PM2.5 in Beijing - temporal pattern and its association with influenza

The Impact of PM2.5 on the Host Defense of Respiratory System

The harm of fine particulate matter (PM_2.5) to public health is the focus of attention around the world. The Global Burden of Disease (GBD) Study 2015 (GBD 2015 Risk Factors Collaborators, 2016) ranked PM_2.5 as the fifth leading risk factor for death, which caused 4.2 million deaths and 103.1 million disability-adjusted life-years (DALYs) loss, representing 7.6% of total global deaths and 4.2% of global DALYs. Epidemiological studies have confirmed that exposure to PM_2.5 increases the incidence and mortality of respiratory infections. The host defense dysfunction caused by PM_2.5 exposure may be the key to the susceptibility of respiratory system infection. Thus, this review aims to assess the impact of PM_2.5 on the host defense of respiratory system. Firstly, we elaborated the epidemiological evidence that exposure to PM_2.5 increases the risk of respiratory infections. Secondly, we summarized the experimental evidence that PM_2.5 exposure increases the susceptibility of different pathogens (including bacteria and viruses) in respiratory system. Furthermore, here we discussed the underlying host defense mechanisms by which PM_2.5 exposure increases the risk of respiratory infections as well as future perspectives.

Effect of the wetland environment on particulate matter and dry deposition

In Beijing, particulate matter (PM) in the atmosphere, especially PM_2.5 and PM₁₀, have attracted public attention because of its adverse effects. A series of studies have investigated the sources and spatial-temporal variation of PM. Wetland has been reported to own the capacity of resolving air problem. To examine the characteristics of the particulate matter in wetlands, the diurnal variation of PM_2.5 and PM₁₀ concentrations with respect to two heights (i.e. 1.5 and 10 m, respectively) and three meteorological factors (i.e. wind speed, temperature, and relative humidity, respectively) was monitored in the Cuihu National Wetland Park in Beijing, and the dry deposition velocity and flux were analysed using the above-mentioned data. Results indicated that (1) As for diurnal variation, the PM concentration constantly decreased at 07:00-16:00 and gradually increased at 16:00-18:00. The maximum instantaneous concentration was observed at 07:00-10:00, while the minimum instantaneous concentration was observed at 13:00-16:00. (2) The annual concentration variation of PM followed the order of dry period > wet period > normal period. (3) The particulate concentrations at 10 m were always greater than those at 1.5 m. (4) The PM concentration was positively correlated to the relative humidity and negatively correlated to the temperature. Wind speed exhibited a complex effect on PM concentration. (5) The regulation of dry deposition efficiency followed the order of spring > winter > summer. (6) Wind speed strongly and positively affected the dry deposition velocity of PM10. The effects of temperature and relative humidity on dry deposition were uncertain.

Particulate Matter 2.5 Causes Deficiency in Barrier Integrity in Human Nasal Epithelial Cells

Purpose

The effect of air pollution-related particulate matter (PM) on epithelial barrier function and tight junction (TJ) expression in human nasal mucosa has not been studied to date. This study therefore aimed to assess the direct impact of PM with an aerodynamic diameter less than 2.5 μm (PM2.5) on the barrier function and TJ molecular expression of human nasal epithelial cells.

Methods

Air-liquid interface cultures were established with epithelial cells derived from noninflammatory nasal mucosal tissue collected from patients undergoing paranasal sinus surgery. Confluent cultures were exposed to 50 or 100 µg/mL PM2.5 for up to 72 hours, and assessed for 1) epithelial barrier integrity as measured by transepithelial resistance (TER) and permeability of fluorescein isothiocyanate (FITC) 4 kDa; 2) expression of TJs using real-time quantitative polymerase chain reaction and immunofluorescence staining, and 3) proinflammatory cytokines by luminometric bead array or enzyme-linked immunosorbent assay.

Results

Compared to control medium, 50 and/or 100 µg/mL PM2.5-treatment 1) significantly decreased TER and increased FITC permeability, which could not be restored by budesonide pretreatment; 2) significantly decreased the expression of claudin-1 messenger RNA, claudin-1, occludin and ZO-1 protein; and 3) significantly increased production of the cytokines interleukin-8, TIMP metallopeptidase inhibitor 1 and thymic stromal lymphopoietin.

Conclusions

Exposure to PM2.5 may lead to loss of barrier function in human nasal epithelium through decreased expression of TJ proteins and increased release of proinflammatory cytokines. These results suggest an important mechanism of susceptibility to rhinitis and rhinosinusitis in highly PM2.5-polluted areas.

