Air pollution and health in Sri Lanka: a review of epidemiologic studies

Monitoring of rainwater quality in Kandy and Peradeniya, Sri Lanka

The composition of atmospheric deposition is a measure of air quality, an important aspect of the health of the ecosystem. Consequently, continuous monitoring of atmospheric deposition is crucial to obtain remedial measures to avoid undesirable aspects that would affect living things. In this context, the objective of this study was to determine the rainwater quality at selected locations in Kandy and Peradeniya area of Sri Lanka, namely, Kandy, Polgolla, and University of Peradeniya (UOP), and to identify possible correlations between quality parameters through statistical means. Forty (40) rainwater samples from the UOP site and seven (07) samples each from the Kandy and Polgolla sites were collected from 18 May 2020 to 28 April 2021. The volume-weighted average (VWA) pH values of UOP, Kandy, and Polgolla sites were determined to be 7.44, 7.19, and 7.19, respectively, and moreover, acid rain (pH < 5.6) occurrences were not detected during the sampling period. The VWA values of rainfall, conductivity, salinity, TDS, and hardness at the UOP site were 40.12 mm, 51.93 μS cm-1, 0.0300 ppt, 26.59 mg L-1, and 13.55 mg L-1, respectively. The corresponding values of the Kandy site were 16.52 mm, 64.04 μS cm-1, 0.0361 ppt, 30.80 mg L-1, and 19.49 mg L-1, respectively; and those of the Polgolla site were 33.10 mm, 53.90 μS cm-1, 0.0310 ppt, 25.76 mg L-1, and 19.31 mg L-1, respectively. The VWA values of conductivity, salinity, and TDS were the highest at the Kandy site. Further, the VWA values of hardness at Kandy and Polgolla sites were approximately equal, probably due to the spring of Ca2+ and Mg2+ particulates from the dolomite quarry located in Digana area. The most prominent anion was identified as Cl- in bulk deposition at all three sites, while NO3- showed the lowest concentration of all sites. Moreover, very strong significant positive correlations were identified between conductivity-TDS, conductivity-salinity, conductivity-hardness, TDS-hardness, TDS-salinity, salinity-hardness, SO42--Cl-, and NO3--Cl- according to the relevant Pearson correlation coefficients. It is thus concluded that the pollutants come from the same sources, either natural or anthropogenic.

Indoor air pollutants and respiratory symptoms among residents of an informal urban settlement in Uganda: A cross-sectional study

BACKGROUND

Indoor air pollutants (IAP) and household conditions such as dampness, crowding and chemical exposures have been associated with acute and chronic respiratory infections. In Uganda, literature on the effects of IAP on respiratory outcomes in informal settlements is limited.

METHODS

We describe the baseline household characteristics of 284 adults and their children in an informal settlement in Uganda from April to May 2022. We monitored same-day indoor concentrations of particulate matter PM2.5, PM10, Carbon monoxide (CO), relative humidity %, and temperature from 9 am to 2 pm and interviewed caregivers/mothers about their respiratory symptoms and those of their children in the previous 30 days. We employed robust Poisson regressions to evaluate the associations between indoor air indicators and respiratory health symptoms.

RESULTS

Approximately 94.7% of households primarily used biomass fuels and 32.7% cooked from inside their dwelling rooms. The median PM2.5, PM10 and CO levels were 49.5 (Interquartile range (IQR) = 31.1,86.2) μg/m3, 73.6 (IQR = 47.3,130.5) μg/m3 and 7.70 (IQR = 4.1,12.5) ppm respectively. Among adults, a 10 unit increase in PM2.5 was associated with cough (Prevalence Ratio (PR) = 3.75, 95%CI 1.15-1.55). Dwelling unit dampness was associated with phlegm (PR = 2.53, 95%CI = 1.39-4.61) and shortness of breath (PR = 1.78, 95% CI 1.23-2.54) while cooking from outside the house was protective against shortness of breath (PR = 0.62, 95% CI = 0.44-0.87). In children, dampness was associated with phlegm (PR = 13.87, 95% CI 3.16-60.91) and cough (PR = 1.62, 95% CI 1.12-2.34) while indoor residual spraying was associated with phlegm (PR = 3.36, 95%CI 1.71-6.61).

CONCLUSION

Poor indoor air conditions were associated with respiratory symptoms in adults and children. Efforts to address indoor air pollution should be made to protect adults and children from adverse health effects.

How does the COVID-19-related restriction affect the spatiotemporal variability of ambient air quality in a tropical city?

