Relationship between pulmonary function and indoor air pollution from coal combustion among adult residents in an inner-city area of southwest China

Effect of forceful suction and air disinfection machines on aerosol removal

BACKGROUNDS

Dental procedures involving drilling and grinding can produce a significant amount of suspended aerosol particles (PM) and bioaerosols. This study aims to analyze the size and concentration of aerosol particles generated during drilling and to investigate the effectiveness of two air exchange systems, namely forceful suction (FS) and air disinfection machines (DM), in removing PM.

METHODS

For this study, 100 extracted permanent teeth were collected and divided into three groups: without suction (n = 50), suction with forceful suction (n = 25), and suction with air disinfection machines (n = 25). The removal rate of suspended aerosol particles was analyzed using particle counters and air data multimeter.

RESULTS

When drilling and grinding were performed without vacuum, 0.75% of the aerosol particles generated were PM2.5-10, 78.25% of total suspended aerosol particles (TSP) were PM2.5, and 98.68% of TSP were PM1. The nanoanalyzer measurements revealed that the aerodynamic diameter of most aerosol particles was below 60 nm, with an average particle diameter of 52.61 nm and an average concentration of 2.6*1011 ultrafine aerosol particles. The air change per hour (ACH) was significantly lower in the air disinfection machines group compared to the forceful suction group. Additionally, the number of aerosol particles and mass concentration was significantly lower in the air disinfection machines group compared to the forceful suction group in terms of PM2.5 levels. However, the forceful suction group also reduced the mass concentration in PM10 level than the air disinfection machines group.

CONCLUSION

In conclusion, the air exchange system can reduce the aerosol particles generated during drilling and grinding. Comparing the two air exchange systems, it was found that the air disinfection machines group reduces the number of aerosol particles and mass concentration in PM2.5 levels, while the forceful suction group reduces the mass concentration in PM10 level.

Lung function among residents from the largest coal region in Brazil

Coal mining and burning activities in coal-fired power plants are among the most polluting activities in developing countries. In Brazil, the Candiota coal deposit concentrates 40% of the national mineral coal. Although, previous studies indicate several negative health outcomes to residents of this coal region, there is no information about lung function. Thus, this study aimed to evaluate lung function by spirometry among residents from the largest coal mining region of Brazil and its related factors. It was carried out a cross-sectional study with 300 male adults residing in four cities from this region. Socioeconomic, demographic, life style, and health conditions were collected through a structured questionnaire, and lung function was assessed by spirometry. Almost 18% of the residents have disorders in pulmonary function. There was significant statistical difference in the spirometry main parameters between the cities. Candiota city (host city of coal exploration activities) have the highest prevalence of obstructive ventilatory disorder. Curiously, upper economic class had significant higher risk of altered lung function (P<0.001), as well as inappropriate sewage destination (P<0.001). Residents of Candiota city had 20% higher risk of altered lung function. Regarding air quality, the PM₁₀, SO₂, and NO₂ of the region were 20.6± 3.9, 7.0± 2.2, and 6.0± 1.6, respectively. Two air quality stations exceed the limit of 20 μg/m³ to PM₁₀ proposed by Brazilian legislation and WHO, and three stations had PM₁₀ quite close to the limit. This study points out the need for urgent action to protect residents from this coal mining region.

Association of long-term indoor exposure to fine particles with pulmonary effects in Northern Taiwan

An association between short-term indoor exposure to fine particles (PM_2.5) and acute respiratory effects has been reported. It is still unclear whether long-term indoor exposure to PM_2.5 is associated with pulmonary events. This study recruited 1023 healthy adult homeworkers to conduct a prospective observational study from 2010 to 2021. Four repeated home visits per year were conducted for each participant to measure 24-hour PM_2.5 and peak expiratory flow rate (PEFR) and to collect blood samples for absolute eosinophil count (AEC) and carcinoembryonic antigen (CEA) analysis. Additionally, a questionnaire related to personal characteristics, health status and home characteristics was conducted for each participant. The mixed-effects models showed a significant association of PM_2.5 with increased CEA and AEC and decreased % predicted PEFR. No significant association between low-level PM_2.5 exposure (10-year mean level < 10 μg/m³) and adverse pulmonary effects was observed. The present study concluded that long-term indoor exposure to PM_2.5 at a concentration higher than 10 μg/m³ was associated with adverse pulmonary effects among healthy adult homeworkers.