Effects of temperature, humidity, and diurnal temperature range on influenza incidence in a temperate region

Background

The effect of temperature and humidity on the incidence of influenza may differ by climate region. In addition, the effect of diurnal temperature range on influenza incidence is unclear, according to previous study findings.

Objectives

The aim of this study was to analyze the effects of temperature, humidity, and diurnal temperature range on the incidence of influenza in Seoul, Republic of Korea, which is located in a temperate region.

Methods

We used Korean National Health insurance data to assess the weekly influenza incidence between 2010 and 2016, and used meteorological data from Seoul. To investigate the effect of temperature, relative humidity, and diurnal temperature range levels on influenza incidence, we used a distributed lag non‐linear model.

Results

The risk of influenza incidence was significantly increased with low daily temperatures of 0‐5°C and low (30%–40%) or high (70%) relative humidity. We found a positive significant association between diurnal temperature range and influenza incidence in this study.

Conclusions

Influenza incidence increased with low temperature and low/high humidity in a temperate region. Influenza incidence also increased with high diurnal temperature range, after considering temperature and humidity.

The short-term effects of air pollutants on influenza-like illness in Jinan, China

Background

There is valid evidence that air pollution is associated with respiratory disease. However, few studies have quantified the short-term effects of six air pollutants on influenza-like illness (ILI). This study explores the potential relationship between air pollutants and ILI in Jinan, China.

Methods

Daily data on the concentration of particulate matters < 2.5 μm (PM 2.5), particulate matters < 10 μm (PM10), sulfur dioxide (SO₂), nitrogen dioxide (NO₂), carbon monoxide (CO), and ozone (O₃) and ILI counts from 2016 to 2017 were retrieved. The wavelet coherence analysis and generalized poisson additive regression model were employed to qualify the relationship between air pollutants and ILI risk. The effects of air pollutants on different age groups were investigated.

Results

A total of 81,459 ILI counts were collected, and the average concentrations of PM2.5, PM10, O₃, CO, SO₂ and NO₂ were 67.8 μg/m³, 131.76 μg/ m³, 109.85 μg/ m³, 1133 μg/ m³, 33.06 μg/ m³ and 44.38 μg/ m³, respectively. A 10 μg/ m³ increase in concentration of PM2.5, PM10, CO at lag0 and SO₂ at lag01, was positively associated with a 1.0137 (95% confidence interval (CI): 1.0083–1.0192), 1.0074 (95% CI: 1.0041–1.0107), 1.0288 (95% CI: 1.0127–1.0451), and 1.0008 (95% CI: 1.0003–1.0012) of the relative risk (RR) of ILI, respectively. While, O3 (lag5) was negatively associated with ILI (RR 0.9863; 95%CI: 0.9787–0.9939), and no significant association was observed with NO₂, which can increase the incidence of ILI in the two-pollutant model. A short-term delayed impact of PM2.5, PM10, SO2 at lag02 and CO, O3 at lag05 was also observed. People aged 25–59, 5–14 and 0–4 were found to be significantly susceptible to PM2.5, PM10, CO; and all age groups were significantly susceptible to SO₂; People aged ≥60 year, 5–14 and 0–4 were found to be significantly negative associations with O₃.

Conclusion

Air pollutants, especially PM2.5, PM10, CO and SO₂, can increase the risk of ILI in Jinan. The government should create regulatory policies to reduce the level of air pollutants and remind people to practice preventative and control measures to decrease the incidence of ILI on pollution days.

Potential effect of germanium exposure on the risk of influenza-like illness in housewives in Shanxi Province, China

Few studies have examined the relationship between exposure to germanium (Ge) and the risk of influenza-like illness (ILI). Therefore, we investigated the association of Ge exposure and its interaction with single nucleotide polymorphisms (SNPs) related to Phase II metabolism on ILI risk among housewives in Shanxi Province, northern China. This cross-sectional study enrolled 373 housewives. Information on the housewives' characteristics and the frequency of ILI was collected by questionnaire. We analyzed the Ge concentrations in hair samples taken from near the scalp at the back of the head. Blood samples were used to identify SNPs related to Phase II metabolism. The results suggested that the hair Ge concentration was associated with ILI risk with an adjusted odds ratio and 95% confidence interval of 2.59 (1.61-4.19). A significant dose-response relationship was observed without or with adjusting for confounders. We did not observe any interaction effect between the hair Ge concentration and the SNPs on ILI risk. We found that high dietary consumption of meat and fried foods was positively correlated with the hair Ge concentration. Therefore, chronic Ge exposure may be a risk factor for an increased frequency of ILI in housewives.