The ambient air, a significant hazard to human health in most Indian cities, including Rourkela, is something we are strangely neglecting in the age of industrialization and urbanization. High levels of particulate matter released from various anthropogenic sources over the past decade have had a significant negative impact on the city. The COVID-19 lockdown situation brings understanding and realization towards the improvement of air quality and its subsequent effects. The present study investigates the impact of the COVID-19-related lockdown on the spatiotemporal variation of the ambient air quality in Rourkela City with a tropical climatic setup. The concentration and distribution of various pollutants are well explained by the wind rose and Pearson correlation. There is considerable spatiotemporal variation in the city's ambient air quality, as determined by a two-way ANOVA test comparing sampling sites and months. During the COVID-19 lockdown phases, the air quality of Rourkela witnessed an improvement in annual AQI ranging from 12.64 to 26.85% across the city. However, the air quality in the city deteriorated by 13.76-65.79% after the revocation of COVID-19 restrictions. The paired sample T-test justified that the air quality of Rourkela was significantly healthier in 2020 compared to both 2019 and 2021. Spatial interpolation reveals that the ambient air quality of Rourkela ranged from satisfactory to moderate categories throughout the entire study period. 31.93% area of the city has experienced an improvement in AQI from the Moderate to the satisfying category from 2019 to 2020, whereas about 68.78% area of the city has witnessed a decline in AQI from satisfactory to moderate category from 2020 to 2021.

Impact of solid fuel usage on respiratory symptoms among reproductive aged women: a cross-sectional study in Sri Lanka

BACKGROUND

Worldwide, around 3 billion people rely on solid fuel for their daily energy needs. Household air pollution secondary to solid fuel burning is a major risk factor for respiratory mobility among vulnerable populations. This study aimed to investigate the respiratory symptoms associated with solid fuel usage, the level of kitchen fuel smoke exposure and its association with respiratory symptoms among reproductive-aged women in Sri Lanka, where most households exclusively use firewood as the primary cooking fuel.

METHODS

A descriptive cross-sectional study was conducted among 403 reproductive-aged women (15 to 49 years) in the Central Province, Sri Lanka. A structured interviewer-administered questionnaire was used to collect data, and an exposure assessment was done using a breath carbon monoxide monitor.

RESULTS

After adjusting for potential confounding factors by the logistic regression models, the odds ratios (OR) of the liquid petroleum gas-only users for at least one respiratory symptom relevant to cough (OR: 0.39; 95% confidence interval [CI]: 0.20-0.78), wheezing (OR: 0.47; 95% [CI]: 0.26-0.87), and dyspnea (OR: 0.44; 95% CI: 0.24-0.84) were significantly lower compared to firewood-only users. The mean of expired air carbon monoxide and estimated carboxyhemoglobin levels of liquid petroleum gas-only users (2.84 ± 2.85 ppm; 1.08 ± 0.46%) were significantly lower than those of firewood-only users (5.27 ± 4.64 ppm; 1.47 ± 0.74%).

CONCLUSIONS

The use of firewood increased the risk of respiratory symptoms among reproductive-aged women in Sri Lanka. Health education focused on positive behavioral changes and effective and efficient clean energy policies are recommended to mitigate the risk associated with solid fuel smoke exposure.

Applying the indexing system for assessment of effectiveness of the exhaust emission compliance certification process for passenger cars

The inspection/maintenance programmes exist in most countries, aiming at vehicular emission reduction through exhaust emission monitoring and compliance policy to the extant norms. However, considering the absence of an intra-vehicle approach, the higher success rate of vehicles towards compliance policy remains a grey area. The paper attempts to examine this issue through the application of an exhaust emission index (EEI) for petrol-driven cars. The study observed two different scales finding that the Bharat Stage emission norm scale method reports lower ranges of EEI compared with the linear scale (LS) method (EEI min-BSNS  = 1.12 and EEI min-LS  = 1.25; EEI max-BSNS  = 20.70 and EEI max-LS  = 29.54). The LS method and the maximum operator form of aggregation are recommended as these can find the highest number of non-compliant cars (21.81% and 12.03% of the ‘poor’ class, respectively) in the whole fleet tested. The EEI gives a more scientific approach to vehicular emission evaluation, like what the air quality index does in the case of the ambient air quality. It helps vehicle owners know their car's emission status as a quick reference index (EEI). The accurate status of such emission further helps the policymakers affect the better phasing-out norms.

Effects of Indoor Air Pollution on the Development of Children under Five Years of Age in Sri Lanka

Air pollution is a multifaceted environmental toxin affecting the Central Nervous System (CNS) through diverse pathways. The CNS of young children is particularly susceptible to the detrimental effects of toxins, as brain development continues postnatally with the formation of interneuronal connections, glial cell proliferation and myelination of axons. Indoor air pollution (IAP) from solid fuel combustion is more harmful than outdoor air pollution. Numerous air pollutants hazardous to health are released during the burning of unprocessed biomass. The primary source of fuel in Sri Lanka for cooking is biomass, mainly wood. In this study, we evaluated the influence of IAP resulting from biomass combustion on the neurodevelopment of children. In a cohort of children under five years living in a semi-urban area of Sri Lanka, neurodevelopment was assessed using Denver II developmental screening test. Air quality levels were measured (Carbon Monoxide (CO) and Particulate Matter 2.5 (PM2.5)) in a subsample. There were significantly high levels of CO and PM2.5 in the ambient air of households using biomass as the primary fuel for cooking. Children living in these households had a significantly higher number of children with ‘suspect’ developmental assessment scores in the language, social behavior and play and gross motor development domains.

