Young children’s mouthing activities thought to be among the most important exposure pathways. Unfortunately, mouthing activity studies have only been conducted in a few countries. In the current study, we used videotaping and computer-based translating method to obtain mouthing activity data for 66 children aged 7 to 35 months old in Taiwan. The median indoor hand-to-mouth and object-to-mouth frequencies were 8.91 and 11.39 contacts h−1, respectively. The median indoor hand-to-mouth and object-to-mouth hourly contact durations were 0.34 and 0.46 min h−1, respectively. The indoor object-to-mouth activities were significantly and negatively correlated with age. Children aged 12 to <24 months in the current study had lower indoor hand-to-mouth and object-to-mouth frequencies than children of same age group in the United States. We also found that indoor mouthing duration with pacifier was significantly and negatively correlated with indoor mouthing duration with other non-dietary objects. The results of the current study indicate that the mouthing behaviors might be different between different countries or populations with different ethnic or lifestyle characteristics. We conclude that using hand-to-mouth frequency values from the current literature may not be most reliable for estimating non-dietary exposures of young children living in Taiwan or even in other similar Asian countries.

Soil and dust ingestion rates by children are among the most critical exposure factors in determining risks to children from exposures to environmental contaminants in soil and dust. We believe this is the first published soil ingestion study for children in Taiwan using tracer element methodology. In this study, 66 children under 3 years of age were enrolled from Taiwan. Three days of fecal samples and a 24-h duplicate food sample were collected. The soil and household dust samples were also collected from children's homes. Soil ingestion rates were estimated based on silicon (Si) and titanium (Ti). The average soil ingestion rates were 9.6±19.2 mg/day based on Si as a tracer. The estimated soil ingestion rates based on Si did not have statistically significant differences by children's age and gender, although the average soil ingestion rates clearly increased as a function of children's age category. The estimated soil ingestion rates based on Si was significantly and positively correlated with the sum of indoor and outdoor hand-to-mouth frequency rates. The average soil ingestion rates based on Si were generally lower than the results from previous studies for the US children. Ti may not be a suitable tracer for estimating soil ingestion rates in Taiwan because the Ti dioxide is a common additive in food. To the best of our knowledge, this is the first study that investigated the correlations between soil ingestion rates and mouthing behaviors in Taiwan or other parts of Asia. It is also the first study that could compare available soil ingestion data from different countries and/or different cultures. The hand-to-mouth frequency and health habits are important to estimate the soil ingestion exposure for children. The results in this study are particularly important when assessing children's exposure and potential health risk from nearby contaminated soils in Taiwan.

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Non-dietary ingestion is an important exposure pathway for children owing to their frequent hand-to-mouth and object-to-mouth activities involving soil and dust contacts. We used videotaping and the computer-based translating methods to quantify the mouthing activity information for 24 children ages 3 to <6 years old living in Taiwan. We also reviewed the entire mouthing activity data collected during the project to determine the lesser studied information on hand surface areas mouthed by children ages <6 years old. The median indoor hand-to-mouth and object-to-mouth frequencies were found to be 10 and 4.3 contacts/h, respectively. Hand-to-mouth and object-to-mouth contact frequencies used in exposure assessments for children ages 3 to <6 years old in this study were similar to the recommended values reported in United States. Exposure Factors Handbook for comparable age US children. The average fractions of the hand area mouthed for children 6 to <12 months, 1 to <2 years, 2 to <3 years, and 3 to <6 years old were 0.12, 0.12, 0.13, and 0.09, respectively. The fraction of hand area mouthed by children was found to be significantly and negatively correlated with their age. About half of the total hand-to-mouth contact events involved immersion of part of a hand or a finger into the mouth. The findings from this study extend the available mouthing activity information for 3 to <6 years old children and also provide new data for an Asian country, allowing comparison of results with western values collected mostly in the United States.

Household air pollution is one of the leading environmental risk factors for death with particulate matter with an aerodynamic diameter less than or equal to 2.5 μm (PM 2.5 ), a classified human carcinogen, 1 as a major concern. [2][3][4] In particular, Asia accounted for two-thirds of global premature deaths, with 1.64 million in 2017 due to household air pollution, 3,4 while the intensities, frequencies, durations, and contribution of distinct PM 2.5 sources in Asian households have seldom been evaluated. In addition, indoor infiltration of high ambient PM 2.5 levels in Asia 5 affecting Indoor Air Quality (IAQ) exacerbates exposure levels indoors. Characterizing PM 2.5 exposures due to these sources in Asian households is critical for both environmental health research and health advisories to reduce the associated health risks. 6,7 PM 2.5 exposures are usually higher than the ambient levels measured by regulatory monitoring stations. [7][8][9] Distinct sources in Asian households such as cooking and incense burning generate

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The low-cost and easy-to-use nature of rapidly developed PM2.5 sensors provide an opportunity to bring breakthroughs in PM2.5 research to resource-limited countries in Southeast Asia (SEA). This review provides an evaluation of the currently available literature and identifies research priorities in applying low-cost sensors (LCS) in PM2.5 environmental and health research in SEA. The research priority is an outcome of a series of participatory workshops under the umbrella of the International Global Atmospheric Chemistry Project–Monsoon Asia and Oceania Networking Group (IGAC–MANGO). A literature review and research prioritization are conducted with a transdisciplinary perspective of providing useful scientific evidence in assisting authorities in formulating targeted strategies to reduce severe PM2.5 pollution and health risks in this region. The PM2.5 research gaps that could be filled by LCS application are identified in five categories: source evaluation, especially for the distinctive sources in the SEA countries; hot spot investigation; peak exposure assessment; exposure–health evaluation on acute health impacts; and short-term standards. The affordability of LCS, methodology transferability, international collaboration, and stakeholder engagement are keys to success in such transdisciplinary PM2.5 research. Unique contributions to the international science community and challenges with LCS application in PM2.5 research in SEA are also discussed.