An Assessment of Annual Mortality Attributable to Ambient PM2.5 in Bangkok, Thailand

Incidence of grass and weed sensitization in Bangkok, Thailand: a clinical study

Background

Allergic rhinitis (AR) is a prevalent public health concern globally, significantly impacting quality of life. In Thailand, the prevalence of AR is rising, with grass and weed pollen identified as primary outdoor triggers.

Objectives

This study aimed to (1) assess patterns of pollen sensitization in Thai AR patients and (2) investigate correlations between demographics/clinical data and SPT results.

Methods

A total of 121 individuals aged ≥18 years with clinically diagnosed AR were recruited. Skin prick testing (SPT) was performed using a panel of commonly encountered tropical grass and weed pollen extracts. SPT wheal sizes and clinical symptom scores were recorded. Correlations between SPT outcomes and symptom scores were analyzed.

Results

Among the participants, 104 (85.95%) exhibited positive SPT reactions to at least one pollen type. Nutsedge (76/121), para grass (57/121), and Bermuda grass (48/121) were the most frequently identified allergens. Hurricane grass elicited the strongest reaction, evidenced by the highest average wheal size (6.2 mm). Poly-sensitization was observed in 77 (63.6%) of the SPT-positive individuals, with most cases involving two different pollen extracts (35/77). Notably, AR severity positively correlated with both average wheal size and the number of positive SPT tests.

Conclusion

This study highlights nutsedge, para grass, and Bermuda grass as major allergenic pollen sources for Thai AR patients. Including nutsedge, hurricane grass, and careless weed in clinical SPT panels is recommended for improved diagnostic accuracy. Additionally, the positive correlation between AR severity and pollen reaction strength emphasizes the importance of implementing patient education and avoidance strategies.

Estimation of health-related and economic impacts of PM2.5 in Arak, Iran, using BenMAP-CE

Ambient air quality is one of the most critical threats to human health. In this study, the health and economic benefits of reducing PM2.5 were estimated in the city of Arak during the period of 2017-2019. The concentration data were obtained from the Environmental Protection Organization of Central Province, while the demographic data were obtained from the website of the Iran Statistics Center. The number of premature deaths from all causes, ischemic heart disease, chronic obstructive pulmonary disease, and lung cancer, attributable to PM2.5 pollution was estimated using the Environmental Benefits Mapping and Analysis Program-Comprehensive Version (BenMAP_CE) to limit the guidelines of the World Health Organization. The results showed that improving air quality in 2017, 2018, and 2019 in Arak could prevent the deaths of 729, 654, and 460 people, respectively. The number of years of life lost (YLL) in 2017, 2018, and 2019 was 11383, 10362, and 7260 years, respectively. The total annual economic benefits of reducing the PM2.5 concentration in Arak under the proposed scenarios in 2017, 2018, and 2019 were estimated to be 309,225,507, 262,868,727, and 182,224,053 USD, respectively, using the statistical life method (VSL). Based on the results of this study, there are significant health and economic benefits to reducing PM2.5 concentrations in Arak City. Therefore, planning and adopting control policies to reduce air pollution in this city are necessary.

Estimation of health risk and economic loss attributable to PM2.5 and O3 pollution in Jilin Province, China

Ambient pollutants, particularly fine particulate matter (PM2.5) and ozone (O3), pose significant risks to both public health and economic development. In recent years, PM2.5 concentration in China has decreased significantly, whereas that of O3 has increased rapidly, leading to considerable health risks. In this study, a generalized additive model was employed to establish the relationship of PM2.5 and O3 exposure with non-accidental mortality across 17 districts and counties in Jilin Province, China, over 2015-2016. The health burden and economic losses attributable to PM2.5 and O3 were assessed using high-resolution satellite and population data. According to the results, per 10 µg/m3 increase in PM2.5 and O3 concentrations related to an overall relative risk (95% confidence interval) of 1.004 (1.001-1.007) and 1.009 (1.005-1.012), respectively. In general, the spatial distribution of mortality and economic losses was uneven. Throughout the study period, a total of 23,051.274 mortalities and 27,825.015 million Chinese Yuan (CNY) in economic losses were attributed to O3 exposure, which considerably surpassing the 5,450.716 mortalities and 6,553,780 million CNY in economic losses attributed to PM2.5 exposure. The O3-related health risks and economic losses increased by 3.75% and 9.3% from 2015 to 2016, while those linked to PM2.5 decreased by 23.33% and 18.7%. Sensitivity analysis results indicated that changes in pollutant concentrations were the major factors affecting mortality rather than baseline mortality and population.