A comparative analysis of biomass and clean fuel exposure on pulmonary function during cooking among rural women in Tamilnadu, India

It is of interest to document data on the comparative analysis of biomass and clean fuel exposure on pulmonary function during cooking among rural women. The study consisted of 100 biomass and 100 LPG fuel using women with no smoking habits and other related illness Parameters such as FVC, FEV1, FEV1/FVC, PEFR, FEF25-75%were obtained using the computerized spirometry to assess the pulmonary function in these subjects. The collected data were analyzed using the Student t-test method and Pearson correlation. The exposure index for biomass fuel users is 69.78±27.25 showing high exposure duration during cooking. The parameters for pulmonary functions significantly declined in FVC (42.34±13.6), FEV1 (45.55±15.98), PEFR (34.11±14.78) and FEF25-75% (45.56±23.00) for biomass fuel user. However, this is not true for FEV1/FVC ratio (107.56±16.9). The increase in PFT suggests the restrictive and obstructive patterns of pulmonary diseases. There was a negative correlation between increased duration of cooking and the value of FEV1/FVC (r = -0.2961), FEF25-75% (r = -0.3519) and PEFR (r = -0.2868). Thus, the deformation of pulmonary function due to extended exposure of biomass fuel for cooking women in rural Tamilnadu is shown using parameter features such as high exposure index, overcrowded area and improper ventilated houses.

Concentrations, sizes distributions, and seasonal variations of ambient air pollutants (particulates, trace metals) in Daya/Xitun District, Taichung, Central Taiwan: a case study at Taichung Science Park

Taichung Science Park in central Taiwan releases ambient air pollutants to the atmosphere. This issue has attracted much attention over the past few years. This study concerns seasonal concentrations of atmospheric particles and metallic elements and particle size distributions. A M.O.U.D.I sampler is used at a Taichung Science Park sampling site to obtain relevant data. Fe, followed by Al, had the highest average metallic element concentrations in particles of various sizes (PM₁₈, PM₁₀, PM_2.5, PM₁ and PM_<1(0.3)); Cd had the lowest. The average concentrations of metallic elements in particles of various sizes were lowest in the summer. Fe, Al and Cr had the three highest concentrations among all metallic elements for all particles sizes in all seasons. Ambient air particulate pollutants (crustal and anthropogenic metallic elements) were released from a single emission source at Taichung Science Park site.

Household solid fuel use and peak expiratory flow in middle-aged and older adults in China: A large cohort study (2011-2015)

Indoor air pollution caused by solid fuel use in cooking and heating in China is common. The relationship between household solid fuel use and peak expiratory flow (PEF) in middle-aged and older adults in China has not been clarified. The aim of this study was to assess the relationship between long-term household solid fuel use (clean for both cooking and heating, solid for either cooking or heating, and solid for both cooking and heating) and PEF changes in middle-aged and older adults using a nationally representative prospective cohort. Covariance analysis was used to compare PEF changes in different indoor air pollution exposure groups. Separate analysis of cooking and heating as well as sub-group analyses by age, sex and smoking status were conducted, linear mixed growth model analysis was used to evaluate the association between cooking fuel type and PEF. A total of 6818 participants were enrolled in the cohort analysis. Results revealed that solid fuel use in cooking and heating separately or conjointly were associated with reduced PEF (solid fuel use in cooking: least square mean [LSM] = 19.9, 95% confidence interval [CI]: 11.5-28.2, P = 0.03; solid fuel use in heating: LSM = 19.4, 95% CI:11.2-27.5, P = 0.04; both solid fuel use: LSM = 17.6, 95% CI: 9.3-25.9, P for trend <0.0001), especially in participants aged >65 years (LSM = -9.22, 95% CI: 27.9-69.52, P for trend <0.0001), females (LSM = -6.41, 95% CI: 19.12-6.30, P for trend <0.0001) and current or former smokers (LSM = -21.55, 95% CI: 36.14 to -6.97, P < 0.02). Compared to that of participants using clean fuels for cooking, PEF of participants using solid fuels were decreased by 3.5 l/min per 2 years over a 4-year follow-up. This cohort study highlights the adverse effects of indoor air pollution on lung function in middle aged and older adults in China.