Air pollution exposure associates with increased risk of neonatal jaundice

Clinical experience suggests increased incidences of neonatal jaundice when air quality worsens, yet no studies have quantified this relationship. Here we reports investigations in 25,782 newborns showing an increase in newborn's bilirubin levels, the indicator of neonatal jaundice risk, by 0.076 (95% CI: 0.027-0.125), 0.029 (0.014-0.044) and 0.009 (95% CI: 0.002-0.016) mg/dL per μg/m3 for PM2.5 exposure in the concentration ranges of 10-35, 35-75 and 75-200 μg/m3, respectively. The response is 0.094 (0.077-0.111) and 0.161 (0.07-0.252) mg/dL per μg/m3 for SO2 exposure at 10-15 and above 15 μg/m3, respectively, and 0.351 (0.314-0.388) mg/dL per mg/m3 for CO exposure. Bilirubin levels increase linearly with exposure time between 0 and 48 h. Positive relationship between maternal exposure and newborn bilirubin level is also quantitated. The jaundice-pollution relationship is not affected by top-of-atmosphere incident solar irradiance and atmospheric visibility. Improving air quality may therefore be key to lowering the neonatal jaundice risk.

Chemical and Biological Components of Urban Aerosols in Africa: Current Status and Knowledge Gaps

Aerosolized particulate matter (PM) is a complex mixture that has been recognized as the greatest cause of premature human mortality in low- and middle-income countries. Its toxicity arises largely from its chemical and biological components. These include polycyclic aromatic hydrocarbons (PAHs) and their nitro-derivatives (NPAHs) as well as microorganisms. In Africa, fossil fuel combustion and biomass burning in urban settings are the major sources of human exposure to PM, yet data on the role of aerosols in disease association in Africa remains scarce. This review is the first to examine studies conducted in Africa on both PAHs/NPAHs and airborne microorganisms associated with PM. These studies demonstrate that PM exposure in Africa exceeds World Health Organization (WHO) safety limits and carcinogenic PAHs/NPAHs and pathogenic microorganisms are the major components of PM aerosols. The health impacts of PAHs/NPAHs and airborne microbial loadings in PM are reviewed. This will be important for future epidemiological evaluations and may contribute to the development of effective management strategies to improve ambient air quality in the African continent.

A systematic literature review and critical appraisal of epidemiological studies on outdoor air pollution and tuberculosis outcomes

Ambient air pollution is the leading environmental risk factor for disease globally. Air pollutants can increase the risk of some respiratory infections, but their effects on tuberculosis (TB) are unclear. In this systematic literature review, we aimed to assess epidemiological studies on the association between outdoor air pollutants and TB incidence, hospital admissions and death (collectively referred to here as 'TB outcomes'). We sought to consolidate available evidence on this topic and propose recommendations for future studies. Following PRISMA guidelines, we searched PubMed, Web of Science, Google Scholar, and Scopus with no restrictions imposed on year of publication. A total of 11 epidemiological studies, performed in Asia, Europe and North America, met our inclusion criteria (combined sample size: 215,337 people). We extracted key study characteristics from each eligible publication, including design, exposure assessment, analytical approaches and effect estimates. The studies were assessed for overall quality and risk of bias using standard criteria. The pollutant most frequently associated with statistically significant effects on TB outcomes was fine particulate matter ( < 2.5 µm; PM_2.5); 6/11 studies assessed PM_2.5, of which 4/6 demonstrated a significant association). There was some evidence of significant associations between PM₁₀ ( < 10 µm), nitrogen dioxide (NO₂) and sulfur dioxide (SO₂) and TB outcomes, but these associations were inconsistent. The existing epidemiological evidence is limited and shows mixed results. However, it is plausible that exposure to air pollutants, particularly PM_2.5, may suppress important immune defence mechanisms, increasing an individual's susceptibility to development of active TB and TB-related mortality. Considering the small number of studies relative to the demonstrably large global health burdens of air pollution and TB, further research is required to corroborate the findings in the current literature. Based on a critical assessment of existing evidence, we conclude with methodological suggestions for future studies.

The effect of ambient temperature on the activity of influenza and influenza like illness in Jiangsu Province, China

OBJECTIVE

We aimed to evaluate and quantify the association between ambient temperature and activity of influenza like illness (ILI) and influenza in Jiangsu Province, China.

METHOD

Daily data of meteorology, influenza-like illness and detected influenza virus from 1 April 2013 to 27 March 2016 were collected. Distributed lag non-linear model (DLNM) was used to quantify the exposure-lag-response of ILI and influenza activity to daily average temperature.