Estimation of premature death attributed to short- and long-term PM2.5 exposure in Thailand

Particulate matter with a diameter of less than 2.5 microns (PM2.5) has been identified as a global health concern in recent decades. Indeed, PM2.5 exposure causes detrimental health problems in the general population. Estimating the short- and long-term health impacts of PM2.5 exposure should help to shape public health policy concerning air pollution. Hence, this study sought to estimate the rate of premature death attributable to PM2.5 exposure among the Thai population if the PM2.5 concentration met the applied counterfactual factor. The PM2.5 concentration, population numbers, and numbers of health incidences were collected from secondary data sources in 2019. A health impact analysis was performed using AirQ+ software to estimate the incidences of premature deaths attributable to PM2.5 exposure. More specifically, the analysis provided the estimated proportion of attributable cases and the rate of premature death per 100,000 population aged ≥ 30 years. The annual average PM2.5 concentration in Thailand was found to be 24.15 µg per cubic meter (μg/m3) in 2019, while the natural mortality rate was around 1,107 per 100,000 population nationwide. With regard to short-term PM2.5 exposure, it was determined that 8 premature deaths per 100,000 population could be prevented if the PM2.5 concentration met the World Health Organization (WHO) short-term gold standard of 15 μg/m3. Moreover, 159 premature deaths per 100,000 population could be avoided if the PM2.5 concentration met the WHO's long-term gold standard of 5 μg/m3. This estimation of premature deaths due to the short- and long-term impacts of PM2.5 exposure can support policymakers and stakeholders in creating a roadmap to combating the adverse impacts of PM2.5 exposure and protect the health of the Thai population.

What Sustains Mask-Wearing Behavior among Elders in a Rural Community in the Post-COVID-19 Era: An Exploratory Mixed-Methods Study

The current study investigates the factors influencing face-mask-wearing practices among elderly individuals in rural Thailand. A mixed-methods approach was employed, involving qualitative interviews with 15 elderly participants and a subsequent survey of 201 elders. Seven subthemes were identified, including the perceived benefits of mask-wearing, the perceived threat of COVID-19, mask-wearing enhancing attractiveness and self-confidence, social norms, misconceptions about COVID-19 prevention tools, perceived barriers to mask-wearing, and resources to afford face masks. The developed themes, codes, and quotes were utilized for creating a questionnaire. The survey revealed the adherence of 81.1% of the participants to mask-wearing. Structural equation modeling (SEM) analysis demonstrated that motivation, comprising (1) the perceived threat of COVID-19, (2) alternative threats aside from COVID-19, and (3) the perceived benefits of a face mask strongly affected mask-wearing practices (β = 0.68, p < 0.001) and the willingness to wear a face mask (β = 0.61, p < 0.001). Social norms had a negative direct effect on the perceived barrier (β = -0.48, p < 0.001) and a positive direct effect on mask-wearing practices (β = 0.25, p = 0.001). This study highlights that motivation and social norms play pivotal roles in sustaining mask-wearing behavior among rural elderly populations. Encouraging local cooperative actions through community rules could initiate behavioral changes within the community. These findings contribute to the understanding of factors influencing mask-wearing and provide insights into designing effective interventions to promote mask-wearing among elderly individuals in rural areas.

