Faculty Bibliography

BACKGROUND: Hookahs are increasingly being used in the USA and elsewhere. Despite the popularity of hookah bars, there is a paucity of research assessing the health effects of hookah smoke, and although New York City (NYC) bans indoor tobacco smoking, hookah lounges claim that they only use herbal products without tobacco. This study investigated levels of multiple indices of indoor air pollution in hookah bars in NYC. METHODS: Air samples were collected in 8 hookah bars in NYC. Along with venue characteristics, real-time measurements of fine particulate matter (PM2.5), black carbon (BC), and carbon monoxide (CO), and total gravimetric PM, elemental carbon (EC), organic carbon (OC), and nicotine were collected in 1-2 hour sessions. RESULTS: Overall, levels of indoor air pollution increased with increasing numbers of active hookahs smoked. The mean (SD) real time PM2.5 level was 1179.9 (939.4) microg/m(3), whereas the filter-based total PM mean was 691.3 (592.6) microg/m(3). The mean real time BC level was 4.1 (2.3) microg/m(3), OC was 237.9 (112.3) microg/m(3), and CO was 32 (16) ppm. Airborne nicotine was present in all studied hookah bars (4.2 (1.5) microg/m(3)). CONCLUSIONS: These results demonstrate that despite the ban on smoking tobacco products, at the very least, some NYC hookah bars are serving tobacco-based hookahs, and have elevated concentrations of indoor air pollutants that may present a health threat to visitors and employees. Therefore, there is an urgent need for better air quality monitoring in such establishments and policies to combat this emerging public health threat.

BACKGROUND: Previous human exposure studies of traffic-related air pollutants have demonstrated adverse health effects in human populations by comparing areas of high and low traffic, but few studies have utilized microenvironmental monitoring of pollutants at multiple traffic locations while looking at a vast array of health endpoints in the same population. We evaluated inflammatory markers, heart rate variability (HRV), blood pressure, exhaled nitric oxide, and lung function in healthy participants after exposures to varying mixtures of traffic pollutants. METHODS: A repeated-measures, crossover study design was used in which 23 healthy, non-smoking adults had clinical cardiopulmonary and systemic inflammatory measurements taken prior to, immediately after, and 24 hours after intermittent walking for two hours in the summer months along three diverse roadways having unique emission characteristics. Measurements of PM2.5, PM10, black carbon (BC), elemental carbon (EC), and organic carbon (OC) were collected. Mixed effect models were used to assess changes in health effects associated with these specific pollutant classes. RESULTS: Minimal associations were observed with lung function measurements and the pollutants measured. Small decreases in BP measurements and rMSSD, and increases in IL-1beta and the low frequency to high frequency ratio measured in HRV, were observed with increasing concentrations of PM2.5 EC. CONCLUSIONS: Small, acute changes in cardiovascular and inflammation-related effects of microenvironmental exposures to traffic-related air pollution were observed in a group of healthy young adults. The associations were most profound with the diesel-source EC.

Human exposure studies, compared with cell and animal models, are heavily relied upon to study the associations between health effects in humans and air pollutant inhalation. Human studies vary in exposure methodology, with some work conducted in controlled settings, whereas other studies are conducted in ambient environments. Human studies can also vary in the health metrics explored, as there exists a myriad of health effect end points commonly measured. In this review, we compiled mini reviews of the most commonly used noninvasive health effect end points that are suitable for panel studies of air pollution, broken into cardiovascular end points, respiratory end points, and biomarkers of effect from biological specimens. Pertinent information regarding each health end point and the suggested methods for mobile collection in the field are assessed. In addition, the clinical implications for each health end point are summarized, along with the factors identified that can modify each measurement. Finally, the important research findings regarding each health end point and air pollutant exposures were reviewed. It appeared that most of the adverse health effects end points explored were found to positively correlate with pollutant levels, although differences in study design, pollutants measured, and study population were found to influence the magnitude of these effects. Thus, this review is intended to act as a guide for researchers interested in conducting human exposure studies of air pollutants while in the field, although there can be a wider application for using these end points in many epidemiological study designs.

