Estimating Lung Deposition of Fungal Spores Using Actual Airborne Spore Concentrations and Physiological Data.

Exposure to bioaerosols has been implicated in adverse respiratory symptoms, infectious diseases, and bioterrorism. Although these particles have been measured within residential and occupational settings in multiple studies, the deposition of bioaerosol particles within the human respiratory system has been only minimally explored. This paper uses real-world environmental measurement data of total fungal spores using Air-o-Cell cassettes in 16 different apartments and residents' physiological data in those apartments to predict respiratory deposition of the spores. The airborne spore concentrations were measured during the spring, summer, and fall. The respiratory deposition of five most prevalent spore genera-Ascospores, Aspergillus, Basidiospores, Cladosporium, and Myxomycetes-was predicted using three empirical models: the Multiple Path Particle Dosimetry model, using both the Yeh and age-specific versions, and the Bioaerosol Adaptation of the International Committee on Radiological Protection's Lung deposition model. The predicted total deposited number of spores was highest for Ascospores and Cladosporium. While the majority of spores deposit were in the extrathoracic region, there is a significant deposition for both Aspergillus and Cladosporium in the alveolar region, potentially leading to the development of aspergillosis or allergic asthma. Although the dose-response relationship is unknown, the estimate of the actual spore deposition could be the first step in determining such a relationship.

Comparison of real-time instruments and gravimetric method when measuring particulate matter in a residential building.

This study used several real-time and filter-based aerosol instruments to measure PM2.5 levels in a high-rise residential green building in the Northeastern US and compared performance of those instruments. PM2.5 24-hr average concentrations were determined using a Personal Modular Impactor (PMI) with 2.5 µm cut (SKC Inc., Eighty Four, PA) and a direct reading pDR-1500 (Thermo Scientific, Franklin, MA) as well as its filter. 1-hr average PM2.5 concentrations were measured in the same apartments with an Aerotrak Optical Particle Counter (OPC) (model 8220, TSI, Inc., Shoreview, MN) and a DustTrak DRX mass monitor (model 8534, TSI, Inc., Shoreview, MN). OPC and DRX measurements were compared with concurrent 1-hr mass concentration from the pDR-1500. The pDR-1500 direct reading showed approximately 40% higher particle mass concentration compared to its own filter (n = 41), and 25% higher PM2.5 mass concentration compared to the PMI2.5 filter. The pDR-1500 direct reading and PMI2.5 in non-smoking homes (self-reported) were not significantly different (n = 10, R2 = 0.937), while the difference between measurements for smoking homes was 44% (n = 31, R2 = 0.773). Both OPC and DRX data had substantial and significant systematic and proportional biases compared with pDR-1500 readings. However, these methods were highly correlated: R2 = 0.936 for OPC versus pDR-1500 reading and R2 = 0.863 for DRX versus pDR-1500 reading. The data suggest that accuracy of aerosol mass concentrations from direct-reading instruments in indoor environments depends on the instrument, and that correction factors can be used to reduce biases of these real-time monitors in residential green buildings with similar aerosol properties. IMPLICATIONS: This study used several real-time and filter-based aerosol instruments to measure PM2.5 levels in a high-rise residential green building in the northeastern United States and compared performance of those instruments. The data show that while the use of real-time monitors is convenient for measurement of airborne PM at short time scales, the accuracy of those monitors depends on a particular instrument. Bias correction factors identified in this paper could provide guidance for other studies using direct-reading instruments to measure PM concentrations.

Airborne Particulate Matter in Two Multi-Family Green Buildings: Concentrations and Effect of Ventilation and Occupant Behavior.

There are limited data on air quality parameters, including airborne particulate matter (PM) in residential green buildings, which are increasing in prevalence. Exposure to PM is associated with cardiovascular and pulmonary diseases, and since Americans spend almost 90% of their time indoors, residential exposures may substantially contribute to overall airborne PM exposure. Our objectives were to: (1) measure various PM fractions longitudinally in apartments in multi-family green buildings with natural (Building E) and mechanical (Building L) ventilation; (2) compare indoor and outdoor PM mass concentrations and their ratios (I/O) in these buildings, taking into account the effects of occupant behavior; and (3) evaluate the effect of green building designs and operations on indoor PM. We evaluated effects of ventilation, occupant behaviors, and overall building design on PM mass concentrations and I/O. Median PMTOTAL was higher in Building E (56 µg/m³) than in Building L (37 µg/m³); I/O was higher in Building E (1.3-2.0) than in Building L (0.5-0.8) for all particle size fractions. Our data show that the building design and occupant behaviors that either produce or dilute indoor PM (e.g., ventilation systems, combustion sources, and window operation) are important factors affecting residents' exposure to PM in residential green buildings.

Promoting routine stair use: evaluating the impact of a stair prompt across buildings.

BACKGROUND: Although studies have demonstrated that stair prompts are associated with increased physical activity, many were conducted in low-rise buildings over a period of weeks and did not differentiate between stair climbing and descent. PURPOSE: This study evaluated the impact of a prompt across different building types, and on stair climbing versus descent over several months. METHODS: In 2008-2009, stair and elevator trips were observed and analyzed at three buildings in New York City before and after the posting of a prompt stating "Burn Calories, Not Electricity" (total observations=18,462). Sites included a three-story health clinic (observations=4987); an eight-story academic building (observations=5151); and a ten-story affordable housing site (observations=8324). Stair and elevator trips up and down were recorded separately at the health clinic to isolate the impact on climbing and descent. Follow-up was conducted at the health clinic and affordable housing site to assess long-term impact. RESULTS: Increased stair use was seen at all sites immediately after posting of the prompt (range=9.2%-34.7% relative increase, p<0.001). Relative increases in stair climbing (20.2% increase, p<0.001) and descent (4.4% increase, p<0.05) were seen at the health clinic. At both sites with long-term follow-up, relative increases were maintained at 9 months after posting compared to baseline: 42.7% (p<0.001) increase in stair use at the affordable housing site and 20.3% (p<0.001) increase in stair climbing at the health clinic. CONCLUSIONS: Findings suggest that the prompt was effective in increasing physical activity in diverse settings, and increases were maintained at 9 months.

Mobile telephones, distracted attention, and pedestrian safety.

Driver distraction is a major cause of traffic accidents, with mobile telephones as a key source of distraction. In two studies, we examined distraction of pedestrians associated with mobile phone use. The first had 60 participants walk along a prescribed route, with half of them conversing on a mobile phone, and the other half holding the phone awaiting a potential call, which never came. Comparison of the performance of the groups in recalling objects planted along the route revealed that pedestrians conversing recalled fewer objects than did those not conversing. The second study had three observers record pedestrian behavior of mobile phone users, i-pod users, and pedestrians with neither one at three crosswalks. Mobile phone users crossed unsafely into oncoming traffic significantly more than did either of the other groups. For pedestrians as with drivers, cognitive distraction from mobile phone use reduces situation awareness, increases unsafe behavior, putting pedestrians at greater risk for accidents, and crime victimization.

Rail commuting duration and passenger stress.

Over 100 million Americans commute to work every weekday. Little is known, however, about how this aspect of work, which may indeed be the most stressful aspect of the job for some, affects human health and well-being. The authors studied a sample of 208 male and female suburban rail commuters who took the train to Manhattan, New York. The greater the duration of the commute, the larger the magnitude of salivary cortisol elevations in reference to resting baseline levels, the less the commuter's persistence on a task at the end of the commute, and the greater the levels of perceived stress. These effects were not moderated by gender. Commuting stress is an important and largely overlooked aspect of environmental health.