RESULT

Influenza A virus (Flu-A) circulated throughout the year with two peaks at -4 °C and 28 °C respectively, while influenza B (Flu-B) viruses were usually tested positive in winter or early spring and peaked at 5 °C. The lag-response curves revealed that the RR of ILI increased with time and peaked 1 day later at low temperature (3 °C), however, the maximum RR of ILI caused by high temperature (26 °C) appeared immediately on day 0, the similar phenomena of immediate effect to ILI at high temperature were also observed in the lag-response curve for Flu-A or Flu-B.

CONCLUSION

ILI and Flu-A experienced two peaks of circulates at both low and high temperature in Jiangsu. The influenza viruses activity did drive up the rising of ILI%, particularly the activity of Flu-A which circulated throughout the year played a crucial role. Regional homogeneity was the relatively mainstream in aspects of cumulative association between influenza activity and temperature in Jiangsu Province.

Ambient PM2.5 Human Health Effects—Findings in China and Research Directions

Exposure to fine particulate matter (PM) results in adverse health outcomes. Although this is a global concern, residents of China may be particularly vulnerable due to frequent severe air pollution episodes associated with economic growth, industrialization, and urbanization. Until 2012, PM2.5 was not regulated and monitored in China and annual average concentrations far exceeded the World Health Organizations guidelines of 10 μg/m3. Since the establishment of PM2.5 Ambient Air Quality Criteria in 2012, concentrations have decreased, but still pose significant health risks. A review of ambient PM2.5 health effect studies is warranted to evaluate the current state of knowledge and to prioritize future research efforts. Our review found that recent literature has confirmed associations between PM2.5 exposure and total mortality, cardiovascular mortality, respiratory mortality, hypertension, lung cancer, influenza and other adverse health outcomes. Future studies should take a long-term approach to verify associations between exposure to PM2.5 and health effects. In order to obtain adequate exposure assessment at finer spatial resolutions, high density sampling, satellite remote sensing, or models should be employed. Personal monitoring should also be conducted to validate the use of outdoor concentrations as proxies for exposure. More research efforts should be devoted to seasonal patterns, sub-population susceptibility, and the mechanism by which exposure causes health effects. Submicron and ultrafine PM should also be monitored and regulated.

Stochastic Periodic Solution of a Susceptible-Infective Epidemic Model in a Polluted Environment under Environmental Fluctuation

It is well known that the pollution and environmental fluctuations may seriously affect the outbreak of infectious diseases (e.g., measles). Therefore, understanding the association between the periodic outbreak of an infectious disease and noise and pollution still needs further development. Here we consider a stochastic susceptible-infective (SI) epidemic model in a polluted environment, which incorporates both environmental fluctuations as well as pollution. First, the existence of the global positive solution is discussed. Thereafter, the sufficient conditions for the nontrivial stochastic periodic solution and the boundary periodic solution of disease extinction are derived, respectively. Numerical simulation is also conducted in order to support the theoretical results. Our study shows that (i) large intensity noise may help the control of periodic outbreak of infectious disease; (ii) pollution may significantly affect the peak level of infective population and cause adverse health effects on the exposed population. These results can help increase the understanding of periodic outbreak patterns of infectious diseases.

Estimating the Risk of Influenza-Like Illness Transmission Through Social Contacts: Web-Based Participatory Cohort Study

Background

Epidemiological studies on influenza have focused mostly on enhancing vaccination coverage or promoting personal hygiene behavior. Few studies have investigated potential effects of personal health behaviors and social contacts on the risk of getting influenza-like illness (ILI).

Objective

Taking advantage of an online participatory cohort, this study aimed to estimate the increased risk of getting ILI after contact with infected persons and examine how personal health behaviors, weather, and air pollution affect the probability of getting ILI.

Methods

A Web-based platform was designed for participants to record daily health behaviors and social contacts during the influenza season of October 1, 2015 to March 31, 2016, in Taiwan. Data on sleep, diet, physical activity, self-reported ILI, and contact with infected persons were retrieved from the diaries. Measurements of weather and air pollutants were used for calculating environmental exposure levels for the participants. We fitted a mixed-effects logistic regression model to the daily measurements of the diary keepers to estimate the effects of these variables on the risk of getting ILI.

Results

During the influenza season, 160 participants provided 14,317 health diaries and recorded 124,222 face-to-face contacts. The model estimated odds ratio of getting ILI was 1.87 (95% CI 1.40-2.50) when a person had contact with others having ILI in the previous 3 days. Longer duration of physical exercise and eating more fruits, beans, and dairy products were associated with lower risk of getting ILI. However, staying up late was linked to an elevated risk of getting ILI. Higher variation of ambient temperature and worse air quality were associated with increased risk of developing ILI.