Characterization of airborne PAHs and metals associated with PM10 fractions collected from an urban area of Sri Lanka and the impact on airway epithelial cells

Airborne particulate matter (PM), polycyclic aromatic hydrocarbons (PAHs) and heavy metals (HMs) are significant contributors leading to many human health issues. Thus, this study was designed to perform chemical analysis and biological impact of airborne particulate matter 10 (PM₁₀) in the World heritage City of Kandy City in Sri Lanka. 12 priority PAHs and 34 metals, including 10 highly toxic HMs were quantified. The biological effects of organic extracts were assayed using an in vitro primary porcine airway epithelial cell culture model. Cytotoxicity, DNA damage, and gene expressions of selected inflammatory and cancer-related genes were also assessed. Results showed that the total PAHs ranged from 3.062 to 36.887 ng/m³. The metals were dominated by Na > Ca > Mg > Al > K > Fe > Ti, while a few toxic HMs were much higher in the air than the existing ambient air quality standards. In the bioassays, a significant cytotoxicity (p < 0.05) was observed at 300 μg/mL treatment, and significant (p < 0.05) DNA damages were noted in all treatment groups. All genes assessed were found to be significantly up-regulated (p < 0.05) after 24 h of exposure and after 48 h, only TGF-β1 and p53 did not significantly up-regulate (p < 0.05). These findings confirm that the Kandy city air contains potential carcinogenic and mutagenic compounds and thus, exposure to Kandy air may increase the health risks and respiratory tract-related anomalies.

Ambient PM2.5 and PM10 Exposure and Respiratory Disease Hospitalization in Kandy, Sri Lanka

Evidence of associations between exposure to ambient air pollution and health outcomes are sparse in the South Asian region due to limited air pollution exposure and quality health data. This study investigated the potential impacts of ambient particulate matter (PM) on respiratory disease hospitalization in Kandy, Sri Lanka for the year 2019. The Generalized Additive Model (GAM) was applied to estimate the short-term effect of ambient PM on respiratory disease hospitalization. As the second analysis, respiratory disease hospitalizations during two distinct air pollution periods were analyzed. Each 10 μg/m³ increase in same-day exposure to PM_2.5 and PM₁₀ was associated with an increased risk of respiratory disease hospitalization by 1.95% (0.25, 3.67) and 1.63% (0.16, 3.12), respectively. The effect of PM_2.5 or PM₁₀ on asthma hospitalizations were 4.67% (1.23, 8.23) and 4.04% (1.06, 7.11), respectively (p < 0.05). The 65+ years age group had a higher risk associated with PM_2.5 and PM₁₀ exposure and hospital admissions for all respiratory diseases on the same day (2.74% and 2.28%, respectively). Compared to the lower ambient air pollution period, higher increased hospital admissions were observed among those aged above 65 years, males, and COPD and pneumonia hospital admissions during the high ambient air pollution period. Active efforts are crucial to improve ambient air quality in this region to reduce the health effects.

Household Air Pollution from Biomass Fuel for Cooking and Adverse Fetal Growth Outcomes in Rural Sri Lanka

The aim of this study was to investigate the impact of biomass fuel for cooking on adverse fetal growth outcomes in Sri Lanka. A cross-sectional study of mothers recruited at maternity clinics in rural communities in Sri Lanka’s Central Province was undertaken. Data pertaining to household air pollution and fetal growth parameters were collected using an interviewer-administered questionnaire. Logistic regression models, adjusted for potential confounders, were used to evaluate the impact of biomass fuel for cooking on low birth weight (LBW) and small for gestational age (SGA) parameters. Findings showed that exposure to biomass cooking fuels during pregnancy was associated with an increased risk of LBW adjusted odds ratio (aOR) 2.74 (95% CI 1.08–6.96) and SGA (aOR: 1.87, 95% CI 1.03–3.41) compared with the use of clean energy. The risk of LBW was highest for traditional biomass stoves compared to improved biomass stoves (aOR: 3.23, 95% 1.17–8.89) and biomass use in kitchens without a chimney compared to kitchens with a chimney (aOR: 4.63, 95% 1.54–13.93). Similar trends were observed for SGA.