Correlation between indoor air pollution and adult respiratory health in Zunyi City in Southwest China: situation in two different seasons

BACKGROUND

Indoor environmental quality significantly influences the occurrence of asthma attack. Zunyi District has abundant coal reserves and is regarded as one of the cities that are most severely polluted by high levels of particulate matter in China. This study aimed to examine the correlation of indoor exposure with adult respiratory health, as well as the differences in effect between winter and summer.

METHODS

A cross-sectional epidemiological study was conducted among 1207 adult residents in Zunyi, Guizhou Province of Southwest China in winter and summer. Data on health variables related to asthma and home environmental factors were collected using a modified European Community Respiratory Health Survey II questionnaire. The following data were obtained: samples of particulate matter 2.5 (PM2.5) inside and outside the households under study (n = 20); lung function status, including peak expiratory flow rate, forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1), and FEV1/FVC ratio.

RESULT

The odds ratio (OR) for asthma-like symptoms and asthma in adults using coal stove for cooking or warming, relative to non-users, was 1.73 (95% CI, 1.11-2.69) in winter vs. 1.30 (95% CI, 0.79-2.14) in summer. Adult residents with exposure to cooking oil fumes were at a considerably higher risk of asthma-like symptoms and asthma [OR = 2.65 (95% CI, 1.25 to 5.61) in winter vs. OR = 7.93 (95% CI, 2.54 to 24.75] in summer] than those without such exposure. The prevalence of asthma-like symptoms and asthma was significantly higher in adults with high kitchen risk scores or high sleeping-area risk scores than in those with low scores in both seasons (p < 0.05). The relative kitchen and sleeping area PM2.5 concentrations were higher in winter than in summer (p < 0.05). Lung function was negatively associated with indoor kitchen and sleeping area relative PM2.5 concentration in winter rather than summer (p < 0.001). The effect of exposure to indoor risk factors on lung function among the residents was greater in winter than in summer (p < 0.001).

CONCLUSION

Exposure to indoor risk factors, such as aerocontaminants from coal combustion, causes asthma symptoms and reduces pulmonary function. The effect of indoor risk factors on respiratory health among adults with such exposure was greater in winter than in summer.

Indoor PM2.5 from coal combustion aggravates ovalbumin-induced asthma-like airway inflammation in BALB/c mice

We hypothesized that indoor PM_2.5 exposure from coal combustion exaggerates airway inflammation in the lung tissue of asthmatic mice induced with ovalbumin (OVA). Forty BALB/c mice, randomly divided into four groups (n = 10 per group), were intratracheally instilled with normal saline alone, PM_2.5 (2.5 mg/ml PM_2.5 alone), OVA (15 μg/ml OVA alone), and PM_2.5+OVA (2.5 mg/ml PM_2.5 and 15 μg/ml OVA), respectively, four times at 2-wk intervals. Daily mean concentration of PM_2.5 from indoor coal combustion was 156.95 μg/m³. The highest metal composition in PM_2.5 was Zn (34.81 ± 1.8 μg/m³). Exposure to PM_2.5+OVA significantly elevated IL-4 and decreased IFN-γ production in mice compared with the control (P < 0.05). Exposure to PM_2.5+OVA showed a significant increase in the protein levels of granulocyte-macrophage colony-stimulating factor and IL-8 and a decrease in the protein level of transforming growth factor-β1 in bronchoalveolar lavage fluid of mice compared with the control (P < 0.05). The expression of IL-4 mRNA was significantly increased, whereas the expression of IFN-γ mRNA was decreased in lung tissue of the PM_2.5+OVA group (P < 0.05). The expression level of Foxp3 mRNA in the PM_2.5+OVA group was significantly lower than that in the control group in lung tissue (P < 0.05). Treatment with PM_2.5+OVA promoted a prominent neutrophil sequestration into the lung parenchyma, goblet cell proliferation, and severe inflammatory cell infiltration in the airways. Exposure to PM_2.5 from indoor coal combustion might induce airway inflammatory immune responses and exacerbate peribronchiolar inflammation due to infiltration of inflammatory cells into the airway submucosa and airway structural pathological changes.