Conclusions

Developing a healthier lifestyle, avoiding contact with persons having ILI symptoms, and staying alert with respect to temperature changes and air quality can reduce the risk of getting ILI.

Long-term exposure to PM2.5 lowers influenza virus resistance via down-regulating pulmonary macrophage Kdm6a and mediates histones modification in IL-6 and IFN-β promoter regions

Atmospheric particulates, especially PM2.5, not only damage the respiratory system, but also play important roles in pulmonary immunity. China is influenced by atmospheric diffusion conditions, industrial manufacturers, and heating and discharging. PM2.5 levels in the air rise substantially in the winter, which is also a period of flu high-incidence. Although an epidemiological link exists between PM2.5 and flu, we do not understand how long-term PM2.5 inhalation affects pulmonary immunity and the influenza virus response. Our study has prepared an in vivo PM2.5 mouse pharyngeal wall drop-in model and has found that PM2.5 exposure leads to mouse inflammatory injuries and furthers influenza A infection. Our results suggest that short-term exposure to PM2.5 significantly enhances the survival rate of influenza A-contaminated mice, while long-term PM2.5 inhalation lowers the capacity of pulmonary macrophages to secrete IL-6 and IFN-β. A disorder in the pulmonary innate defense system results in increased death rates following influenza infection. On a macromolecular level, this mechamism involves Kdm6a down-regulation after long-term exposure to PM 2.5 and a resultant increase in H3K4 and H3K9 methylation in IL-6 and IFN-β promoter regions. In summary, PM2.5 causes injuries of lung tissue cells and downregulates immune defense mechanisms in the lung.

Mitogenic stimulation accelerates influenza-induced mortality by increasing susceptibility of alveolar type II cells to infection

Development of pneumonia is the most lethal consequence of influenza, increasing mortality more than 50-fold compared with uncomplicated infection. The spread of viral infection from conducting airways to the alveolar epithelium is therefore a pivotal event in influenza pathogenesis. We found that mitogenic stimulation with keratinocyte growth factor (KGF) markedly accelerated mortality after infectious challenge with influenza A virus (IAV). Coadministration of KGF with IAV markedly accelerated the spread of viral infection from the airways to alveoli compared with challenge with IAV alone, based on spatial and temporal analyses of viral nucleoprotein staining of lung tissue sections and dissociated lung cells. To better define the temporal relationship between KGF administration and susceptibility to IAV infection in vivo, we administered KGF 120, 48, 24, and 0 h before intrapulmonary IAV challenge and assessed the percentages of proliferating and IAV-infected, alveolar type II (AECII) cells in dispersed lung cell populations. Peak AECII infectivity coincided with the timing of KGF administration that also induced peak AECII proliferation. AECII from mice that were given intrapulmonary KGF before isolation and then infected with IAV ex vivo exhibited the same temporal pattern of proliferation and infectious susceptibility. KGF-induced increases in mortality, AECII proliferation, and enhanced IAV susceptibility were all reversed by pretreatment of the animals with the mTOR inhibitor rapamycin before mitogenic stimulation. Taken together, these data suggest mTOR signaling-dependent, mitogenic conditioning of AECII is a determinant of host susceptibility to infection with IAV.

The Effects of PM2.5 from Asian Dust Storms on Emergency Room Visits for Cardiovascular and Respiratory Diseases

A case-crossover study examined how PM_2.5 from Asian Dust Storms (ADS) affects the number of emergency room (ER) admissions for cardiovascular diseases (CVDs) and respiratory diseases (RDs). Our data indicated that PM_2.5 concentration from ADS was highly correlated with ER visits for CVDs and RDs. The odds ratios (OR) increased by 2.92 (95% CI: 1.22–5.08) and 1.86 (95% CI: 1.30–2.91) per 10 µg/m³ increase in PM_2.5 levels, for CVDs and RDs, respectively. A 10 µg/m³ increase in PM_2.5 from ADSs was significantly associated with an increase in ER visits for CVDs among those 65 years of age and older (an increase of 2.77 in OR) and for females (an increase of 3.09 in OR). In contrast, PM_2.5 levels had a significant impact on RD ER visits among those under 65 years of age (OR = 1.77). The risk of ER visits for CVDs increased on the day when the ADS occurred in Taiwan and the day after (lag 0 and lag 1); the corresponding risk increase for RDs only increased on the fifth day after the ADS (lag 5). In Taiwan’s late winter and spring, the severity of ER visits for CVDs and RDs increases. Environmental protection agencies should employ an early warning system for ADS to reduce high-risk groups’ exposure to PM_2.5.

