Charlene W. Bayer

OUTDOOR AIR POLLUTION: Asthma and Other Concerns

Despite governmental efforts to improve the quality of outdoor air, a significant number of children growing up in the US are exposed to airborne pollutants. It is now recognized that infants generally at risk for atrophy when exposed to specific environmental airborne pollutants are more likely to develop asthma. Once asthma is established, airborne pollutants are important triggers in causing exacerbations. Airborne ozone and suspended articles are the two most important criteria pollutants with respect to exposure prevalence and suspected adverse health effects in US children. Pediatricians should be involved both in community advocacy programs to improve air quality and as knowledgeable practitioners in discussing practical air pollution avoidance strategies with patients and their families.

Potential and Challenges for Mid-Infrared Sensors in Breath Diagnostics

Exhaled breath contains more than 1000 constituents at trace level concentrations, with a wide variety of these compounds potentially serving as biomarkers for specific diseases, physiologic status, or therapeutic progress. Some of the compounds in exhaled breath (EB) are well studied, and their relationship with disease pathologies is well established. However, molecularly specific analysis of such biomarkers in EB at clinically relevant levels remains an analytical and practical challenge due to the low levels of such biomarkers frequently below the ppb (v/v) range in EB. In this contribution, mid-infrared (MIR) spectroscopic sensing techniques are reviewed for potential application in breath diagnostics. While the spectral regime from 3-20 ¿m has already been utilized for fundamental studies on breath analysis, significant further improvements are in demand for substantiating MIR spectroscopy and sensing techniques as a suitable candidate for clinically deployable breath analyzers. Several advantageous features including inherent molecular selectivity, real-time monitoring capability, comparable ease of operation, potentially low costs, and a compact device footprint promise reliable optical diagnostics in the MIR. Hence, while the application of MIR spectroscopy and sensing systems to breath analysis yet appear in their infancy, recent progress on advanced MIR light sources, waveguides, and device concepts forecasts next-generation optical sensing platforms suitable for addressing the challenges of in situ breath diagnostics.

Traffic-related Occupational Exposures to PM2.5, CO, and VOCs in Trujillo, Peru

Abstract A traffic-related exposure study was conducted among 58 workers (drivers, vendors, traffic police, and gas station attendants) and 10 office workers as controls in Trujillo, Peru, in July 2002. PM2.5 was collected, carbon monoxide (CO) was measured, volatile organic compounds (VOCs) were sampled and analyzed. Newspaper vendors had the highest full-shift CO exposures (mean ± SD: 11.4 ± 8.9 ppm), while office workers had the lowest (2.0 ± 1.7 ppm). Bus drivers had the highest full-shift PM2.5 exposures (161±8.9 pg/m3), while gas station attendants (64 ± 26.5 pg/m3) and office workers (65 ± 8.5 μg/m3) were the lowest. Full-shift benzene/toluene/ethylbenzene/xylene exposures (BTEX) among gas station attendants (111/254/43/214 μg/m3) were much higher than those among van and taxi drivers. Several of the traffic-related occupational exposures studied were elevated and are of occupational health concern.

Exposure of Pregnant Women to Cookstove-Related Household Air Pollution in Urban and Periurban Trujillo, Peru

Although evidence suggests associations between maternal exposure to air pollution and adverse birth outcomes, pregnant womens exposure to household air pollution in developing countries is understudied. Personal exposures of pregnant women (N = 100) in Trujillo, Peru, to air pollutants and their indoor concentrations were measured. The effects of stove-use-related characteristics and ambient air pollution on exposure were determined using mixed-effects models. Significant differences in 48-hour kitchen concentrations of particulate matter (PM2.5), carbon monoxide (CO), and nitrogen dioxide (NO2) concentrations were observed across fuel types (p < 0.05). Geometric mean PM2.5 concentrations where 112 μg/m3 (confidence limits [CLs]: 52, 242 μg/m3) and 42 μg/m3 (21, 82 μg/m3) in homes where wood and gas were used, respectively. PM2.5 exposure was at levels that recent exposure-response analyses suggest may not result in substantial reduction in health risks even in homes where cleaner burning gas stoves were used.

The indoor environmental microbiome

The common belief and practice for controlling disease and allergic reactions has been to minimize human exposures to microbials in the indoor environment. However, with increasing knowledge and new technology, we are learning that this may not be the correct practice in all cases. The built environment is a complex ecosystem filled with a variety of dynamically interactive microbes. There are more than 10 bacterial cells per m in both indoor and outdoor air. Many of these microbes are essential and beneficial to our well-being rather than being pollutants or pathogens causing adverse impacts. The human body also is a complex system and a host for the human microbiome with 100 trillion bacteria in the gut alone. We are composed of 10 times as many microbial cells as human cells. Interfering with the human microbiome can have adverse impacts such as obesity, diabetes, asthma, and other chronic diseases as well as the more commonly attributed diseases such as diarrhea and acute infections. We are learning that similar conditions and dynamics are true of the indoor environmental microbiome. An attitude change is being developed about how we can design, operate, and maintain the indoor environment to maximize the beneficial microorganisms. We need to learn how the microorganisms interact with our environment and each other and with humans. Instead of assuming that all microorganisms indoors have a negative implication for human health, we need to learn what are the positive and negative health implications and how we design, construct, and control the indoor environment to maximize a naturally occurring microbiome supportive of human health and structure sustainability. There has been a surge of research into microorganism–host interactions. The human microbiome, such as through the US National Institute of Health’s (NIH) Human Microbiome Project (http://hmpdacc.org) is being characterized and the human health impacts assessed. Interdisciplinary research is ongoing to examine the indoor microbial community microbiome and its potential impact on human occupants. Until recently it was difficult to study airborne indoor microbial samples due to their ultra-low microbial biomass. However, improved DNA assay technology is allowing the analysis of the ultra-trace levels of microbial biomass. Now, architects, engineers, and biologists are working together to advance the science understanding the built environmental ecosystem. Research is showing that human occupants significantly influence the indoor environmental microbiology. Indoor environmental microbes are commonly associated with human skin and saliva since people constantly shed and acquire microbes. Increased human occupancy increases the indoor airborne bacterial load. The presence of pets has an impact on the indoor microbial community. A previous assumption was that pets adversely impacted the indoor microbial ecosystem; however, it has been shown that dogs have a positive impact on the human microbiome in buildings by creating a more broadly diverse bacterial community. We also are learning how building design and operational practices can change the microbial indoor environment. Ventilation unintentionally shapes the indoor microbial ecosystem. ‘Ventilation is the solution to pollution’ has long been the primary strategy to control indoor contaminants, including bioaerosols. However different ventilation strategies result in significantly different indoor microbial communities. Mechanical versus natural ventilation strategies may change the indoor taxa from primarily human oriented to primarily outdoor environment oriented or may have other influences. Mechanically ventilated spaces have less diverse microbial communities than naturally ventilated spaces and contain more human generated microbes, such as from skin and saliva. In a wellventilated space, the airborne community indoors will