Effects of indoor coal fine particulate matter on the expression levels of inflammatory factors in ovalbumin-induced mice

Objective: Cooking and heating with coal is the main source of household air pollution in acid rain-plagued areas of China and is a leading contributor to disease burden. In this study, we investigated the adverse effects of exposure to indoor fine particulate matter emission from coal combustion on the expression levels of inflammatory factors in ovalbumin (OVA)-induced mice. Methods: Forty BALB/c male mice were randomly divided into four groups (control group, PM2.5 group, OVA group, and OVA + PM2.5 group; n = 10) and treated with ovalbumin (OVA) or PM2.5, alone or together. Interleukin-4 (IL-4), interleukin-7 (IL-7), interleukin-8 (IL-8), interleukin-17 (IL-17), transforming growth factor β1 (TGF-β1), and interferon γ (IFN-γ) protein expression levels were measured in bronchoalveolar lavage fluid (BALF). Additionally, serum immunoglobulin (Ig) IgE and IgG1 levels were measured. The mRNA expression levels of IL-7 and IFN-γ in pulmonary tissue were also analyzed. Bronchoalveolar lavage (BAL), inflammatory cell counts, and histopathological examinations were also performed. Results: Exposure to PM2.5 + OVA induced abnormal pathological changes and inflammatory responses in lungs compared to the control. The levels of IL-4, IL-7, IL-8 and IL-17 in BALF from the OVA + PM2.5 group were higher than those in BALF from the control group, OVA group, and PM2.5 group (P < 0.05). PM2.5 plus OVA significantly raised the serum IgE and IgG1 levels compared with the control group. An increasing IL-7 mRNA trend was found among the treatment groups (P < 0.05). The expression level of IFN-γ mRNA was significantly higher in the control group than in the other 3 groups (P < 0.05). Conclusion: Indoor coal PM2.5 was sufficient by itself to cause inflammatory cellular infiltration of pulmonary tissue, leading to organelle injury and physiological structure change. Additionally, it promoted the occurrence and development of asthma by influencing the expression levels of IL-7 and various relevant inflammatory factors (such as IL-4 and IL-8) and changing the equilibrium between Treg and Th17 cells.

Particulate matter air pollution and respiratory impact on humans and animals

Air pollution is now fully acknowledged to be a public health problem and a social issue. Particulate matter (PM) concentration has been linked with several clinical manifestations of pulmonary and cardiovascular diseases and is associated with morbidity and mortality induced by respiratory diseases both in human and animals. Current research on airborne particle-induced health effects investigates the critical characteristics of particulate matter that determine their biological effects. Scientific evidence assessed that the size of the airborne particles and their surface area determine the potential to elicit inflammatory injury, oxidative damage, and other biological effects. Thus, the present review paper aims to summarize the current evidences and findings on the effect of air pollution on lung function in both humans and animals.

Air pollutants and asthma patient visits: Indication of source influence

BACKGROUND

Sources of air pollutants are significant factors for adverse health effect. Few current studies explored the linking of sources influence and ambient pollutants to asthma patient visits in Shanghai, China.