Dietary exposure assessment of cadmium, arsenic, and lead in market rice from Sri Lanka

Rice is frequently reported to be contaminated with heavy metals (HMs); thus, the human health risks from its consumption have received increasing attention. A total of 165 commercial rice samples from Sri Lanka were collected to determine their cadmium (Cd), arsenic (As), and lead (Pb) concentrations. The exposure risk for Sri Lankans from the estimated daily intakes (EDIs) of these toxicants was assessed. Simultaneously, non-carcinogenic and carcinogenic risks were evaluated using hazard quotients (HQs) and the hazard index (HI). The results revealed that the average levels of Cd, As, and Pb in commercial rice were 0.080 ± 0.130, 0.077 ± 0.040, and 0.031 ± 0.050 mg/kg, respectively, with ranges of 0.003-0.727, 0.019-0.217, and 0.001-0.345 mg/kg (expressed on a dry weight basis), respectively. The average EDIs of Cd, inorganic As (iAs), and Pb were 0.772, 0.490, and 0.306 μg/kg body weight (bw)/day, respectively; these were below provisional tolerable weekly intake (PTWI) values recommended by the Joint FAO/WHO Expert Committee on Food Additives (JECFA), but iAs was above the recommended reference doses (RfDs) recommended by the United States Environmental Protection Agency (USEPA). However, approximately 25% and 75% of the Cd and iAs HQs for the Sri Lankan population, respectively, were greater than 1, suggesting a potential health risk, whereas the HQs for Pb was less than 1. Considering the additive effect, HI values of the P90, P95, P97.5, and P99 percentiles would reach 4.773, 6.458, 8.392, and 11.614, implying that intake of the combined metals might result in potential health risks.

Renal bioaccumulation of trace elements in urban and rural Sri Lankan populations: A preliminary study based on post mortem tissue analysis

INTRODUCTION

Environmental pollution, especially by toxic trace elements, is a global health concern. Heavy metals such as Cadmium (Cd), Arsenic (As) and Lead (Pb) are associated with numerous disorders and are considered by some as an aetiological factor for the Chronic Kidney Disease (CKDu1) epidemic in Sri Lanka. This study explores patterns of bioaccumulation of six trace elements in kidneys obtained during forensic autopsies from urban and rural regions in Sri Lanka.

METHODS

Kidney samples obtained from one urban district (n = 13) and three rural districts (n = 18) were lyophilized, microwave digested and profiled by ICP-MS techniques.

RESULTS AND DISCUSSION

The mean age of the sampled population was 47.9 ± 11.3 yrs. Median (IQR) for Cd, As, Pb, Cr, Zn and Se were, 14.67(8.04-22.47) μg/g, 0.44(0.29-0.56) μg/g, 0.11(0.07-0.30) μg/g, 0.15(0.1096-0.3274), 25.55(17.24-39.35) μg/g and 0.52(0.37-0.84) μg/g, respectively. Cd, Zn and Se levels were significantly higher (p < 0.05) among the urban samples compared to that of the rural group. Zn and Se levels were higher among younger age groups. As, Pb and Cr did not show any significant differences between the two cohorts nor any correlations with age.

CONCLUSION

This population-specific baseline study provides an insight into the differences in exposure to toxic trace elements and essential elements between urban and rural populations. Residents in CKDu affected rural districts did not appear to be at risk of toxic heavy metal exposure, however their renal bioaccumulation of nephroprotective essential elements was lower than urban residents.

Effect of household air pollution due to solid fuel combustion on childhood respiratory diseases in a semi urban population in Sri Lanka

BACKGROUND

Household air pollution from combustion of solid fuels for cooking and space heating is one of the most important risk factors of the global burden of disease. This study was aimed to determine the association between household air pollution due to combustion of biomass fuel in Sri Lankan households and self-reported respiratory symptoms in children under 5 years.

METHODS

A prospective study was conducted in the Ragama Medical Officer of Health area in Sri Lanka. Children under 5 years were followed up for 12 months. Data on respiratory symptoms were extracted from a symptom diary. Socioeconomic data and the main fuel type used for cooking were recorded. Air quality measurements were taken during the preparation of the lunch meal over a 2-h period in a subsample of households.

RESULTS

Two hundred and sixty two children were followed up. The incidence of infection induced asthma (RR = 1.77, 95%CI;1.098-2.949) was significantly higher among children resident in households using biomass fuel and kerosene (considered as the high exposure group) as compared to children resident in households using Liquefied Petroleum Gas (LPG) or electricity for cooking (considered as the low exposure group), after adjusting for confounders. Maternal education was significantly associated with the incidence of infection induced asthma after controlling for other factors including exposure status. The incidence of asthma among male children was significantly higher than in female children (RR = 1.17; 95% CI 1.01-1.37). Having an industry causing air pollution near the home and cooking inside the living area were significant risk factors of rhinitis (RR = 1.39 and 2.67, respectively) while spending less time on cooking was a protective factor (RR = 0.81). Houses which used biomass fuel had significantly higher concentrations of carbon monoxide (CO) (mean 2.77 ppm vs 1.44 ppm) and particulate matter_2.5 (PM_2.5) (mean 1.09 mg/m³ vs 0.30 mg/m³) as compared to houses using LPG or electricity for cooking.

