Constituents of fine particulate matter and asthma in six low- and middle-income countries

BACKGROUND: Scientific understanding of indoor air pollution is predominately based on research carried out in cities in high‐income countries (HICs). Less is known about how pollutant concentrations change over the course of a typical day in cities in low‐ and middle‐income countries (LMICs).OBJECTIVE: To understand how concentrations of fine particulate matter smaller than 2.5 microns in diameter (PM2.5) change over the course of the day outdoors (across a range of countries) and indoors (using measurements from Dhaka, Bangladesh).DESIGN: Data on PM2.5 concentrations were gathered from 779 households in Dhaka as part of the MCLASS II (Muslim Communities Learning About Second‐hand Smoke in Bangladesh) project, and compared to outdoor PM2.5 concentrations to determine the temporal variation in exposure to air pollution. Hourly PM2.5 data from 23 cities in 14 LMICs, as well as London (UK), Paris (France) and New York (NY, USA), were extracted from publicly available sources for comparison.RESULTS: PM2.5 in homes in Dhaka demonstrated a similar temporal pattern to outdoor measurements, with greater concentrations at night than in the afternoon. This pattern was also evident in 19 of 23 LMIC cities.CONCLUSION: PM2.5 concentrations are greater at night than during the afternoon in homes in Dhaka. Diurnal variations in PM2.5 in LMICs is substantial and greater than in London, Paris or New York. This has implications for public health community approaches to health effects of air pollution in LMICs.

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Exposure to landscape fire smoke extremely reduced birthweight in low- and middle-income countries

10.1101/2021.04.27.21256225 ◽

2021 ◽

Author(s):

jiajianghui li ◽

Tianjia Guan ◽

Qian Guo ◽

Guannan Geng ◽

Huiyu Wang ◽

...

Keyword(s):

Fixed Effects ◽

Low Birthweight ◽

Fine Particulate Matter ◽

Binary Outcomes ◽

Middle Income ◽

Middle Income Countries ◽

Gestational Exposure ◽

Fire Smoke ◽

Fixed Effects Regression ◽

Low And Middle Income

Landscape fire smoke (LFS) has been associated with reduced birthweight, but evidence from low and middle income countries (LMICs) is rare. Here, we present a sibling matched case control study of 227,948 newborns to identify an association between fire sourced fine particulate matter (PM2.5) and birthweight in 54 LMICs from 2000 to 2014. We selected mothers from the geocoded Demographic and Health Survey with at least two children and valid birthweight records. Newborns affiliated with the same mother were defined as a family group. Gestational exposure to LFS was assessed in each newborn using the concentration of fire sourced PM2.5. We determined the associations of the within group variations in LFS exposure with birthweight differences between matched siblings using a fixed effects regression model. Additionally, we analyzed the binary outcomes of low birthweight (LBW) or very low birthweight (VLBW). According to fully adjusted models, a 1 ug/m3 increase in the concentration of fire sourced PM2.5 was significantly associated with a 2.17 g (95% confidence interval [CI]: 0.56, 3.77) reduction in birthweight, a 2.80% (95% CI: 0.97, 4.66) increase in LBW risk, and an 11.68% (95% CI: 3.59, 20.40) increase in VLBW risk. Our findings indicate that gestational exposure to LFS harms maternal health.

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Early-life exposure to ambient fine particulate air pollution and infant mortality: pooled evidence from 43 low- and middle-income countries

International Journal of Epidemiology ◽

10.1093/ije/dyz090 ◽

2019 ◽

Vol 48 (4) ◽

pp. 1125-1141 ◽

Cited By ~ 9

Author(s):

Nihit Goyal ◽

Mahesh Karra ◽

David Canning

Keyword(s):

Air Pollution ◽

Infant Mortality ◽

Neonatal Mortality ◽

Early Life ◽

Middle Income ◽

Middle Income Countries ◽

Particulate Air Pollution ◽

Fine Particulate ◽

Early Life Exposure ◽

Low And Middle Income

Abstract Background Many low- and middle-income countries are experiencing high and increasing exposure to ambient fine particulate air pollution (PM2.5). The effect of PM2.5 on infant and child mortality is usually modelled using concentration response curves extrapolated from studies conducted in settings with low ambient air pollution, which may not capture its full effect. Methods We pool data on more than half a million births from 69 nationally representative Demographic and Health Surveys that were conducted in 43 low- and middle-income countries between 1998 and 2014, and we calculate early-life exposure (exposure in utero and post partum) to ambient PM2.5 using high-resolution calibrated satellite data matched to the child’s place of residence. We estimate the association between the log of early-life PM2.5 exposure, both overall and separated by type, and the odds of neonatal and infant mortality, adjusting for child-level, parent-level and household-level characteristics. Results We find little evidence that early-life exposure to overall PM2.5 is associated with higher odds of mortality relative to low exposure to PM2.5. However, about half of PM2.5 is naturally occurring dust and sea-salt whereas half is from other sources, comprising mainly carbon-based compounds, which are mostly due to human activity. We find a very strong association between exposure to carbonaceous PM2.5 and infant mortality, particularly neonatal mortality, i.e. mortality in the first 28 days after birth. We estimate that, at the mean level of exposure in the sample to carbonaceous PM2.5—10.9 µg/m3—the odds of neonatal mortality are over 50% higher than in the absence of pollution. Conclusion Our results suggest that the current World Health Organization guideline of limiting the overall ambient PM2.5 level to less than 10 µg/m³ should be augmented with a lower limit for harmful carbonaceous PM2.5.

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Exposure to air pollution and tobacco smoking and their combined effects on depression in six low- and middle-income countries

The British Journal of Psychiatry ◽

10.1192/bjp.bp.117.202325 ◽

2017 ◽

Vol 211 (3) ◽

pp. 157-162 ◽

Cited By ~ 26

Author(s):

Hualiang Lin ◽

Yanfei Guo ◽

Paul Kowal ◽

Collins O. Airhihenbuwa ◽

Qian Di ◽

...

Keyword(s):

Air Pollution ◽

Logistic Regression ◽

Tobacco Smoking ◽

Smoking Status ◽

Fine Particulate Matter ◽

Additive Model ◽

Interactive Effects ◽

Middle Income ◽

Middle Income Countries ◽

Low And Middle Income

BackgroundLittle is known about the joint mental health effects of air pollution and tobacco smoking in low- and middle-income countries.AimsTo investigate the effects of exposure to ambient fine particulate matter pollution (PM2.5) and smoking and their combined (interactive) effects on depression.MethodMultilevel logistic regression analysis of baseline data of a prospective cohort study (n=41785). The 3-year average concentrations of PM2.5 were estimated using US National Aeronautics and Space Administration satellite data, and depression was diagnosed using a standardised questionnaire. Three-level logistic regression models were applied to examine the associations with depression.ResultsThe odds ratio (OR) for depression was 1.09 (95% CI 1.01–1.17) per 10 μg/m3 increase in ambient PM2.5, and the association remained after adjusting for potential confounding factors (adjusted OR = 1.10, 95% CI 1.02–1.19). Tobacco smoking (smoking status, frequency, duration and amount) was also significantly associated with depression. There appeared to be a synergistic interaction between ambient PM2.5 and smoking on depression in the additive model, but the interaction was not statistically significant in the multiplicative model.ConclusionsOur study suggests that exposure to ambient PM2.5 may increase the risk of depression, and smoking may enhance this effect.

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