OBJECTIVES

This study explored the associations between short-term exposures to ambient pollutants and asthma morbidity with terrestrial and marine source influence in Shanghai.

METHODS

Generalized additive model (GAM) was used to explore the association of daily patient visits and ambient pollutants. These analyses were calculated in R statistical software in mgcv package. PSCF modeling was used to locate potential source areas contributing to the concentrations of pollutants.

RESULTS

We found that per IQR of PM_2.5, PM₁₀, NO₂, SO₂, O₃ and CO in terrestrial source were associated with an increase of 6.63% (95% CI: -0.27% to 14%), 6.48% (95% CI: 0.06% to 13.3%), 1.68% (95% CI: -2.68% to 6.24%), 2.81% (95% CI: -1.42% to 7.22%), -0.60% (95% CI: -5.94% to 5.04%) and 16.6% (95% CI: 8.68% to 25.2%), respectively in asthma patient visits. Per IQR of PM_2.5, PM₁₀, NO₂, SO₂, O₃ and CO in marine source were associated with an increase of 5.34% (95% CI: 0.42% to 10.5%), 3.84% (95% CI: 0.08% to 7.74%), 3.21% (95% CI: -0.92% to 7.52%), 2.58% (95% CI: -1.02% to 6.30%), 1.42% (95% CI: -3.10% to 6.15%) and 8.81% (95% CI: 2.56% to 15.4%). The PSCF show all of the pollutants except O₃ mainly come from terrestrial during observation. We also found that all of the pollutants except NO₂ displayed the highest effect in the spring for relative risk of asthma morbidity.

CONCLUSIONS

Ambient air pollutants that cause an increase in asthma patient visits, such as PM_2.5, PM₁₀, NO₂, SO₂ and CO are mainly produced from terrestrial sources, while O₃ is primarily from marine sources. The association of ambient pollutants and asthma patient visits is closely related with seasons, especially with spring. PM_2.5 and CO are major air pollutants increasing the relative risk of asthma patient visits in Shanghai.

Coal combustion related fine particulate matter (PM2.5) induces toxicity in Caenorhabditis elegans by dysregulating microRNA expression

We employed an in vivo assay system of Caenorhabditis elegans to determine if and which microRNAs (miRNAs) were dysregulated upon exposure to coal combustion related fine particulate matter (PM2.5) by profiling the miRNAs using SOLiD sequencing. From this, expression of 25 miRNAs was discovered to become dysregulated by exposure to PM2.5. Using the corresponding C. elegans deletion mutants, 5 miRNAs (mir-231, mir-232, mir-230, mir-251 and mir-35) were found to be involved in the control of PM2.5 toxicity. Furthermore, mutation of mir-231 or mir-232 induced a resistance to PM2.5 toxicity, whereas mutation of mir-230, mir-251, or mir-35 induced a susceptibility to PM2.5 toxicity. SMK-1, an ortholog of the mammalian SMEK protein, was identified as a molecular target for mir-231 in the regulation of PM2.5 toxicity. In addition, the genes of sod-3, sod-4 and ctl-3, which are necessary for protection against oxidative stress, were determined to be important downstream targets of smk-1 in the regulation of PM2.5 toxicity. The triggering of this mir-231-SMK-1-SOD-3/SOD-4/CTL-3 signaling pathway may be a critical molecular basis for the role of oxidative stress in the induction of coal combustion related PM2.5 toxicity.

Indoor environmental factors associated with pulmonary function among adults in an acid rain-plagued city in Southwest China

OBJECTIVE

To assess the association of indoor environmental risk factors with respiratory function among adults in an acid rain-plagued city in China where coal use is frequent.

METHODS

The subjects were randomly selected in the winter season. Information on selected home environmental factors was collected through administered questionnaires. Additionally, pulmonary function tests, including Forced Vital Capacity (FVC), Forced Expiratory Volume in 1 s (FEV₁), FEV₁/FVC and Peak Expiratory Flow Rate (PEFR) were also performed in participants.

