Association of polycyclic aromatic hydrocarbons of the outdoor air in Ahvaz,southwest Iran during warm-cold season

Polycyclic aromatic hydrocarbons (PAHs) are one of the main components of urban air pollution. The level of concentration PAHs and effects are depended on seasonal variations and amount of exposure to PAHs. Nowadays, PAHs are one of the important pollutants that threat the public health. The purpose of this study was to evaluate the polycyclic aromatic hydrocarbons of the outdoor air in Ahvaz, southwest Iran using active sampling system during the warm and cold seasons of 2016. Data collection was performed daily during the study period in three stations in Ahvaz citizens at industrial, high traffic and residential areas. Omni sampler and equipped with PTFE filters (8*10) were utilized for sampling in this study. Gas chromatography with mass spectrometry (GC/MS) were utilized for detection of PAHs concentration (ngm^?3). Statistical SPSS software (SPSS version 16) was used to determine the effects of PAHs during warm and cold season. According to result this study, the industrial and residential areas had the highest and the lowest PAHs concentrations. Based on result this study, PAHs concentrations in three main areas at industrial, high traffic and residential were 7.021?±?3.45, 5.162?±?2.63 and 4.187?±?1.76 ngm^?3, respectively. The results showed that the average concentration of polycyclic aromatic hydrocarbons in three main areas outdoor air in Ahvaz were more than recommended scales by international organizations. According to this study, the mean of PAHs concentration in different areas was significantly higher than standard. Results showed that the short-term exposure to PAHs during cold season were higher than the levels of exposure during warm season. The levels of exposure to PAHs can increased risk of health endpoint and the oxidative stress.     

Study of ground-level ozone and its health risk assessment in residents in Ahvaz City,Iran during 2013

Ozone is a highly oxidative compound and is one of the important pollutants present in the atmosphere and at ground level. Concentration of ground-level ozone (GLO) pollutant depends on different factors such as the amount of VOC and NO_X, heat and location in the atmosphere. Ozone can cause health effects such as problems to breathe deeply and vigorously, inflame and damage the airways, bronchitis, reduced lung function in children and adults, emphysema and increase the frequency of asthma attacks. In this work, we focused on the determination of number of hospital admissions associated with ozone in Ahvaz with population of 1?000?000, during 2013. In this study, ozone data collections were through Iranian Environmental Protection Agency (Iranian EPA) and Meteorological Organization. Ozone data and meteorological parameters were used in Excel software to prepare input file of AirQ model. After running model, outputs presented in term of hospital admissions of ozone exposure were calculated. According to this study, “Havashenasi” and “Naderi” had the lowest and the highest ozone concentrations. Results of this study showed that if ozone concentrations were more than 20?μg/m³, approximately 12% hospital admissions were attributed by this pollutant. The results showed that the concentration of ozone was related to Ahvaz with an annual average of 223?μg/m³. Ozone concentration in Ahvaz was higher than standard. Mitigation measures in industries and transportation system in Ahvaz metropolitan is recommending to reduce the level of ozone in the ambient air. Changing the fuel process and using upgraded vehicles could be possibly very effective to diminish the impact of this pollutants on citizens.     

Study of heavy metal levels in indoor dust and their health risk assessment in children of Ahvaz city,Iran

The concentration of heavy metals in household dust and their health risks on children living in different areas of Ahvaz city was investigated during November 2013 to October 2014 in Iran. Totally, 108 dust samples were taken from their houses in three different areas including S₁ (industrial), S₂ (heavy traffic) and S₃ (residential zone far away from industrial and traffic emission sources). The samples were analyzed for eight selected heavy metals (Cr, Ni, Cu, Mn, Pb, Zn, Co and Cd) using an inductively coupled plasma optical emission spectroscopy (ICP-OES, Spectro Arcos Model, Germany). Exposure and risk assessment of these metals were estimated using USEPA’s exposure parameters. Results showed that the mean values of all heavy metals in tempered months were significantly higher than the other months (p?<?0.05). Cancer risk and non-carcinogenic risk (hazard index) of Ni, Cr, Cd and Pb from indoor dust exposure were estimated for children via three exposure pathways (ingestion, inhalation and dermal contact). The non-cancer risks to children in all samples were lower than acceptable level of 1, while the potential cancer risks from Ni intake in S₁ and S₂ were 1.57E???06 and 1.19E???06, respectively, and for Cr in S₁ and S₂, it was 1.43E???06 and 1.15E???06, respectively, which these values were slightly higher than the acceptable level (1?×?10^?6). In conclusion, household dust of Ahvaz city would probably have a significant potential to cause cancer in most exposed children.     

