and those who did not. A total of 107 residents were evaluated. At the end of the follow-up, 39 had (34.6%) died. All symptoms (p < 0.050) increased in intensity in the last week of life. Symptoms were more intense in those who had died at follow-up (p < 0.05). The use of aerosol sprays (p = 0.008), oxygen therapy (p < 0.001), opioids (p < 0.001), antibiotics (p = 0.004), and bronchodilators (p = 0.003) increased in the last week of life. Peripheral venous catheters (p = 0.022), corticoids (p = 0.007), antiemetics (p < 0.001), and antidepressants (p < 0.05) were used more in the patients who died. In conclusion, the use of therapeutic procedures (such as urinary catheters, peripheral venous catheter placement, and enteral feeding) and drugs (such as antibiotics, anxiolytics, and new antidepressant prescriptions) should be carefully considered in this clinical setting.

Linking internal dosimetries of the propyl metabolic series in rats and humans using physiologically based pharmacokinetic (PBPK) modeling

The metabolic series approach has successfully linked internal dosimetries of metabolically related compounds reducing cost and time for chemical risk assessments. Here, we developed a physiologically based pharmacokinetic (PBPK) model in rats and humans for the propyl metabolic series including propyl acetate, 1-propanol, propionaldehyde, and propionic acid. Manufacturers use these compounds as organic solvents and intermediates during chemical synthesis. Public exposures can occur through using consumer products containing propyl compounds like cosmetics, aerosol sprays, or foods, and occupational exposures can occur at manufacturing facilities. To develop the PBPK model, we measured in vitro metabolism of propyl acetate in blood and liver S9 fractions. We measured concentrations of propyl compounds in blood following intravenous (iv) infusion of 13C-propanol or 13C-propionic acid and closed chamber inhalation exposures to propyl acetate or propanol in rats. Using these studies and other published data, we modified an existing PBPK model for the butyl metabolic series to simulate time course concentrations of propyl compounds in rats and humans. Consistent with measured in vitro and in vivo data, the optimized propyl series model predicts rapid clearance of propyl acetate, higher concentrations of propanol in blood from propyl acetate inhalation compared to propanol inhalation in rats but not in humans, and low concentrations of propionic acid in blood from exposures to propyl acetate or propanol. Regulators can use this model as a tool for propyl compound risk assessment by linking internal dosimetries under various exposure scenarios.