Health Impact Assessment of Short-Term Exposure to Particulate Matter (PM10) in Northern Thailand

In northern Thailand, in recent decades, particulate pollution from the burning of biomass has become a serious issue with toxicological implications for human health, especially during the winter months of January to April. The purpose of this study was to explore short-term exposure to particulate matter (PM₁₀) in northern Thailand. The high PM₁₀ concentration in 2012 was used as a case study. We used the EPA's Benefits Mapping and Analysis Program-Community Edition (BenMAP-CE) for the health impact assessment, along with ground-based measurement data. The annual average observed PM₁₀ concentration was in the range of 43-61 μg/m³, with a maximum observed PM₁₀ concentration of 300 μg/m³ in March. We then assessed the impacts of PM₁₀ exposure in northern Thailand. When the PM₁₀ concentration was reduced to 120 μg/m³, the undesirable effects on respiratory mortality decreased by 5%-11%. When the concentration of PM₁₀ was reduced to 45 μg/m³, the deleterious effects on respiratory mortality decreased by 11-30%. In conclusion, adherence to the WHO-AQG, particularly for PM₁₀ (45 μg/m³), tends to result in considerable reductions in respiratory disease mortality in northern Thailand.

Assessment of health burden due to the emissions of fine particulate matter from motor vehicles: A case of Nakhon Ratchasima province, Thailand

Air pollution, owing to the ever-increasing transport vehicle fleet, and adverse health effects are increasing in provinces of Thailand. The study estimated that the vehicle fleet size of Nakhon Ratchasima (NR) province of Thailand will grow to 2 million vehicles by 2030, which was 1.36 million in 2021. In NR, the PM2.5 and PM10 concentrations already surpassed both WHO and NAAQS guidelines in 2019-2021. Using Pollution Control Department (PCD) approved Tier I and II Methodology of EMEP/EEA, this research estimated that the total tailpipe emission load will be 1039 tons of PM2.5, 16,630 tons of NO₂, 20,623 tons of CO, 195 tons NH₃, and 249 tons of SO₂ in NR during 2030. The emission load will increase to 1752 tons of PM2.5, 21,126 tons of NO2, 25,559 tons of CO, 361 tons of NH3 and 9344 tons of SO₂ during 2030 if upstream emissions are considered. This study has developed five control scenarios in line with the directives of PCD to mitigate the adverse health from vehicle-led air pollution in NR and implementation during 2024-2030. According to the study, different control scenarios to be implemented during 2024-2030, will be able to keep the fleet size of vehicles in the NR under control. The results show that the control scenarios will keep the annual tailpipe emission of PM2.5 at 604 tons in 2030, a 42 % reduction over the 2030 Business-As-Usual scenario (BAU). The health damage in the range of 6941 to 11,625 disability-adjusted life years (DALYs) under the 2030 BAU scenario in NR due to tailpipe and upstream emissions can be reduced to 4162-7318 DALYs with the implementation of different control scenarios. The control scenarios will also provide significant economic benefits ranging from 4465 to 6718 million THB during 2024-2030 through reduced DALYs and associated costs.

Particle Number Concentration Measurements on Public Transport in Bangkok, Thailand

Traffic is a major source of particulate pollution in large cities, and particulate matter (PM) level in Bangkok often exceeds the World Health Organisation limits. While PM_2.5 and PM₁₀ are both measured in Bangkok regularly, the sub-micron range of PM, of specific interest in regard to possible adverse health effects, is very limited. In the study, particle number concentration (PNC) was measured on public transport in Bangkok. A travel route through Bangkok using the state railway, the mass rapid transport underground system, the Bangkok Mass Transit System (BTS) Skytrain and public buses on the road network, with walking routes between, was taken whilst measuring particle levels with a hand-held concentration particle counter. The route was repeated 19 times covering different seasons during either morning or evening rush hours. The highest particle concentrations were found on the state railway, followed by the bus, the BTS Skytrain and the MRT underground with measured peaks of 350,000, 330,000, 33,000 and 9000 cm^-3, respectively, though particle numbers over 100,000 cm^-3 may be an underestimation due to undercounting in the instrument. Inside each form of public transport, particle numbers would peak when stopping to collect passengers (doors opening) and decay with a half-life between 2 and 3 min. There was a weak correlation between particle concentration on bus, train and BTS and Skytrain with carbon monoxide concentration, as measured at a fixed location in the city.