Association of anesthetic toxic isoflurane gases of the indoor air of operating room,Ahvaz, Iran during 2016

Operating rooms (ORs) in hospital wards are very important because of special conditions of patients. The hazards of contact with low concentrations of anesthetic gases (AG) are undeniable. Nowadays AG isoflurane is one of the important pollutants which is in the air of ORs and used in anesthesia. The purpose of this study was to evaluate the level of anesthetic toxic isoflurane gases of the indoor air of Razi, Golestan and Emam educational hospitals ORs, using active sampling system during 2016. In this study, in order to sampling and detection of isoflurane concentration (ppm), a portable pump (SKC pump) and tubes (Sorbent Tube Tenax TA 250?mg) were utilized. The sampling was done in three different points of the ORs. According to this study, the “Razi” and “Emam” hospitals had the highest and the lowest isoflurane concentrations. According to the results of this study, isoflurane concentrations in three main educational hospital ORs affiliated to the Ahvaz Jundishapur University of medical sciences were 2.342, 2.15 and 2.04?ppm, respectively. According to this study, the average concentration of isoflurane in three main educational hospitals was more than recommended scales by international organizations (2?ppm) and it sounds that exposure to this amount of gas would be the cause of health disorders for staff. The results showed that the mean of isoflurane concentration in different parts of ORs with standard ventilation system was significantly lower than those ORs in which they did not have standard ventilation. While environmental health management and AG contamination in ORs have been ignored, they can cause disorders in ORs’ staffs and causing more spiritual and material costs.     

Traffic, air pollution, and health

This paper discusses emerging information on exposure to air pollution from traffic and health and raises two key questions with regard to the impact of traffic on public health: 1) is there sufficient evidence to infer that traffic is causing adverse health effects, and; 2) what is the magnitude of the adverse impact of traffic on health? Topics addressed include characterization of exposure to traffic-related pollutants; the findings of epidemiological studies to date; and investigative approaches and the related challenges - including bias, model-based conclusions, and sample size issues--in characterizing the health effects of air pollution from traffic. Also considered are the known health effects of two of the major pollutants produced by vehicle exhaust--particles and ozone. The evidence points to traffic as a threat to public health that will be managed with great difficulty; however, more research is needed to refine our understanding of the health consequences of traffic exposures and as a basis for formulating mitigation policies. This paper discusses emerging information on exposure to air pollution from traffic and health and raises two key questions with regard to the impact of traffic on public health: 1) is there sufficient evidence to infer that traffic is causing adverse health effects, and; 2) what is the magnitude of the adverse impact of traffic on health? Topics addressed include characterization of exposure to traffic-related pollutants; the findings of epidemiological studies to date; and investigative approaches and the related challenges - including bias, model-based conclusions, and sample size issues - in characterizing the health effects of air pollution from traffic. Also considered are the known health effects of two of the major pollutants produced by vehicle exhaust - particles and ozone. The evidence points to traffic as a threat to public health that will be managed with great difficulty; however, more research is needed to refine our understanding of the health consequences of traffic exposures and as a basis for formulating mitigation policies.     

Concentration of air pollutants as toxic matter in urban and rural areas of Ahvaz

The aim of this study is to survey the concentrations of air pollutants in rural and urban areas in Ahvaz city during two seasons. We used ANOVA to determine the differences between the areas. Paired t-test was used to compare the concentrations of the air pollutants in cold season and hot season. The concentration of the air pollutants in cold season was higher than warm season except for O₃. Mobile vehicles represent the major source of air pollution in many areas, and the concentrations of traffic pollutants are greater near urban areas. The trend of changes in PM concentration in cold and warm seasons depends on dust storms occurrence.     

