Indoor Sites Research Articles

Effects of Varying Distance on Wireless Signal Propagation in Indoor and Outdoor Built Sites

The effects of varying distances on wireless signal propagation in indoor and outdoor built sites is presented in this paper. In indoor and outdoor built sites the major RF signal attenuation is due to multi-path interference, signal loss (fading), and non-line of sight signal blockage. A number of mobile communication systems is currently and frequently being used in indoor environments based on IEEE 802.11b standards which is on 2.4GHz frequency ISM band at the rate of 11Mbps. To determine the effects of varying distances on signal strength at 2.457 GHz, a Spykee spy Wi-Fi robot was used as the transmitter and laptop installed with a Wi-Fi card and Spykee console software to control the robot was used as the receiver. Results showed that the signal attenuation levels increased as distances increased.

Carbonaceous Aerosol Characteristics in Outdoor and Indoor Environments of Nanchang, China, during Summer 2009

ABSTRACT A study of carbonaceous aerosol was initiated in Nanchang, a city in eastern China, for the first time. Daily and diurnal (daytime and nighttime) PM2.5 (particulate matter with aerodynamic diameter ≤2.5 μm) samples were collected at an outdoor site and in three different indoor environments (common office, special printing and copying office, and student dormitory) in a campus of Nanchang University during summer 2009 (5–20 June). Daily PM10 (particulate matter with aerodynamic diameter ≤10 μm) samples were collected only at the outdoor site, whereas PM2.5 samples were collected at both indoor and outdoor sites. Loaded PM2.5 and PM10 samples were analyzed for organic and elemental carbon (OC, EC) by thermal/optical reflectance following the Interagency Monitoring of Protected Visual Environments—Advanced (IMPROVE-A) protocol. Ambient mass concentrations of PM10 and PM2.5 in Nanchang were compared with the air quality standards in China and the United States, and revealed high air pollution levels in Nanchang. PM2.5 accounted for about 70% of PM10, but the ratio of OC and EC in PM2.5 to that in PM10 was higher than 80%, which indicated that OC and EC were mainly distributed in the fine particles. The variations of carbonaceous aerosol between daytime and nighttime indicated that OC was released and formed more rapidly in daytime than in nighttime. OC/EC ratios were used to quantify secondary organic carbon (SOC). The differences in SOC and SOC/OC between daytime and nighttime were useful in interpreting the secondary formation mechanism. The results of (1) OC and EC contributions to PM2.5 at indoor sites and the outdoor site; (2) indoor–outdoor correlation of OC and EC; (3) OC–EC correlation; and (4) relative contributions of indoor and outdoor sources to indoor carbonaceous aerosol indicated that OC indoor sources existed in indoor sites, with the highest OC emissions in I2 (the special printing and copying office), and that indoor EC originated from outdoor sources. The distributions of eight carbon fractions in emissions from the printer and copier showed obviously high OC1 (>20%) and OC2 (∼30%), and obviously low EC1−OP (a pyrolyzed carbon fraction) (<10%), when compared with other sources. IMPLICATIONS Ambient PM2.5 and PM10 in Nanchang showed serious pollution levels. OC and EC were mainly distributed in the fine particle fraction. Interestingly, daytime and nighttime carbonaceous aerosol and SOC and SOC/OC values were compared and indicated that OC was released and formed more rapidly in daytime. From analysis of the distribution of OC and EC, indoor–outdoor correlation, OC–EC correlation, and the relative contributions of indoor and outdoor sources to indoor carbonaceous aerosol, we confirmed the presence of indoor OC sources and limited indoor EC sources. Carbon fractions in emissions from the printer and copier showed obviously high OC1 and OC2 contributions and low EC1−OP percentages. The study contributes a significant reference for the control of indoor carbonaceous sources.

Influence of traffic variations on exposure to wireless signals in realistic environments

In this article, the general public daily exposure to broadcast signals and Global System for Mobile Communications (GSM) or Universal Mobile Telecommunications System (UMTS) mobile telephone signals in indoor areas is investigated. Temporal variations and traffic distributions during a day at different indoor sites in urban and rural zones are presented. The goal is to analyze the real exposure compared to the maximum assessment imposed by radio protection standards and to characterize the ratio between daily and maximum theoretical values. Hence, a realistic maximum is proposed based on the statistical analysis performed using measurements. Broadcast signals remain constant over the day so they are best fitted with a Normal distribution while the mobile telephone signals depend on the traffic demand during the day so they fit a three-Gaussian distribution model. A general mask is also constructed for underlining the maximum equivalent active traffic for different periods in the day. Also, relations between the mean values over 24 h, the realistic maximal values (at 99%) and the maximal theoretical values are presented. The realistic maximum is also presented with a sliding time average of 6 min applied to the measurements in accordance with international standards. An extrapolation factor is given for the different systems to easily assess the maximum values starting from an instantaneous measurement. The extrapolation factor is also given for a broadband measurement to estimate the maximum potential exposure during the day.