CONCLUSION

The CO and PM_2.5 concentrations were significantly higher in households using biomass fuel for cooking. There was a 1.6 times higher risk of infection induced asthma (IIA) among children of the high exposure group as compared to children of the low exposure group, after controlling for other factors. Maternal education was significantly associated with the incidence of IIA after controlling for exposure status and other variables.

Geostatistical predictive modeling for asthma and chronic obstructive pulmonary disease using socioeconomic and environmental determinants

The spatial distribution of the prevalence of asthma and chronic obstructive pulmonary disease (COPD) remains under the influence of a wide array of environmental, climatic, and socioeconomic determinants. However, a large proportion of these influences remain unexplained. In completion, this study examined the spatial associations between asthma/COPD morbidity and their determinants using ordinary least squares (OLS) and geographically weighted regressions (GWR). Inpatient records collected from the secondary and tertiary care hospitals in Kandy from 2010 to 2014 were considered as the dependent variable. Potential risk factors (explanatory variables) were identified in four distinguished classes: 1) meteorological factors, (2) direct and indirect factors of air pollution, (3) socioeconomic factors, and (4) characteristics of the physical environment. All possible combinations of candidate explanatory variables were evaluated through an exploratory regression. A comparison between the regression models was also explored. The best OLS regression models revealed about 55% of asthma variation and 62% of COPD variation while GWR models yielded 78% and 74% of the variation of asthma and COPD occurrences respectively. Relative humidity, proximity to roads (0-200 m), road density, use of firewood as a source of fuel, and elevation play a vital role in predicting morbidity from asthma and COPD. Both local and global regression models are important in assessing spatial relationships of asthma and COPD. However, the local models exhibit a better prediction capability for assessing non-stationary relationships of asthma and COPD than global models. The geostatistical aspects used in this study may also provide insights for evaluating heterogeneous environmental risk factors in other epidemiological studies across different spatial settings.

Assessment of Airborne Bacterial and Fungal Communities in Selected Areas of Teaching Hospital, Kandy, Sri Lanka

Nosocomial infections, in lay term known as hospital acquired infections, are caused mainly by airborne pathogens found in healthcare facilities and their surroundings. The aim of this study was to quantify and identify bacteria and fungi in a hospital, which is an understudied area of air quality in Sri Lanka. Air samples were collected in agar medium and petri plates containing sterile filter papers. The number of culturable and total airborne microorganisms was estimated by manual counting and fluorescent microscopy, respectively. The morphologically distant bacteria and fungi were identified by DNA sequencing. The statistical analysis revealed significant variances between studied sites (p < 0.05) where Outpatients Department and Respiratory Unit showed higher levels of airborne microbial load. Culturable microbial count was higher at noon (hospital visiting hours) compared to other sampling periods (after hospital visiting hours) within the hospital. Total count of airborne microbes was found to be the highest during the afternoon. The most sensitive zones such as Operating Theatre and Intensive Care Unit showed considerably higher counts of airborne microbes. Identification by molecular means revealed the presence of human pathogens in the hospital air including Bacillus sp, Micrococcus sp, Pseudomonas sp, Staphylococcu ssp, Exiguobacterium sp, Enterobacter sp, Escherichia sp, Sphingomonas sp, Massilia sp, Kocuria sp, Fusarium sp, and Aspergillus sp. In conclusion, the results from this study indicate that the hospital air was generally contaminated. Therefore, the implementation of proactive policies and strategies are needed to monitor hospital air quality in sensitive zones as well as other areas of the hospitals.

Building and indoor environmental quality assessment of Nigerian primary schools: A pilot study

A total of 15 classrooms went through on-site assessments/inspections, including measurements of temperature (T), and concentrations of carbon monoxide (CO) and carbon dioxide (CO₂ ). In addition, the level of surface biocontamination/cleaning effectiveness was assessed by measuring adenosine triphosphate (ATP) levels on students' desks. Based on the data, the quality of facilities in the buildings was low. Classroom occupancy exceeded ASHRAE 50 person/100 m² standard in all cases indicating overcrowding. However, concentrations of CO₂ remained below 1000 ppm in most classrooms. On the other hand, indoor T was above the recommended levels for thermal comfort in all classrooms. Maximum indoor CO was 6 ppm. Median ATP concentrations on the desk tops were moderately high in all schools. The use of open incinerators and power generator sets near classrooms, which was suspected to be the main source of CO, should be discouraged. Improved hygiene could be achieved by providing the students access to functioning bathroom facilities and cafeteria, and by effective cleaning of high contact surfaces such as desks. Although ventilation seems adequate based on CO₂ concentrations, thermal comfort was not attained especially in the afternoon during extreme sunlight. Therefore, installing passive and/or mechanical cooling systems should be considered in this regard.