Neurotoxicity following acute inhalation of aerosols generated during resistance spot weld-bonding of carbon steel

Abstract

Welding generates complex metal aerosols, inhalation of which is linked to adverse health effects among welders. An important health concern of welding fume (WF) exposure is neurological dysfunction akin to Parkinson's disease (PD). Some applications in manufacturing industry employ a variant welding technology known as “weld-bonding” that utilizes resistance spot welding, in combination with adhesives, for metal-to-metal welding. The presence of adhesives raises additional concerns about worker exposure to potentially toxic components like Methyl Methacrylate, Bisphenol A and volatile organic compounds (VOCs). Here, we investigated the potential neurotoxicological effects of exposure to welding aerosols generated during weld-bonding. Male Sprague–Dawley rats were exposed (25?mg/m³ targeted concentration; 4?h/day?×?13 days) by whole-body inhalation to filtered air or aerosols generated by either weld-bonding with sparking (high metal, low VOCs; HM) or without sparking (low metal; high VOCs; LM). Fumes generated under these conditions exhibited complex aerosols that contained both metal oxide particulates and VOCs. LM aerosols contained a greater fraction of VOCs than HM, which comprised largely metal particulates of ultrafine morphology. Short-term exposure to LM aerosols caused distinct changes in the levels of the neurotransmitters, dopamine (DA) and serotonin (5-HT), in various brain areas examined. LM aerosols also specifically decreased the mRNA expression of the olfactory marker protein (Omp) and tyrosine hydroxylase (Th) in the olfactory bulb. Consistent with the decrease in Th, LM also reduced the expression of dopamine transporter (Slc6a3; Dat), as well as, dopamine D2 receptor (Drd2) in the olfactory bulb. In contrast, HM aerosols induced the expression of Th and dopamine D5 receptor (Drd5) mRNAs, elicited neuroinflammation and blood–brain barrier-related changes in the olfactory bulb, but did not alter the expression of Omp. Our findings divulge the differential effects of LM and HM aerosols in the brain and suggest that exposure to weld-bonding aerosols can potentially elicit neurotoxicity following a short-term exposure. However, further investigations are warranted to determine if the aerosols generated by weld-bonding can contribute to persistent long-term neurological deficits and/or neurodegeneration.     

Strategies for integral metabolism profile of multiple compounds in herbal medicines: pharmacokinetics, metabolites characterization and metabolic interactions

Herbal medicines (HMs) are gaining more and more attention all over the world, because of their significant curative effect in treating multi-factorial diseases. Recently, the in vivo and in vitro metabolism study of HMs has become an important issue because these data can help us to better understand the efficacies and toxicities of HMs. However, the integral metabolism profile of HMs is confronted with many challenges: 1) HM is a multi-component system; 2) most components are unknown (nontarget); 3) trace of components in HM. Given the challenges described above, the demand for more powerful bioanalytical tools and strategies that are adequate for integral metabolism profile of HMs' multi-components has increased. In the past few years, newer methods, or adaptations to methods, have been published, and this review will attempt to discuss new improvements in strategies and methodologies for HMs' multi-component ADME evaluation. In particular, improvements have been reported for experimental approaches to pharmacokinetics study of HMs, as well as strategies applied to metabolites characterization of HMs' multi-components, and the metabolic interactions between ingredients in HMs, including advance and proposed strategy: "chemical fishing" based strategy for metabolic interactions of HMs.     

Ecological and health risk assessment of heavy metals in the Hattar industrial estate,Pakistan

Abstract

This study aimed to determine the heavy metals (HMs) contaminations in soil of the Hattar industrial estate (HIE), Haripur, Khyber Pakhtunkhwa. For this purpose, various types of soils were collected in HIE and analyzed for the HMs concentrations. The HMs showed highest contamination levels in wastewater irrigated agriculture soil (WWIAS), followed by waste dump site soil (WDSS), and the lowest in range land soil (RLS). Determined HMs concentrations were used for pollution quantification factors, including contamination factors (CFs), pollution load index (PLI), ecological risk factor (ER), and potential health risk assessment, including chronic or non-cancer and cancer risk levels.     

Herbal medicines: challenges in the modern world. Part 1. Australia and New Zealand

As in many developed countries, herbal medicines (HMs) are widely used in Australia and New Zealand (NZ). The popularity of HM continues to rise. Western, Asian and indigenous HMs are used, reflecting the cultural diversity of people in this region. HMs in Australia are regulated on a risk-based system with many HMs identified as being low risk. The legislation was reviewed in 2015 and proposals for change are under consideration. In NZ, it is recognised that current regulations for HMs and other natural health products (NHPs) do not adequately protect public health. NZ is entering a phase of regulatory change for this sector, and proposals for a ‘light-touch’ regulatory framework for NHPs are planned to be introduced into legislation during 2016.     