Domestic exposure to aeroallergens in Hong Kong families with asthmatic children

Indoor aeroallergen exposures increased asthma symptoms in Caucasians, but their determinants and relationship to asthma and allergy in Asians are unclear. This study investigated exposures to cat, cockroach, and Blomia tropicalis allergens in 115 Hong Kong families with asthmatic children. Patients underwent exhaled nitric oxide and spirometric measurements. Home visits were made within 2 weeks during which parents completed a standardized questionnaire. Fel d 1, Bla g 2, and Blo t 5 in dust samples collected from patients' mattresses, bedroom floors, and living room floors were measured by immunoassays. These aeroallergens were only detectable in some homes (38-55% for Fel d 1; 9-21% for Bla g 2, and 7-14% for Blo t 5). The presence of cat and/or dog was a strong determinant for Fel d 1 in all indoor sites. The timing and frequency of bedding change was associated with Bla g 2 levels, whereas the timing of bedroom floor cleaning was a consistent factor for Blo t 5 levels. Asthmatic children in families with high allergen exposure were more likely to have ≥4 wheezing attacks in preceding 12 months and exercise-induced wheezing than those with normal allergen exposure (P = 0.051 and 0.030, respectively). Mattress levels of all three allergens were also associated with severity of several allergy symptoms (P = 0.025-0.005). None of these aeroallergens correlated with exhaled nitric oxide and spirometric parameters. This study identifies determinants for cat, cockroach, and B. tropicalis levels in Hong Kong families with asthmatic children. These exposures are associated with severity of allergy symptoms.

Changes in profiles of airborne fungi in flooded homes in southern Taiwan after Typhoon Morakot

In August 2009, the historic Typhoon Morakot brought extreme rainfall and resulted in flooding which spread throughout southern Taiwan. This study compared the difference between fungal concentrations before and after the disaster in selected homes of the Tainan metropolitan area, which were hit hardest by the catastrophe. A group of 83 households available from a prior cohort established with random sampling out of a regional population in southern Taiwan was contacted successfully by telephone. Twenty-five of these reported to have suffered from floods of various degrees at this time. Around 2 weeks after the event, at which time most of the remedial process had been completed by self-efforts and public health endeavours, 14 of these 25 (56%) agreed to participate in measurements of the airborne microbial concentrations. The averages (standard deviation) of the total culturable fungal concentrations in children's bedrooms and flooded rooms were 18,181 (25,854) colony-forming units per cubic metre (CFU/m 3) and 13,440 (11,033) CFU/m 3, respectively. The airborne fungal spore levels in the 2 above-mentioned indoor sites were 221,536 (169,640) spores/m 3 and 201,582 (137,091) spores/m 3, respectively. The average indoor/outdoor ratios in the children's bedrooms were 4.2 for culturable fungi and 1.4 for fungal spores. These values were higher than the respective values measured in the same homes during the previous year: 1.1 and 0.6. In terms of the specific fungal profile, the percentages of Aspergillus spp. increased significantly in both the indoor and outdoor environments after the event. To this date, this study is among the limited research that has been conducted to quantitatively demonstrate that fungal manifestation is likely to persist in flooded homes even after seemingly robust remedial measures have been put into place. Studies to examine the potential health implications and effectiveness of better remedial technology remain much needed.

A preliminary survey of carrion breeding insects associated with the Eid ul Azha festival in remote Pakistan

In Pakistan, the three days of Islamic festival of Eid ul Azha (Eid) are characterized by millions of livestock sacrifices and availability of countless breeding resources for insects of forensic importance. Thus during Eid, December, 2008, in a Pakistani village observing 70 sacrifices, we examined postmortem insect attractions on various sacrificial products (from 23 animals), i.e., blood pools, meat, hides/skins, bones, offal and real time insect succession on goats' offal at five dump sites. Thirty five insect species were collected from 14 indoor and outdoor sites. Offal at the dump sites attracted most insect species both by taxa and in numbers, followed by hides in the court yards, meat (40-70 kg/animal) in kitchens and blood pools in the court yards. Synanthropic calliphorids and muscids were found to be exclusive indoor "first and only arrivals" in comparison to a diverse array of first day insect arrivals at dump sites including calliphorids, sarcophagids, muscids, sphaerocerids, sepsids, empidids, gryllids and formicids. Though burial is usually considered as a barricade between most insect species and carrion yet dump site A with an early burial but also earliest insect colonization showed the fastest rate of decomposition. No vertebrate scavenging at any of the offal dump sites perhaps showed their private feeding inclination, thus implying that in times of mass slaughters most of the dumped winter carrion products in human vicinities are either consumed by insects and/or are buried. Here we also suggest a high rate of fly dispersal during Eid which if true has consequences for forensic investigations in Muslim populace areas especially during the Eid.

Investigation of the Influence of Reflective Insulation on Indoor Reception in Rural Houses

We investigate the effects of reflective (metallic) insulation on indoor digital television (DTV) signal reception in rural houses. Simulation results indicate that under non-line-of-sight (NLOS) conditions, the presence of reflective insulation may significantly degrade indoor signal reception and cause a large variation of signal level inside a house. To predict the average signal level in domestic indoor sites, a simple empirical model that covers the DTV broadcast frequencies is proposed. Simulations also show that directional antennas may not necessarily improve indoor DTV signal reception.