Fine Particulate Matter Concentrations in Urban Chinese Cities, 2005-2016: A Systematic Review

Background: Particulate matter pollution has become a growing health concern over the past few decades globally. The problem is especially evident in China, where particulate matter levels prior to 2013 are publically unavailable. We conducted a systematic review of scientific literature that reported fine particulate matter (PM_2.5) concentrations in different regions of China from 2005 to 2016. Methods: We searched for English articles in PubMed and Embase and for Chinese articles in the China National Knowledge Infrastructure (CNKI). We evaluated the studies overall and categorized the collected data into six geographical regions and three economic regions. Results: The mean (SD) PM_2.5 concentration, weighted by the number of sampling days, was 60.64 (33.27) μg/m³ for all geographic regions and 71.99 (30.20) μg/m³ for all economic regions. A one-way ANOVA shows statistically significant differences in PM_2.5 concentrations between the various geographic regions (F = 14.91, p < 0.0001) and the three economic regions (F = 4.55, p = 0.01). Conclusions: This review identifies quantifiable differences in fine particulate matter concentrations across regions of China. The highest levels of fine particulate matter were found in the northern and northwestern regions and especially Beijing. The high percentage of data points exceeding current federal regulation standards suggests that fine particulate matter pollution remains a huge problem for China. As pre-2013 emissions data remain largely unavailable, we hope that the data aggregated from this systematic review can be incorporated into current and future models for more accurate historical PM_2.5 estimates.

The impact of ambient fine particles on influenza transmission and the modification effects of temperature in China: A multi-city study

BACKGROUND

There is good evidence that air pollution is a risk factor for adverse respiratory and vascular health outcomes. However, data are limited as to whether ambient fine particles contribute to the transmission of influenza and if so, how the association is modified by weather conditions.

OBJECTIVES

We examined the relationship between ambient PM_2.5 and influenza incidence at the national level in China and explored the associations at different temperatures.

METHODS

Daily data on concentrations of particulate matter with aerodynamic diameter<2.5μm (PM_2.5) and influenza incidence counts were collected in 47 Chinese cities. A Poisson regression model was used to estimate the city-specific PM_2.5-influenza association, after controlling for potential confounders. Then, a random-effect meta-analysis was used to pool the effects at national level. In addition, stratified analyses were performed to examine modification effects of ambient temperature.

RESULTS

For single lag models, the highest effect of ambient PM_2.5 on influenza incidence appeared at lag day 2, with relative risk (RR) of 1.015 (95% confidence interval (CI): 1.004, 1.025) associated with a 10μg/m³ increase in PM_2.5. For moving average lag models, the significant association was found at lag 2-3days, with RR of 1.020 (95% CI: 1.006, 1.034). The RR of influenza transmission associated with PM_2.5 was higher for cold compared with hot days. Overall, 10.7% of incident influenza cases may result from exposure to ambient PM_2.5.

CONCLUSIONS

Ambient PM_2.5 may increase the risk of exposure to influenza in China especially on cooler days. Control measures to reduce PM_2.5 concentrations could potentially also be of benefit in lowering the risk of exposure and subsequent transmission of influenza in China.

Haze is a risk factor contributing to the rapid spread of respiratory syncytial virus in children

This study investigated whether respiratory syncytial virus (RSV) infection in children was associated with ambient temperature and air pollutants in Hangzhou, China. A distributed lag non-linear model (DLNM) was used to estimate the effects of daily meteorological data and air pollutants on the incidence of RSV infection among children. A total of 3650 childhood RSV infection cases were included in the study. The highest air pollutant concentrations were in January to May and October to December during the year. The yearly RSV-positive rate was 10.0 % among children with an average age of 4.3 months. The highest RSV-positive rate occurred among patients 0 to 3 months old. Children under 6.5 months old accounted for 80 % of the total patients infected by RSV. A negative correlation was found between ambient temperature and RSV infection, and it was strongest with minimum ambient temperature (r = -0.804, P < 0.001). There was a positive correlation between the infection rate and the particulate matter (PM) 2.5 (r = 0.446, P < 0.001), PM10 (r = 0.397, P < 0.001), SO₂ (r = 0.389, P < 0.001), NO₂ (r = 0.365, P < 0.001) and CO (r = 0.532, P < 0.001). The current study suggested that temperature was an important factor associated with RSV infection among children in Hangzhou. Air pollutants significantly increased the risk of RSV infection with dosage, lag and cumulative effects.