Children's Environmental Health in South and Southeast Asia: Networking for Better Child Health Outcomes

Children are particularly vulnerable to environmental hazards because they receive higher doses of pollutants in any given environment and often do not have equitable access to social protection mechanisms such as environmental and health care services. The World Health Organization established a global network of collaborating centres that address children’s environmental health (CEH). The network developed a focus on low- and middle-income countries (LMICs) and is broadening its reach by conducting regional workshops for CEH.

The association between local meteorological changes and exacerbation of acute wheezing in Kandy, Sri Lanka

BACKGROUND

Severe wheezing is a common medical emergency. Past studies have demonstrated associations between exacerbation of wheezing and meteorological factors and atmospheric pollution. There are no past studies from Sri Lanka that analyzed correlation between daily multiple meteorological variables and exacerbation of wheezing.

OBJECTIVES

To determine the correlations between daily counts of patients nebulized at the Outpatient Department (OPD) of Teaching Hospital - Kandy (THK) and local meteorological variables, and to explore the utility of that information.

DESIGN

We considered daily counts of patients nebulized at the OPD of THK as an indicator of exacerbations of wheezing in the population catered to by this hospital. We determined the correlations between daily counts of patients nebulized at OPD and the following meteorological variables for four years: daily rainfall, minimum temperature, maximum temperature, diurnal temperature range, difference between maximum temperature and the temperature at 1800 hours, daytime humidity, nighttime humidity, barometric pressure and visibility. We utilized wavelet time series method for data analysis.

RESULTS

All nine meteorological parameters studied were correlated with the daily counts of patients nebulized with average lag periods ranging from 5 to 15 days. Peaks of daily rainfall, maximum temperature, diurnal temperature range, difference between maximum temperature and the temperature at 1800 hours and daytime humidity were followed by peaks of counts of patients nebulized (positive correlations). Troughs of minimum temperature, nighttime humidity, barometric pressure and visibility were followed by peaks of patients nebulized (negative correlations).

CONCLUSIONS

The THK shall expect more patients with acute wheezing after extremes of weather. Minimum temperature has been consistently correlated with the exacerbation of respiratory symptoms in the past studies in other countries as well. Hence, prescribing the inhalation of more drugs on unusually cold days (prophylactically) may help prevent acute exacerbation of wheezing in patients on treatment for asthma and COPD.

Health Effects of Ambient Air Pollution in Developing Countries

The deleterious effects of ambient air pollution on human health have been consistently documented by many epidemiologic studies worldwide, and it has been calculated that globally at least seven million deaths are annually attributable to the effects of air pollution. The major air pollutants emitted into the atmosphere by a number of natural processes and human activities include nitrogen oxides, volatile organic compounds, and particulate matter. In addition to the poor ambient air quality, there is increasing evidence that indoor air pollution also poses a serious threat to human health, especially in low-income countries that still use biomass fuels as an energy resource. This review summarizes the current knowledge on ambient air pollution in financially deprived populations.

A comparative study of human exposures to household air pollution from commonly used cookstoves in Sri Lanka

Solid fuel burning cookstoves are a major source of household air pollution (HAP) and a significant environmental health risk in Sri Lanka. We report results of the first field study in Sri Lanka to include direct measurements of both real-time indoor concentrations and personal exposures of fine particulate matter (PM_2.5 ) in households using the two most common stove types in Sri Lanka. A purposive sample of 53 households was selected in the rural community of Kopiwatta in central Sri Lanka, roughly balanced for stove type (traditional or improved 'Anagi') and ventilation (chimney present or absent). At each household, 48-h continuous real-time measurements of indoor kitchen PM_2.5 and personal (primary cook) PM_2.5 concentrations were measured using the RTI MicroPEM^™ personal exposure monitor. Questionnaires were used to collect data related to household demographics, characteristics, and self-reported health symptoms. All primary cooks were female and of an average age of 47 years, with 66% having completed primary education. Median income was slightly over half the national median monthly income. Use of Anagi stoves was positively associated with a higher education level of the primary cook (P = 0.026), although not associated with household income (P = 0.18). The MicroPEM monitors were well-received by participants, and this study's valid data capture rate exceeded 97%. Participant wearing compliance during waking hours was on average 87.2% on Day 1 and 83.3% on Day 2. Periods of non-compliance occurred solely during non-cooking times. The measured median 48-h average indoor PM_2.5 concentration for households with Anagi stoves was 64 μg/m³ if a chimney was present and 181 μg/m³ if not. For households using traditional stoves, these values were 70 μg/m³ if a chimney was present and 371 μg/m³ if not. Overall, measured indoor PM_2.5 concentrations ranged from a minimum of 33 μg/m³ to a maximum of 940 μg/m³ , while personal exposure concentrations ranged from 34 to 522 μg/m³ . Linear mixed effects modeling of the dependence of indoor concentrations on stove type and presence or absence of chimney showed a significant chimney effect (65% reduction; P < 0.001) and an almost significant stove effect (24% reduction; P = 0.054). Primary cooks in households without chimneys were exposed to substantially higher levels of HAP than those in households with chimneys, while exposures in households with traditional stoves were moderately higher than those with improved Anagi stoves. As expected, simultaneously measuring both indoor concentrations and personal exposure levels indicate significant exposure misclassification bias will likely result from the use of a stationary monitor as a proxy for personal exposure. While personal exposure monitoring is more complex and expensive than deploying simple stationary devices, the value an active personal PM monitor like the MicroPEM adds to an exposure study should be considered in future study designs.