Temporal, compositional, and functional differences in the microbiome of Bangkok subway air environment

With the growing numbers of the urban population, an increasing number of commuters have relied on subway systems for rapid transportation in daily life. Analyzing the temporal distribution of air microbiomes in subway environments is crucial for the assessment and monitoring of air quality in the subway system, especially with regard to public health. This study employed culture-independent metabarcode sequencing to analyze bacterial diversity and variations in bacterial compositions associated with bioaerosols collected from a subway station in Bangkok over a four-month period. The bacteria obtained were found to consist primarily of Proteobacteria, Firmicutes, and Actinobacteria, with variations at the family, genus, and species levels among samples obtained in different months. The vast majority of these bacteria are most likely derived from outside environments and human body sources. Many of the bacteria found in Bangkok subway station were also identified as "core microorganisms" of subway environments around the world, as suggested by the MetaSUB Consortium. The diversity of bacterial communities was shown to be influenced by several air quality variables, especially ambient temperature and the quantity of particulate matters, which showed positive correlations with several bacterial species such as Acinetobacter lwoffii, Staphylococcus spp., and Moraxella osloensis. In addition, metabolic profiles inferred from metabarcode-derived bacterial diversity showed significant variations across different sampling times and sites and can be used as a starting point to further explore the functional roles of specific groups of bacteria in the subway environment. This study thus introduced the information required for surveillance of microbiological impacts and their contributions to the well-being of subway commuters in Bangkok.

In vivo tracking of toxic diesel particulate matter in mice using radiolabeling and nuclear imaging

Exposure to diesel particulate matter (DPM) is associated with several adverse health effects, including severe respiratory diseases. Quantitative analysis of DPM in vivo can provide important information on the behavior of harmful chemicals, as well as their toxicological impacts in living subjects. This study presents whole-body images and tissue distributions of DPM in animal models, using molecular imaging and radiolabeling techniques. The self-assembly of the ⁸⁹Zr-labeled pyrene analog with a suspension of DPM efficiently produced ⁸⁹Zr-incorporated DPM (⁸⁹Zr-DPM). Positron emission tomography images were obtained for mice exposed to ⁸⁹Zr-DPM via three administration routes: intratracheal, oral, and intravenous injection. DPM was largely distributed in the lungs and only slowly cleared after 7 days in mice exposed via the intratracheal route. In addition, a portion of ⁸⁹Zr-DPM was translocated to other organs, such as the heart, spleen, and liver. Uptake values in these organs were also noticeable following exposure via the intravenous route. In contrast, most of the orally administered DPM was excreted quickly within a day. These results suggest that continuous inhalation exposure to DPM causes serious lung damage and may cause toxic effects in the extrapulmonary organs.

The association of meteorological parameters and AirQ+ health risk assessment of PM2.5 in Ratchaburi province, Thailand

Air quality is heavily influenced by rising pollution distribution levels which are a consequence of many artificial activities from numerous sources. This study aims to determine the relationship between meteorological data and air pollutants. The health effects of long-term PM_2.5 were estimated on expected life remaining (ELR) and years of life lost (YLL) indices in Ratchaburi province during the years 2015–2019 using AirQ+ software. Values obtained from the PM_2.5 averaging, and YLL data were processed for the whole population in the age range of 0–29, 30–60 and over 60. These values were entered into AirQ+ software. The mean annual concentration of PM_2.5 was highly variable, with the highest concentration being 136.42 μg/m³ and the lowest being 2.33 μg/m³. The results estimated that the highest and lowest YLL in the next 10 years for all age groups would be 24,970.60 and 11,484.50 in 2017 and 2019, respectively. The number of deaths due to COPD, IHD, and stroke related to long-term exposure to ambient PM_2.5 were 125, 27 and 26, respectively. The results showed that older people (> 64) had a higher YLL index than the groups aged under 64 years. The highest and lowest values for all ages were 307.15 (2015) and 159 (2017). Thus, this study demonstrated that the PM_2.5 effect to all age groups, especially the the elderly people, which the policy level should be awared and fomulated the stratergies to protecting the sensitive group.