Network Analysis of Fine Particulate Matter (PM2.5) Emissions in China

Specification of PM_2.5 spatial and temporal characteristics is important for understanding PM_2.5 adverse effects and policymaking. We applied network analysis to studying the dataset MIX, which contains PM_2.5 emissions recorded from 2168 monitoring stations in China in 2008 and 2010. The results showed that for PM_2.5 emissions from industrial sector 8 clusters were found in 2008 but they merged together into a huge cluster in 2010, suggesting that industrial sector underwent an integrating process. For PM_2.5 emissions from electricity generation sector, strong locality of clusters was revealed, implying that each region had its own electricity generation system. For PM_2.5 emissions from residential sector, the same pattern of 10 clusters was uncovered in both years, implicating the household energy consumption unchanged from 2008 to 2010. For PM_2.5 emissions from transportation sector, the same pattern of 5 clusters with many connections in-between was unraveled, indicating the high-speed development of transportation nationalwidely. Except for the known elements, mercury (Hg) surfaced as an element for particle nucleation. To our knowledge, this is the first network study in this field.

Association of indoor air pollution from coal combustion with influenza-like illness in housewives

An association of influenza-like illness (ILI) with outdoor air pollution has been reported. However, the effect of indoor air pollution on ILI was rarely investigated. We aimed to determine an association of indoor air pollution from coal combustion (IAPCC) and lifestyle with ILI risk in housewives, and the modification effect of phase II metabolic enzyme genes. We recruited 403 housewives for a cross-sectional study in Shanxi Province, China, including 135 with ILI frequency (≥1 time per year in the past ten years) as the case group and 268 with ILI frequency (<1 times per year) as the control group. Information on their energy usage characteristics and lifestyle was collected by questionnaires, as well as the single nucleotide polymorphisms (SNPs) of epoxide hydrolase 1 (rs1051740 and rs2234922), N-acetyltransferase 2 (rs1041983), and glutathione S-transferase (rs1695). We used exposure index to indicate the level of IAPCC among housewives. Our results revealed that the exposure index was positively correlated with ILI frequency. A significant dose-response trend between the exposure index and ILI risk was found with or without adjusting for confounders. Cooking frequency in kitchen with coal as primary fuel and ventilation frequency in the living room or bedroom with a coal-fueled stove for heating during the heating season were two important risk factors to affect ILI frequency. Only rs1051740 was found to be associated with exposure index, whereas it didn't have interaction effect with exposure index on ILI frequency. In conclusion, IAPCC and SNPs of rs1051740 were both associated with ILI frequency.

The role of the PM2.5-associated metals in pathogenesis of child Mycoplasma Pneumoniae infections: a systematic review

The peak occurrence of Mycoplasma pneumoniae (M. pneumoniae) infections in childhood and haze episodes is concurrent. Together, the prevalence of macrolide-resistant M. pneumoniae varies among countries might also be related to the concentration of ambient fine particulate mass (aerodynamic diameter ≤2.5 μm, PM2.5). Numerous cohort studies have identified consistent associations between ambient PM2.5 and cardiorespiratory morbidity and mortality. PM2.5 is a carrier of the heavy metals. The relationship between PM2.5-associated metals and M. pneumoniae infections in childhood has been increasingly drawing public attention. First, we reviewed original articles and review papers in Pubmed and Web of Science regarding M. pneumoniae and PM2.5-associated metal and analyzed the structural basis of PM2.5-associated metal interaction with M. pneumoniae. Then, the possible mechanisms of action between them were conjectured. Mechanisms of oxidative stress induction and modulation of the host immune system and inflammatory responses via Toll-like receptors (TLRs) and/or the nuclear factor-kappa B (NF-κB) pathway are postulated to be the result of PM2.5-associated metal complex interaction with M. pneumoniae. In addition, a heavy metal effect on M. pneumoniae-expressed community-acquired respiratory distress syndrome (CARDS) toxin, and activation of the aryl hydrocarbon receptor (AhR) and TLRs to induce the differentiation of T helper (Th) cells are also regarded as important reasons for the influence of the heavy metals on the severity of M. pneumoniae pneumonia and the initial onset and exacerbation of M. pneumoniae associated asthma. PM2.5-associated metals via complex mechanisms can exert a great impact on the host through interaction with M. pneumoniae.