A review of controlled human SO₂ exposure studies contributing to the US EPA integrated science assessment for sulfur oxides

Laboratory studies involving intentional and highly controlled exposures to air pollutants among groups of human volunteers provide valuable information related to the potential health effects of pollutants regulated under the US Clean Air Act. These controlled human exposure studies often provide biological plausibility for the associations between air-pollutant concentration and a given health endpoint observed in epidemiologic investigations. In some cases, results from human laboratory studies provide evidence of a relevant health effect at ambient or near-ambient concentrations and thus directly support the selection of air quality standard levels. In the recently completed review of the US National Ambient Air Quality Standards (NAAQS) for sulfur dioxide (SO?), the US Environmental Protection Agency (EPA) concluded that short-term exposures to SO? are causally associated with an increase in respiratory morbidity. This determination was based in large part on findings from laboratory studies of controlled exposures to SO? among small groups of asthmatic individuals. The purpose of this review is to concisely present an overview of the evidence from controlled human exposure studies of SO?-induced respiratory health effects following short-term exposures. While the majority of these studies were conducted over 20 years ago, the findings and insights gained from this work continues to play an integral role in evaluating the respiratory effects of ambient exposures to SO?.     

An effort to test the embryotoxicity of benzene,toluene, xylene,and formaldehyde to murine embryonic stem cells using airborne exposure technique

Benzene, toluene, xylene, and formaldehyde are well-known indoor air pollutants, especially after house decoration. They are also common pollutants in the working places of the plastic industry, chemical industry, and leather industry. It has been reported that these pollutants cause people to be irritated, sick, experience a headache, and be dizzy. They also have the potential to induce asthma, aplastic anemia, and leukemia, even cause abortion or fetus malformation in humans. In this study, the airborne toxicity of benzene, toluene, xylene, and formaldehyde to murine embryonic stem cells (mES cells) were tested using airborne exposure technique to evaluate the mES cell airborne exposure model on embryotoxicity prediction. Briefly, mES cells were cultured on Transwell inserts and were exposed to an airborne surrounding of test chemicals in a chamber for 1?h at 37°C. Cytotoxicity was determined using the MTT assay after further culture for 18?h at 37°C in normal medium. The airborne IC₅₀ (50% inhibition concentration) of benzene, toluene, xylene, and formaldehyde derived from the fitted dose-response curves were 17,400?±?1290, 16,000?±?250, 4680?±?500, and 620?±?310 ppm, respectively. Formaldehyde was found to be the compound most toxic to mES cells compared to benzene homologues. The toxicity data had good correlation with the in vivo data. The results showed that the mES airborne exposure model may be used to predict embryotoxicity of volatile organic compounds.     

Associations of polycyclic organic matter in outdoor air with decreased birth weight: a pilot cross-sectional analysis.

The association between births that are small for gestational age and outdoor airborne polycyclic organic matter (POM) was examined in New Jersey, a highly urban state. This pilot study utilizes a cross-sectional investigation combining maternal and pregnancy outcome information from birth certificates with air toxics data from the U.S. Environmental Protection Agency Cumulative Exposure Project and census data at the census tract level. The exposure categories were based on tertiles of modeled average POM concentrations for each census tract in New Jersey. High POM exposure was positively associated with delivery of "small for gestational age" (SGA) births. After adjustment for potential individual-level confounding factors, the odds ratios for term, preterm, and all SGA were 1.22 (1.16-1.27), 1.26 (1.07-1.49), and 1.22 (1.17-1.27), respectively, for the highest exposure tertile in the urban population of the state (89% of the state's birth population). For group-level variables, the corresponding ORs were 1.12 (1.07-1.18), 1.23 (1.02-1.47), and 1.13 (1.07-1.18). The results of this study suggest that residential exposure to airborne polycyclic organic matter (POM) is associated with increased prevalence of "small for gestational age" births among urban population. Cross-sectional investigations combining air dispersion models with routinely collected population-based health and census data could be a useful approach for identifying the hazardous air pollutants of greatest public health concern.     

Air pollution and respiratory viral infection

Despite current regulations, which limit the levels of certain air pollutants, there are still a number of adverse health effects that result from exposure to these agents. Numerous epidemiological studies have noted an association between the levels of air pollution and hospital admissions for a variety of different health reasons, including a number of respiratory diseases, as well as increased morbidity and mortality associated with various respiratory conditions and diseases. Because of the large impact respiratory virus infections have on morbidity and even mortality, it is important to understand whether and how exposure to common air pollutants could exacerbate the susceptibility to and severity of respiratory virus infections. This review focuses on current epidemiological and experimental studies, which have examined the association between and effect of air pollutants and respiratory viral infections, as well as potential mechanisms associated with these effects. Examined in this review are U.S. Environmental Protection Agency (EPA) "criteria" pollutants nitrogen dioxide (NO(2)), ozone (O(3)), and particulate matter (PM), as well as indoor pollutants such as environmental tobacco smoke (ETS) and combustion products of biomass fuels. Although a number of studies indicate associations between exposure to air pollutants and increased risk for respiratory virus infections, potential mechanisms mediating these effects are largely unexplored. Therefore, additional studies, both epidemiologic and mechanistic, are necessary to increase our understanding of how exposure to air pollutants could affect respiratory virus infections, especially in populations already at risk of developing significant morbidity/mortality after infections with respiratory viruses.     