Human health risk assessment of PM2.5-bound heavy metal of anthropogenic sources in the Khon Kaen Province of Northeast Thailand

The study aimed to assess the human health risk of PM_2.5-bound heavy metals from anthropogenic sources in Khon Kaen Province, Thailand between December 2020 and February 2021. According to the findings, the geometric mean concentration of PM_2.5 in the university area, residential area, industrial zone, and the agricultural zone was 32.78 μg/m³, 50.25 μg/m³, 44.48 μg/m³, and 29.53 μg/m³, respectively. The results showed that the estimated human health risk assessment, in terms of non-carcinogenic risks among children and adults in an urban area (residential and university), industrial zone, and the agricultural area, was of hazard index (HI) value of >1.0 indicating a greater chance of chronic effects occurring. This study showed that exposure to PM_2.5-bound heavy metal may increase the likelihood that lasting effects will result in a very high carcinogenic risk (CR) in children in residential areas, and an industrial zone with total carcinogenic risk (TCR) values of 0.23×101, and 0.12×101, respectively while resulting in a high TCR of 3.34×10−2 and 4.11×10−2 within the university areas and agricultural zone, respectively. In addition, health risk assessments among adults demonstrate high TCR values of 4.40×10−1 (residential area), 2.28×10−1 (industrial zone), and 7.70×10−3 (agricultural zone), thus indicating a potential health risk to adults living in these areas while the university area was very low effects on carcinogenic risk (CR≤10−8) for adults. Therefore, lowering the risk of exposure to PM_2.5 via the respiratory tract, for example, wearing a mask outside is a very effective self-defense strategy for people within and around the study site. This data study strongly supports the implementation of the air pollutant emission source reduction measures control and health surveillance.

Impact of Residential Concentration of PM2.5 Analyzed as Time-Varying Covariate on the Survival Rate of Lung Cancer Patients: A 15-Year Hospital-Based Study in Upper Northern Thailand

Air pollutants, especially particulate matter (PM) ≤ 2.5 µm (PM2.5) and PM ≤ 10 µm (PM10), are a major concern in upper northern Thailand. Data from a retrospective cohort comprising 9820 lung cancer patients diagnosed from 2003 to 2018 were obtained from the Chiang Mai Cancer Registry, and used to evaluate mortality and survival rates. Cox proportional hazard models were used to identify the association between the risk of death and risk factors including gender, age, cancer stage, smoking history, alcohol-use history, calendar year of enrollment, and time-updated PM2.5, PM10, NO₂ and O₃ concentrations. The mortality rate was 68.2 per 100 persons per year of follow-up. In a multivariate analysis, gender, age, cancer stage, calendar year of enrollment, and time-varying residential concentration of PM2.5 were independently associated with the risk of death. The lower the annually averaged PM2.5 and PM10 concentrations, the higher the survival probability of the patient. As PM2.5 and PM10 were factors associated with a higher risk of death, lung cancer patients who are inhabitant in the area should reduce their exposure to high concentrations of PM2.5 and PM10 to increase survival rates.

Spatial Estimation of PM2.5 Exposure and its Association with Asthma Exacerbation: A Prospective Study in Thai Children

Background:

The acceptable fine particulate matter (PM_2.5) level in Thailand is double the recommendation of the World Health Organization. It is necessary to have an accurate measure of PM_2.5 exposure and its association with health problems in vulnerable groups such as asthma exacerbation in Thai children to urge the Clean Air Act in Thailand, which is currently in the process of revision.

Objective:

To study the association between PM_2.5 exposure and asthma exacerbation in children living in Bangkok Metropolitan Region and Chiang Mai Province.

Methods:

A pilot prospective observational study was conducted at the Chest and Allergy clinic at Ramathibodi Hospital, Mahidol University, Bangkok and at the Chest Clinic at Nakornping Hospital, Chiang Mai, Thailand, from June 2020 to February 2021. Children with asthma, aged 5–18 years old, were recruited. Respiratory symptoms, including cough, chest tightness, dyspnea or wheezing, peak expiratory flow rate, and asthma exacerbation, were recorded twice daily by caregivers. Estimated average daily PM_2.5 exposure levels were calculated using ArcGIS® at exacerbation day, three days before exacerbation (lag day 3), and 7 days before exacerbation (lag day 7). Regression analysis was applied to examine the association between PM_2.5 exposure and asthma exacerbation.