Effects of shisha smoking on carbon monoxide and PM2.5 concentrations in the indoor and outdoor microenvironment of shisha premises

There has been significant rise in shisha premises in the United Kingdom with an unsubstantiated belief that shisha smoking is harmless and relatively safe. This study aimed to assess the public health situation by evaluating the extent of shisha environmental tobacco smoke (ETS) exposure among those that work in, and are customers of shisha businesses. Concentrations of several ETS pollutants such as carbon monoxide (CO) and particulate matter with a diameter of less than 2.5μm (PM2.5) in shisha premises were measured using real-time sensors inside and outside twelve shisha premises and at 5 pubs/restaurants where smoking is prohibited. Mean concentration of CO (7.3±2.4mg/m(3)) and PM2.5 (287±233μg/m(3)) inside active shisha premises was higher than concentrations measured within the vicinity of the shisha premises (CO: 0.9±0.7mg/m(3) and PM2.5: 34±14μg/m(3)) and strongly correlated (PM2.5 R=0.957). Concentrations were higher than indoor concentrations in pubs and restaurants where smoking is not permitted under UK law. The number of shisha pipes was a strong predictor of the PM2.5 concentrations. The study also assessed the risk perception within patrons and managers, with only 25% being aware of the risks associated to shisha smoking. The study identifies owners, employees and consumers within active shisha premises being exposed to concentrations of CO and PM2.5 at levels considered hazardous to human health. The results and outcome of this research serve as a basis to influence a discussion around the need of developing specific policies to protect consumers and employees of such premises.

Impact of ambient fine particulate matter (PM2.5) exposure on the risk of influenza-like-illness: a time-series analysis in Beijing, China

BACKGROUND

Air pollution in Beijing, especially PM2.5, has received increasing attention in the past years. Although exposure to PM2.5 has been linked to many health issues, few studies have quantified the impact of PM2.5 on the risk of influenza-like illness (ILI). The aim of our study is to investigate the association between daily PM2.5 and ILI risk in Beijing, by means of a generalized additive model.

METHODS

Daily PM2.5, meteorological factors, and influenza-like illness (ILI) counts during January 1, 2008 to December 31, 2014 were retrieved. An inverse Gaussian generalized additive model with log link function was used to flexibly model the nonlinear relationship between the PM2.5 (single- and multiday lagged exposure) and ILI risk, adjusted for the weather conditions, seasonal and year trends. We also assessed if the effect of PM2.5 differs during flu season versus non-flu season by including the interaction term between PM2.5 and flu season in the model. Furthermore, a stratified analysis by age groups was conducted to investigate how the effect of PM2.5 differs across age groups.

RESULTS

Our findings suggested a strong positive relationships between PM2.5 and ILI risk at the flu season (October-April) (p-value < 0.001), after adjusting for the effects of ambient daily temperature and humidity, month and year; whereas no significant association was identified at the non-flu season (May-September) (p-value = 0.174). A short term delayed effect of PM2.5 was also identified with 2-day moving average (current day to the previous day) of PM2.5 yielding the best predictive power. Furthermore, PM2.5 was strongly associated with ILI risk across all age groups (p-value < 0.001) at the flu season, but the effect was the most pronounced among adults (age 25-59), followed by young adults (age 15-24), school children (age 5-14) and the elderly (age 60+) and the effect of PM2.5 was the least pronounced for children under 5 years of age (age < 5).

CONCLUSIONS

Ambient PM2.5 concentrations were significantly associated with ILI risk in Beijing at the flu season and the effect of PM2.5 differed across age groups, in Beijing, China.

Fine Particulate Matter Pollution and Hospital Admissions for Respiratory Diseases in Beijing, China

Fine particulate matter has become the premier air pollutant of Beijing in recent years, enormously impacting the environmental quality of the city and the health of the residents. Fine particles with aerodynamic diameters of 0~0.3 μm, 0.3~0.5 μm, and 0.5~1.0 μm, from the yeasr 2007 to 2012, were monitored, and the hospital data about respiratory diseases during the same period was gathered and calculated. Then the correlation between respiratory health and fine particles was studied by spatial analysis and grey correlation analysis. The results showed that the aerial fine particulate matter pollution was mainly distributed in the Zizhuyuan sub-district office. There was a certain association between respiratory health and fine particles. Outpatients with respiratory system disease in this study area were mostly located in the southeastern regions (Balizhuang sub-district office, Ganjiakou sub-district office, Wanshoulu sub-district office, and Yongdinglu sub-district office) and east-central regions (Zizhuyuan sub-district office and Shuangyushu sub-district office) of the study area. Correspondingly, PM₁ (particulate matter with aerodynamic diameter smaller than 1.0 um) concentrations in these regions were higher than those in any other regions. Grey correlation analysis results showed that the correlation degree of the fine particle concentration with the number of outpatients is high, and the smaller fine particles had more obvious effects on respiratory system disease than larger particles.