The growing use of silver nanoparticles (AgNPs) in consumer products raises concerns about potential health effects. This study investigated the persistence and clearance of 2 different size AgNPs (20 and 110 nm) delivered to rats by single nose-only aerosol exposures (6 h) of 7.2 and 5.4 mg/m(3), respectively. Rat lung tissue was assessed for silver accumulations using inductively-coupled plasma mass spectrometry (ICP-MS), autometallography, and enhanced dark field microscopy. Involvement of tissue macrophages was assessed by scoring of silver staining in bronchoalveolar lavage fluid (BALF). Silver was abundant in most macrophages at 1 day post-exposure. The group exposed to 20 nm AgNP had the greatest number of silver positive BALF macrophages at 56 days post-exposure. While there was a significant decrease in the amount of silver in lung tissue at 56 days post-exposure compared with 1 day following exposure, at least 33% of the initial delivered dose was still present for both AgNPs. Regardless of particle size, silver was predominantly localized within the terminal bronchial/alveolar duct junction region of the lung associated with extracellular matrix and within epithelial cells. Inhalation of both 20 and 110 nm AgNPs resulted in a persistence of silver in the lung at 56 days post-exposure and local deposition as well as accumulation of silver at the terminal bronchiole alveolar duct junction. Further the smaller particles, 20 nm AgNP, produced a greater silver burden in BALF macrophages as well as greater persistence of silver positive macrophages at later timepoints (21 and 56 days).

Particulate matter (PM) varies in chemical composition and mass concentration based on location, source, and particle size. This study sought to evaluate the in vitro and in vivo toxicity of coarse (PM10-2.5) and fine (PM25) PM samples collected at 5 diverse sites within California. Coarse and fine PM samples were collected simultaneously at 2 rural and 3 urban sites within California during the summer. A human pulmonary microvascular endothelial cell line (HPMEC-ST1.6R) was exposed to PM suspensions (50 mug/mL) and analyzed for reactive oxygen species (ROS) after 5 hours of treatment. In addition, FVB/N mice were exposed by oropharyngeal aspiration to 50 mug PM, and lavage fluid was collected 24 hrs post-exposure and analyzed for total protein and %PMNs. Correlations between trace metal concentrations, endotoxin, and biological endpoints were calculated, and the effect of particle size range, locale (urban vs. rural), and location was determined. Absolute principal factor analysis was used to identify pollution sources of PM from elemental tracers of those sources. Ambient PM elicited an ROS and pro-inflammatory-related response in the cell and mouse models, respectively. These responses were dependent on particle size, locale, and location. Trace elements associated with soil and traffic markers were most strongly linked to the adverse effects in vitro and in vivo. Particle size, location, source, and composition of PM collected at 5 locations in California affected the ROS response in human pulmonary endothelial cells and the inflammatory response in mice.

The New York City (NYC) subway is the main mode of transport for over 5 million passengers on an average weekday. Therefore, airborne pollutants in the subway stations could have a significant impact on commuters and subway workers. This study looked at black carbon (BC) and particulate matter concentrations (PM2.5) in selected subway stations in Manhattan. BC and PM2.5 levels were measured in real time using a Micro-Aethalometer and a PDR-1500 Data RAM, respectively. Simultaneous samples were also collected on quartz filters for Organic and Elemental carbon (OC/EC) analysis and on Teflon filters for gravimetric and trace element analysis. In the underground subway stations, mean real time BC concentrations ranged from 5 to 23 microg/m3, with 1 minute average peaks >100 microg/m3, while real time PM2.5 levels ranged from 35 to 200 microg/m3. Mean EC levels ranged from 9 to 12.5 microg/m3. At street level on the same days, the mean BC and PM2.5 concentrations were below 3 microg/m3 and 10 microg/m3, respectively. This study shows that both BC soot and PM levels in NYC's subways are considerably higher than ambient urban street levels, and further monitoring and investigation of BC and PM subway exposures are warranted.