RESULTS

This study showed that, among a variety of risk factors, coal fuel use, cooking oil fumes and active and passive smoking exposure together with asthma in childhood were important factors for deterioration of pulmonary function among adults in the winter season (p < 0.05). Additionally, subjects whose kitchen was located in the living room or bedroom, who opened their windows only occasionally or never, who noted the presence of cooking oil fumes and pests, whose bedroom was shared by 3 or more residents and who kept pets tended to exhibit lower values of FVC, FEV₁ and PEFR values compared with non-exposed counterparts (p < 0.05).

CONCLUSIONS

This study demonstrated impaired pulmonary function among adults who were exposed to indoor risk factors, such as coal fires and cigarette smoking compared to non-users in the winter season and emphasizes the need for public health efforts to decrease exposure to indoor air pollution.

Indoor Environmental Factors and Occurrence of Lung Function Decline in Adult Residents in Summer in Southwest China

BACKGROUND

There is conflicting reports on the respiratory health effects of indoor risk factor exposure. The aim of this study was to assess the association of indoor environmental factors to pulmonary function in an adult population in Zunyi City of Southwest China.

METHODS

Between July and Sep 2012, we conducted a cross-sectional survey of people aged ≥18 yr in 11 inner-city areas of Zunyi. Data on asthma and asthma-related symptoms and selected home environmental factors were assessed by questionnaire. Lung function measurements, including FVC, FEV₁, FEV₁/FVC and PEFR, were assessed and compared. Exposure to indoor and outdoor PM_2.5 was monitored by measurement of PM_2.5 emission relative concentration.

RESULTS

Cooking oil fumes, environmental tobacco smoke (ETS) and coal fuel use were associated with impaired lung function among adults in summer season (P<0.05). Subjects exposed coal fuel combustion, cooking oil fumes, pest in kitchen, mosquito repellent, fluffy blanket, pets, visible mold in bedroom and ETS (active and passive smoking) tended to exhibit greater decreases in FVC, FEV₁ and PEFR values compared with their non-exposed counterparts (P<0.05). Median PM_2.5 relative concentrations in kitchen, sleeping area and outdoor were 486.0cpm, 463.0cpm and 459.0cpm, respectively. PM_2.5 relative concentration in indoor kitchen and sleeping area were significant higher than outdoor (P<0.001).

CONCLUSION

A negative association between kitchen, sleeping area risk factors and ETS exposure and a reduction in lung function in summer was revealed in Zunyi.

Fuel for Life: Domestic Cooking Fuels and Women's Health in Rural China

BACKGROUND

There is evidence that household air pollution is associated with poor health in China, and that this form of air pollution may even be more of a health concern in China than the much-publicized outdoor air pollution. However, there is little empirical evidence on the relationship between household air pollution and health in China based on nationally representative and longitudinal data. This study examines the association between the type of domestic cooking fuel and the health of women aged ≥16 in rural China.

METHODS

Using longitudinal and biomarker data from the China Family Panel Studies (n = 12,901) and the China Health and Nutrition Survey (n = 15,539), we investigate the impact of three major domestic cooking fuels (wood/straw, coal, liquefied petroleum gas (LPG)) on health status using both cross-sectional and panel approaches.

RESULTS

Compared to women whose households cook with dirty fuels like wood/straw, women whose households cook with cleaner fuels like LPG have a significantly lower probability of chronic or acute diseases and are more likely to report better health. Cooking with domestic coal instead of wood or straw is also associated with elevated levels of having certain risks (such as systolic blood pressure) related to cardiovascular diseases.

CONCLUSIONS

Our study provides evidence that using cleaner fuels like LPG is associated with better health among women in rural China, suggesting that the shift from dirty fuels to cleaner choices may be associated with improved health outcomes.