Findings:

Seventy asthmatic patients were enrolled. The median age was 9.7 (IQR 5–18) years old. There were 53 respiratory symptoms, 5 admissions, and 1 intensive care unit admission. Daily PM_2.5 levels above 12 mcg/m³ (the US cut-off level for the sensitive group) has higher sensitivity to detect asthma exacerbation compared to Thai cut-off level for the sensitive group (37 mcg/m³) (sensitivity 98.2% vs 32.1%). The average daily PM_2.5 level exposure at lag day 3 in the exacerbation vs the non-exacerbation group was 27.5 and 13.6 mcg/m³ (p < 0.01), respectively. The daily PM_2.5 level at lag day 3 was also correlated with an acute asthmatic attack (r = 0.62, p < 0.01) with the 0.2 events increasing of asthmatic exacerbation every 10 mcg/m³ of increment of daily PM_2.5 level.

Conclusions:

Our findings suggest that asthmatic children are sensitive to daily PM_2.5 levels above 12 mcg/m³. Exposure to high daily PM_2.5 levels can lead to asthma exacerbation within three days. Further participant recruitment is needed to emphasize this association and establish the national data.

Evolution of Urban Haze in Greater Bangkok and Association with Local Meteorological and Synoptic Characteristics during Two Recent Haze Episodes

This present work investigates several local and synoptic meteorological aspects associated with two wintertime haze episodes in Greater Bangkok using observational data, covering synoptic patterns evolution, day-to-day and diurnal variation, dynamic stability, temperature inversion, and back-trajectories. The episodes include an elevated haze event of 16 days (14–29 January 2015) for the first episode and 8 days (19–26 December 2017) for the second episode, together with some days before and after the haze event. Daily PM_2.5 was found to be 50 µg m⁻³ or higher over most of the days during both haze events. These haze events commonly have cold surges as the background synoptic feature to initiate or trigger haze evolution. A cold surge reached the study area before the start of each haze event, causing temperature and relative humidity to drop abruptly initially but then gradually increased as the cold surge weakened or dissipated. Wind speed was relatively high when the cold surge was active. Global radiation was generally modulated by cloud cover, which turns relatively high during each haze event because cold surge induces less cloud. Daytime dynamic stability was generally unstable along the course of each haze event, except being stable at the ending of the second haze event due to a tropical depression. In each haze event, low-level temperature inversion existed, with multiple layers seen in the beginning, effectively suppressing atmospheric dilution. Large-scale subsidence inversion aloft was also persistently present. In both episodes, PM_2.5 showed stronger diurnality during the time of elevated haze, as compared to the pre- and post-haze periods. During the first episode, an apparent contrast of PM_2.5 diurnality was seen between the first and second parts of the haze event with relatively low afternoon PM_2.5 over its first part, but relatively high afternoon PM_2.5 over its second part, possibly due to the role of secondary aerosols. PM_2.5/PM₁₀ ratio was relatively lower in the first episode because of more impact of biomass burning, which was in general agreement with back-trajectories and active fire hotspots. The second haze event, with little biomass burning in the region, was likely to be caused mainly by local anthropogenic emissions. These findings suggest a need for haze-related policymaking with an integrated approach that accounts for all important emission sectors for both particulate and gaseous precursors of secondary aerosols. Given that cold surges induce an abrupt change in local meteorology, the time window to apply control measures for haze is limited, emphasizing the need for readiness in mitigation responses and early public warning.

The Effects of Fireworks Discharge on Atmospheric PM2.5 Concentration in the Chinese Lunar New Year

Discharging fireworks during the Chinese Lunar New Year celebrations is a deep-rooted custom in China. In this paper, we analyze the effect of this cultural activity on PM2.5 concentration using both ground observations and satellite data. By combining remote sensing data, the problem of uneven spatial distribution of ground monitoring has been compensated, and the research time span has been expanded. The results show that the extensive firework displays on New Year's Eve lead to a remarkable increase in nationwide PM2.5 concentration, which were 159~223% of the average level, indicating the instantaneous effect far exceeds that of any other factor over the whole year. However, the averaged PM2.5 concentrations of the celebration period were 0.99~16.32 μg/m3 lower compared to the average values of the corresponding pre-celebration period and post-celebration period, indicating the sustained effect is not very significant. The implementation of firework prohibition policies can greatly reduce the instantaneous PM2.5 increase, but no obvious air quality improvement is observed over the entire celebration period. Combining these findings and the cultural significance of this activity, we recommend that this custom is actively maintained, using new technologies and scientific governance programs to minimize the negative effects.