Sri Lanka Pilot Study to Examine Respiratory Health Effects and Personal PM2.5 Exposures from Cooking Indoors

A pilot study of indoor air pollution produced by biomass cookstoves was conducted in 53 homes in Sri Lanka to assess respiratory conditions associated with stove type ("Anagi" or "Traditional"), kitchen characteristics (e.g., presence of a chimney in the home, indoor cooking area), and concentrations of personal and indoor particulate matter less than 2.5 micrometers in diameter (PM2.5). Each primary cook reported respiratory conditions for herself (cough, phlegm, wheeze, or asthma) and for children (wheeze or asthma) living in her household. For cooks, the presence of at least one respiratory condition was significantly associated with 48-h log-transformed mean personal PM2.5 concentration (PR = 1.35; p < 0.001). The prevalence ratio (PR) was significantly elevated for cooks with one or more respiratory conditions if they cooked without a chimney (PR = 1.51, p = 0.025) and non-significantly elevated if they cooked in a separate but poorly ventilated building (PR = 1.51, p = 0.093). The PRs were significantly elevated for children with wheeze or asthma if a traditional stove was used (PR = 2.08, p = 0.014) or if the cooking area was not partitioned from the rest of the home (PR = 2.46, p = 0.012). For the 13 children for whom the cooking area was not partitioned from the rest of the home, having a respiratory condition was significantly associated with log-transformed indoor PM2.5 concentration (PR = 1.51; p = 0.014).

Lung disease in a global context. A call for public health action

As described in a recently released report of the Forum of International Respiratory Societies, four of the leading causes of death in the world are chronic obstructive pulmonary disease, acute respiratory tract infections, lung cancer, and tuberculosis. A fifth, asthma, causes enormous global morbidity. Not enough progress has been made in introducing new therapies and reducing disease burden for these illnesses in the last few decades, despite generous investments and some notable progress in biomedical research. Four external and modifiable drivers are responsible for a substantial percentage of the disease burden represented by the major lung diseases: tobacco, outdoor air pollution, household air pollution, and occupational exposures to lung toxins. Especially in low- and middle-income countries, but in highly developed economies as well, pressures for economic development and lax regulation are contributing to the continued proliferation of these drivers. Public health approaches to the most common lung diseases could have enormous effects on reducing morbidity and mortality. There must be increased advocacy from and mobilization of civil society to bring attention to the drivers of lung diseases in the world. The World Health Organization should negotiate accords similar to the Framework Convention on Tobacco Control to address air pollution and occupational exposures. Large increases in funding by government agencies and nongovernmental organizations around the world are needed to identify technologies that will reduce health risks while allowing populations to enjoy the benefits of economic development. This paradigm, focused more on public health than on individual medical treatment, has the best chance of substantial reduction in the burden of lung disease around the world in the next several years.

Capacity building in environmental and occupational health in Sri Lanka

BACKGROUND

Although environmental and occupational health (EOH) research and services in Sri Lanka have a long history, policies related to EOH are outdated.

METHODS

We review the International Training and Research in Environmental and Occupational Health (ITREOH) program in Sri Lanka that commenced in 2006 as a collaboration between the University of Alabama at Birmingham and the Faculty of Medicine of the University of Kelaniya, Sri Lanka.

RESULTS

The program has trained over 20 scientists in conducting EOH research. New pioneering research in EOH was initiated. The program was instrumental in furthering the training and research in EOH by initiating a MPH degree program, the first in the country.

CONCLUSIONS

The program has established North-South, South-South and in-country collaborations between institutions and scientists, increasing the visibility of EOH in the future.

Respiratory health status of children from two different air pollution exposure settings of Sri Lanka: a cross-sectional study

BACKGROUND

Health effects due to air pollution is becoming a major public health problem with growing traffic congestion and establishment of small- to medium-scale industries with poor emission controls in urban cities of Sri Lanka.

METHODS

Respiratory health status of 7- to 10-year-old children in two settings (urban and semi-urban) was assessed using standard questionnaires. Information on socio-demographic characteristics and potential determinants of both outdoor and indoor air pollutants exposure levels were also obtained. The respiratory health status of children in the two settings was compared.