Contribution of heavy metals to toxicity of coal combustion related fine particulate matter (PM2.5) in Caenorhabditis elegans with wild-type or susceptible genetic background

Contribution of chemical components in coal combustion related fine particulate matter (PM2.5) to its toxicity is largely unclear. We focused on heavy metals in PM2.5 to investigate their contribution to toxicity formation in Caenorhabditis elegans. Among 8 heavy metals examined (Fe, Zn, Pb, As, Cd, Cr, Cu, and Ni), Pb, Cr, and Cu potentially contributed to PM2.5 toxicity in wild-type nematodes. Combinational exposure to any two of these three heavy metals caused higher toxicity than exposure to Pb, Cr, or Cu alone. Toxicity from the combinational exposure to Pb, Cr, and Cu at the examined concentrations was higher than exposure to PM2.5 (100 mg/L). Moreover, mutation of sod-2 or sod-3 gene encoding Mn-SOD increased susceptibility in nematodes exposed to Fe, Zn, or Ni, although Fe, Zn, or Ni at the examined concentration did not lead to toxicity in wild-type nematodes. Our results highlight the potential contribution of heavy metals to PM2.5 toxicity in environmental organisms.

Aeroparticles, Composition, and Lung Diseases

Urban air pollution is a serious worldwide problem due to its impact on human health. In the past 60 years, growing evidence established a correlation between exposure to air pollutants and the developing of severe respiratory diseases. Recently particulate matter (PM) is drawing more public attention to various aspects including historical backgrounds, physicochemical characteristics, and its pathological role. Therefore, this review is focused on these aspects. The most famous air pollution disaster happened in London on December 1952; it has been calculated that more than 4,000 deaths occurred during this event. Air pollution is a complex mix of gases and particles. Gaseous pollutants disseminate deeply into the alveoli, allowing its diffusion through the blood–air barrier to several organs. Meanwhile, PM is a mix of solid or liquid particles suspended in the air. PM is deposited at different levels of the respiratory tract, depending on its size: coarse particles (PM₁₀) in upper airways and fine particles (PM_2.5) can be accumulated in the lung parenchyma, inducing several respiratory diseases. Additionally to size, the composition of PM has been associated with different toxicological outcomes on clinical and epidemiological, as well as in vivo and in vitro animal and human studies. PM can be constituted by organic, inorganic, and biological compounds. All these compounds are capable of modifying several biological activities, including alterations in cytokine production, coagulation factors balance, pulmonary function, respiratory symptoms, and cardiac function. It can also generate different modifications during its passage through the airways, like inflammatory cells recruitment, with the release of cytokines and reactive oxygen species (ROS). These inflammatory mediators can activate different pathways, such as MAP kinases, NF-κB, and Stat-1, or induce DNA adducts. All these alterations can mediate obstructive or restrictive respiratory diseases like asthma, COPD, pulmonary fibrosis, and even cancer. In 2013, outdoor air pollution was classified as Group 1 by IARC based on all research studies data about air pollution effects. Therefore, it is important to understand how PM composition can generate several pulmonary pathologies.

Occupational and environmental exposures and cancers in developing countries

BACKGROUND

Over the past few decades, there has been a decline in cancers attributable to environmental and occupational carcinogens of asbestos, arsenic, and indoor and outdoor air pollution in high-income countries. For low- to middle-income countries (LMICs), however, these exposures are likely to increase as industrialization expands and populations grow.

OBJECTIVE

The aim of this study was to review the evidence on the cancer risks and burdens of selected environmental and occupational exposures in less-developed economies.

FINDINGS

A causal association has been established between asbestos exposure and mesothelioma and lung cancer. For arsenic exposure, there is strong evidence of bladder, skin, lung, liver, and kidney cancer effects. Women are at the highest risk for lung cancer due to indoor air pollution exposure; however, the carcinogenic effect on the risk for cancer in children has not been studied in these countries. Cancer risks associated with ambient air pollution remain the least studied in LMICs, although reported exposures are higher than World Health Organization, European, and US standards. Although some associations between lung cancer and ambient air pollutants have been reported, studies in LMICs are weak or subject to exposure misclassification. For pulmonary cancers, tobacco smoking and respiratory diseases have a positive synergistic effect on cancer risks.