The complexities of air pollution regulation: the need for an integrated research and regulatory perspective.

The Clean Air Act mandates the U.S. Environmental Protection Agency to periodically reassess existing and new science that underlie the regulation of major ambient pollutants -- particulate matter (PM) and tropospheric ozone being most notable. While toxic effects have been ascribed individually to these and other pollutants in the air, it is clear that mixtures of these contaminants have the potential to interact and thereby influence their overall toxic outcomes. It follows that a more comprehensive assessment of the potential health effects of the air pollution complex might better protect human health; however, traditional regulatory drivers and funding constraints have impeded progress to such a goal. Despite difficulties in empirically conducting studies of complex mixtures of air pollutants and acquiring relevant exposure data, there remains a need to develop integrated, interdisciplinary research and analytical strategies to provide more comprehensive (and relevant) assessments of associated health outcomes and risks. The research and assessment communities are endeavoring to dissect this complexity using varied approaches Here we present five interdisciplinary perspectives of this evolving line of thought among researchers and those who use such data in assessment: (1) analyses that coordinate air quality-health analyses utilizing representative polluted U.S. air sheds to apportion source and component-specific health risks; (2) novel approaches to characterize air quality in terms of emission sources and how emission reduction strategies might effectively impact pollutant levels; (3) insights from present-day studies of effects of single ambient pollutants in animal and controlled clinical toxicology studies and how these are evolving to address air pollution; (4) refinements in epidemiologic health assessments that take advantage of the complexities of existent air quality conditions; and (5) new approaches to integrative analyses to establish the criteria for regulation of PM and other criteria pollutants. As these examples illustrate, implementing multidisciplined and integrative strategies offer the promise of more realistic and relevant science, greater reductions in uncertainty, and improved overall air pollution assessment. The regulatory mandate may lag behind the science, but real gains both in public health benefit and the science to dissect complex problems will result.     

Effect of diesel exhaust inhalation on blood markers of inflammation and neurotoxicity: a controlled,blinded crossover study

Context: Epidemiological studies and animal research have suggested that air pollution may negatively impact the central nervous system (CNS). Controlled human exposure studies of the effect of air pollution on the brain have potential to enhance our understanding of this relationship and to inform potential biological mechanisms.

Objectives: Biomarkers of systemic and CNS inflammation may address whether air pollution exposure induces inflammation, with potential for CNS negative effects.

Materials and methods: Twenty-seven healthy adults were exposed to two conditions: filtered air (FA) and diesel exhaust (DE) (300?μg PM_2.5/m³) for 120?min, in a double-blinded crossover study with exposures separated by four weeks. Prior to and at 0, 3, and 24?h following each exposure, serum and plasma were collected and analyzed for inflammatory cytokines interleukin 6 (IL-6) and tumour necrosis factor alpha (TNF-α), the astrocytic protein S100b, the neuronal cytoplasmic enzyme neuron-specific enolase (NSE), and serum brain-derived neurotrophic factor (BDNF). We hypothesized that IL-6, TNF-α, S100b and NSE would increase, and BDNF would decrease, following DE exposure.

Results: At no time-point following exposure to DE was a significant increase in concentration from baseline seen for IL-6, TNF-α, S100b, or NSE relative to FA exposure. Similarly, no significant decrease in BDNF concentration from baseline was seen following DE exposure, relative to FA. Furthermore, the repeated measures ANOVA considered for all time-points and biomarkers revealed no significant time-exposure interaction.

Discussion and conclusion: These results suggest that short-term exposure to DE amongst healthy adults does not acutely affect the systemic or CNS biomarkers that we measured.     

Synergistic effects of exposure to concentrated ambient fine pollution particles and nitrogen dioxide in humans

Context: Exposure to single pollutants e.g. particulate matter (PM) is associated with adverse health effects, but it does not represent a real world scenario that usually involves multiple pollutants.