RESULTS

We found that children from the urban setting had a significantly higher prevalence of wheezing within the last 12 months as compared to children from the semi-urban setting (adjusted OR = 2.02; 95% CI = 1.13-3.59). Indoor cooking with unclean fuels was a risk factor for wheezing independent of the area of residence (adjusted OR = 1.57; 95% CI = 1.01-2.46).

CONCLUSIONS

Poor indoor air quality was a major determinant of wheezing for the overall study group. Children from urban areas of Sri Lanka have poorer respiratory health status as compared to children from semi-urban areas. Besides poor outdoor air quality, this difference may also be due to other unexplored factors which may differ between urban and semi-urban areas in Sri Lanka.

The effects of air pollution on respiratory health in susceptible populations: a multilevel study in Bucaramanga, Colombia

We conducted a cohort study to investigate the association between exposure to three different levels of outdoor air pollution and incidence of respiratory symptoms in a population with chronic cardiovascular and respiratory disease. We accompanied 756 participants for a period of six months through the maintenance of a daily record of symptoms and clinic visits. The symptoms with highest incidence rates were sneezing and hacking cough. Multivariate analysis showed that incidence of total symptoms was 60% and 74% lower in areas with medium and low levels of pollution compared to areas with high levels of pollution. These results suggest that negative respiratory effects occur at concentrations of particulate matter PM10 > 60ug/m³.

A profile of biomass stove use in Sri Lanka

A large body of evidence has confirmed that the indoor air pollution (IAP) from biomass fuel use is a major cause of premature deaths, and acute and chronic diseases. Over 78% of Sri Lankans use biomass fuel for cooking, the major source of IAP in developing countries. We conducted a review of the available literature and data sources to profile biomass fuel use in Sri Lanka. We also produced two maps (population density and biomass use; and cooking fuel sources by district) to illustrate the problem in a geographical context. The biomass use in Sri Lanka is limited to wood while coal, charcoal, and cow dung are not used. Government data sources indicate poor residents in rural areas are more likely to use biomass fuel. Respiratory diseases, which may have been caused by cooking emissions, are one of the leading causes of hospitalizations and death. The World Health Organization estimated that the number of deaths attributable to IAP in Sri Lanka in 2004 was 4300. Small scale studies have been conducted in-country in an attempt to associate biomass fuel use with cataracts, low birth weight, respiratory diseases and lung cancer. However, the IAP issue has not been broadly researched and is not prominent in Sri Lankan public health policies and programs to date. Our profile of Sri Lanka calls for further analytical studies and new innovative initiatives to inform public health policy, advocacy and program interventions to address the IAP problem of Sri Lanka.

Urban city transportation mode and respiratory health effect of air pollution: a cross-sectional study among transit and non-transit workers in Nigeria

OBJECTIVES

To assess the respiratory health effect of city ambient air pollutants on transit and non-transit workers and compare such effects by transportation mode, occupational exposure and sociodemographic characteristics of participants.

DESIGN

Cross-sectional, randomised survey.

SETTING

A two primary healthcare centre survey in 2009/2010 in Uyo metropolis, South-South Nigeria.

PARTICIPANTS

Of the 245 male participants recruited, 168 (50 taxi drivers, 60 motorcyclists and 58 civil servants) met the inclusion criteria. These include age 18-35 years, a male transit worker or civil servant who had worked within Uyo metropolis for at least a year prior to the study, and had no history of respiratory disorders/impairment or any other debilitating illness.

MAIN OUTCOME MEASURE

The adjusted ORs for respiratory function impairment (force vital capacity (FVC) and/or FEV(1)<80% predicted or FEV(1)/FVC<70% predicted) using Global Initiative for Chronic Obstructive Lung Diseases (GOLD) and National Institute for Health and Clinical Excellence (NICE) criteria were calculated. In order to investigate specific occupation-dependent respiratory function impairment, a comparison was made between the ORs for respiratory impairment in the three occupations. Adjustments were made for some demographic variables such as age, BMI, area of residence, etc.

RESULTS

Exposure to ambient air pollution by occupation and transportation mode was independently associated with respiratory functions impairment and incident respiratory symptoms among participants. Motorcyclists had the highest effect, with adjusted OR 3.10, 95% CI 0.402 to 16.207 for FVC<80% predicted and OR 1.71, 95% CI 0.61 to 4.76 for FEV(1)/FVC<70% predicted using GOLD and NICE criteria. In addition, uneducated, currently smoking transit workers who had worked for more than 1 year, with three trips per day and more than 1 h transit time per trip were significantly associated with higher odds for respiratory function impairment at p<0.001, respectively.

CONCLUSIONS

Findings of this study lend weights to the existing literature on the adverse respiratory health effect of ambient air pollution on city transit workers globally. The role of other confounders acting synergistically to cause a more deleterious effect is obvious. In all, the effect depends on the mode and duration of exposure.