CONCLUSIONS

A precise quantification of the burden of human cancer attributable to environmental and occupational exposures in LMICs is uncertain. Although the prevalence of carcinogenic exposures has been reported to be high in many such countries, the effects of the exposures have not been studied due to varying country-specific limitations, some of which include lack of resources and government support.

Effect of Personal Exposure to PM2.5 on Respiratory Health in a Mexican Panel of Patients with COPD

Background: Air pollution is a problem, especially in developing countries. We examined the association between personal exposure to particulate matter with an aerodynamic diameter less than 2.5 µm (PM_2.5) on respiratory health in a group of adults with chronic obstructive pulmonary disease (COPD). Methods: All participants resided in Mexico City and during follow-up, personal exposure to PM_2.5, respiratory symptoms, medications, and daily activity were registered daily. Peak expiratory flow (PEF) was measured twice daily, from February through December, 2000, in 29 adults with moderate, severe, and very severe COPD. PEF changes were estimated for each 10 µg/m³ increment of PM_2.5, adjustment for severity of COPD, minimum temperature, and day of the sampling. Results: For a 10-µg/m³ increase in the daily average of a two-day personal exposure to PM_2.5, there was a significant 33% increase in cough (95% CI, range, 5‒69%), and 23% in phlegm (95% CI, range, 2‒54%), a reduction of the PEF average in the morning of −1.4 L/min. (95% CI , range, −2.8 to −0.04), and at night of −3.0 L/min (95% CI, range, −5.7 to −0.3), respectively. Conclusions: Exposure to PM_2.5 was associated with reductions in PEF and increased respiratory symptoms in adults with COPD. The PEF reduction was observed both at morning and at night.

Adverse effects of coal combustion related fine particulate matter (PM2.5) on nematode Caenorhabditis elegans

The toxic effects of coal combustion related fine particulate matter (PM2.5), collected from Datong, Shanxi province, China, on nematode Caenorhabditis elegans were investigated. Exposure to PM2.5 resulted in deficits in development, reproduction, locomotion behavior, and lifespan, and induction of intestinal autofluorescence or reactive oxygen species (ROS) production. Prolonged exposure to PM2.5 led to more severe toxicity on nematodes than acute exposure. In addition, exposure to PM2.5 induced altered expression patterns of genes required for the control of oxidative stress. Reduction in mean defecation cycle length and developmental deficits in AVL and DVB neurons, which are involved in the control of defecation behavior, were also triggered by PM2.5 exposure. Thus, oxidative stress and abnormal defecation behavior may contribute greatly to the toxicity of coal combustion related PM2.5 in nematodes. The results also imply that the long-term adverse effects of coal combustion related PM2.5 on environmental organisms should be carefully considered.

MicroRNAs as regulators of airborne pollution-induced lung inflammation and carcinogenesis

The increasing incidence of pulmonary inflammation and lung cancer, as well as exacerbation of pre-existing chronic lung diseases by exposure to airborne pollutants, e.g., particulate matter and cigarette smoke, is becoming a major public health concern in the world. However, the exact mechanisms of pulmonary injury from exposure to these airborne insults have not been fully elucidated. Nevertheless, accumulating evidence suggests that microRNAs (miRNAs) may play a unique role in the regulation of airborne agent-induced lung inflammation and carcinogenesis. Since epigenetic modifications are heritable and reversible, this may provide a new insight into the relationship of miRNAs and environmental pollution-related lung disorders. The aim of this review was to update our existing knowledge regarding the mechanisms by which airborne pollutants altering miRNA profiles in the lung, specifically for cigarette smoke and airborne particulate matter, and the potential biological roles of miRNAs in the initiation of pulmonary inflammation and lung cancer, as well as the regulation of underlying genetic susceptibility to these environmental stressors.