Objectives: Determine if simultaneous exposure to PM and NO₂ results in synergistic interactions.

Materials and methods: Healthy young volunteers were exposed to clean air, nitrogen dioxide (NO₂, 0.5 ppm), concentrated fine particles from Chapel Hill air (PM_2.5CAPs, 89.5?±?10.7 µg/m³), or NO₂+PM_2.5CAPs for 2?h. Each subject performed intermittent exercise during the exposure. Parameters of heart rate variability (HRV), changes in repolarization, peripheral blood endpoints and lung function were measured before and 1 and 18?h after exposure. Bronchoalveolar lavage (BAL) was performed 18?h after exposure.

Results: NO₂ exposure alone increased cholesterol and HDL 18?h after exposure, decreased high frequency component of HRV one and 18?h after exposure, decreased QT variability index 1?h after exposure, and increased LDH in BAL fluid. The only significant change with PM_2.5CAPs was an increase in HDL 1?h after exposure, likely due to the low concentrations of PM_2.5CAPs in the exposure chamber. Exposure to both NO₂ and PM_2.5CAPs increased BAL α1-antitrypsin, mean t wave amplitude, the low frequency components of HRV and the LF/HF ratio. These changes were not observed following exposure to NO₂ or PM_2.5CAPs alone, suggesting possible interactions between the two pollutants.

Discussion and conclusions: NO₂ exposure may produce and enhance acute cardiovascular effects of PM_2.5CAPs. Assessment of health effects by ambient PM should consider its interactions with gaseous copollutants.     

Modeling long-term effects attributed to nitrogen dioxide (NO2) and sulfur dioxide (SO2) exposure on asthma morbidity in a nationwide cohort in Israel

Studies have provided extensive documentation that acutely elevated environmental exposures contribute to chronic health problems. However, only attention has been paid to the effects of modificate of exposure assessment methods in environmental health investigations, leading to uncertainty and gaps in our understanding of exposure– and dose–response relationships. The goal of the present study was to evaluate whether average or peak concentration exerts a greater influence on asthma outcome, and which of the exposure models may better explain various physiological responses generated by nitrogen dioxide (NO₂) or sulfur dioxide (SO₂) air pollutants. The effects of annual NO₂ and SO₂ exposures on asthma prevalence were determined in 137,040 17-year-old males in Israel, who underwent standard health examinations before induction to military service during 1999–2008. Three alternative models of cumulative exposure were used: arithmetic mean level (AM), average peak concentration (APC), and total number of air pollution exposure episodes (NEP). Air pollution data for NO₂ and SO₂ levels were linked to the residence of each subject and asthma prevalence was predicted using bivariate logistic regression. There was significant increased risk for asthma occurrence attributed to NO₂ exposure in all models with the highest correlations demonstrated using the APC model. Data suggested that exposure–response is better correlated with NO₂ peak concentration than with average exposure concentration in subjects with asthma. For SO₂, there was a weaker but still significant exposure response association in all models. These differences may be related to differences in physiological responses including effects on different regions of the airways following exposure to these pollutants. NO₂, which is poorly soluble in water, penetrates deep into the bronchial tree, producing asthmatic manifestations such as inflammation and increased mucus production as a result of high gaseous concentrations in the lung parenchyma. In contrast, SO₂, which is highly water soluble, exerts its effects rapidly in the upper airways, leading to similar limited correlations at all levels of exposure with fewer asthmatic manifestations observed. These data indicate that differing exposure assessment methods may be needed to capture specific disease consequences associated with these air pollutants.     

Herbal Medicines: challenges in the modern world. Part 5. status and current directions of complementary and alternative herbal medicine worldwide

Introduction: Herbal medicine (HM) use is growing worldwide. Single herb preparations, ethnic and modern HM formulations are widely used as adjunct therapies or to improve consumer wellbeing.

Areas covered: This final part in the publication series summarizes common tendencies in HM use as adjunct or alternative medicine, education of healthcare professionals and consumers, current and proposed guidelines regulating of production. We discuss potential HM-HM and HM-drug interactions that could lead to severe adverse events in situations where HMs are taken without proper medical professional oversight.

Expert commentary: A number of serious problems have arisen with the steady global increase in HM use. HM interaction with conventional drugs (CD) may result in inadequate dosing of CD or adverse reactions; HM-HM interaction within herbal supplements could lead to toxicity of formulations. Inadequate education of clinicians and patients regarding medicinal properties of HMs must be addressed regionally and globally to ensure consumer safety.