Indoor Determinants of Endotoxin and Dust Mite Exposures in Hong Kong Homes with Asthmatic Children

Background: Domestic endotoxin enhances airway inflammation and increases asthma severity in Caucasian children, but little data are published on indoor endotoxin exposure in Asian countries. This study investigated house dust endotoxin and Der p 1 levels in Hong Kong families with asthmatic children, and their effects on asthma severity. Methods: 115 asthmatics from a pediatric clinic underwent fractional exhaled nitric oxide (FeNO) and spirometric measurements. Home visits were then made within 2 weeks, during which parents completed the International Study of Asthma and Allergies in Childhood questionnaire. Settled dust was collected from patients’ mattresses, bedroom floors and living room floors. Endotoxin and Der p 1 were measured by limulus amebocyte lysate and immunoassay, respectively. Results: Endotoxin was detectable in all locations from all families, whereas Der p 1 was detectable in 58–70% of indoor sites. Floors of both bedroom and living rooms had higher endotoxin but lower Der p 1 levels than mattresses (p < 0.001 for both). Mattress endotoxin level correlated inversely with Der p 1 level (r = –0.308, p = 0.001). Household smoker, feather bedding and vacuum cleaning were independent determinants of indoor endotoxin. Timing of last bedding change was associated with Der p 1 levels at all sites. Mattress endotoxin level was associated with frequency of wheezing episodes (p = 0.044), but neither endotoxin nor Der p 1 was associated with FeNO and spirometric parameters. Conclusions: Domestic endotoxin levels are associated with frequency of wheezing episodes in asthmatic children but not their FeNO or spirometric measurements.

Evaluation of radon levels in indoor gymnasia of Palermo (Sicily) and Sassari (Sardinia)

Background: In the last decades, there has been increased worldwide interest in the management of healthrisks from indoor radon.Methods: From 2006 to 2008, a survey on air radon levels was carried out in a total of 57 indoor gymnasiarespectively located in the urban area of Palermo (Sicily) and Sassari (Sardinia).Results: The indoor radon levels were generally low with different geometric means in the two geographicareas (14.3 Bq/m3 in Palermo and 36 Bq/m3 in Sassari, respectively). Overall, in both groups increasingvalues of radon were found during the night and the early morning, with radon concentrations significantlylower during working time than at other times. The analysis of structural parameters showed that directcontact with the soil significantly correlated with increased levels of radon in gymnasia located in Palermo’sarea (p&lt;0.05). Furthermore, higher radon levels in Sicilian structures were also associated, although notsignificantly, with lack of sumps (19.3 vs 12.9 Bq/m3), location below the ground level (18.8 vs 8.7 Bq/m3),lack of windows (25 vs 13.2 Bq/m3), presence of forced ventilation (15.5 vs 7.3 Bq/m3) and with cracks ormoisture tracks (15.7 vs 13.2 Bq/m3).Conclusions: Radon tends to accumulate in indoor sites and it’s monitoring, especially in buildings withpotentially overcrowded conditions, could be of public health interest. Mitigation measures and minimizationof the number of structural and functional risk parameters should be strongly encouraged in order to limitradon accumulation especially in countries with higher radium concentration in the soil.

Characteritization of, and health risks from, polychlorinated dibenzo- p-dioxins/dibenzofurans from incense burned in a temple

Polychlorinated dibenzo- p-dioxins/dibenzofurans (PCDD/Fs) may cause adverse health effects. However, PCDD/F emissions from burning incense in temples have rarely been addressed. This study investigates PCDD/F emissions from burning incense in a temple. The mean total PCDD/F concentrations were 72.4–82.2 pg Nm − 3 at two indoor sites; their corresponding mean total PCDD/Fs I-TEQ concentrations (0.24–0.27 pg I-TEQ Nm − 3 ) were ~ 11 times that at a background location. In air samples collected from burning incense, OCDFs accounted for approximately 90% of total PCDD/Fs at the two indoor sites and an outdoor site near the temple, while the major PCDD/Fs in incense ash were PCDDs. The total PCDD/F content and toxic equivalent value of incense ash were 617 pg g − 1 and 1.55 pg I-TEQ g − 1 , respectively. At the three sites inside/outside the temple, the air and ash samples contained the same four primary PCDD/Fs–OCDD, 1,2,3,4,6,7,8-HpCDD, OCDF and 1,2,3,4,6,7,8-HpCDF. The Cl − emission factor, which is related to the PCDD/F formation, from burning incense was 0.454 mg g − 1 . The resultant lifetime average daily dose and cancer risk for temple workers were 0.00964 pg I-TEQ day − 1 kg − 1 and 9.64 × 10 − 6 , respectively, approximately 2 times that for residents near the temple (0.00489 pg I-TEQ day − 1 kg − 1 and 4.89 × 10 − 6 , respectively). We suggest that the chlorine content in incense must be regulated, and the high risk of PCDD/F exposure from burning incense for temple workers and visitors should be of concern.

Parameterization of meteorological variables in the process of infiltration of outdoor ultrafine particles into a residential building

As part of the Brooklyn Traffic Real-Time Ambient Pollutant Penetration and Environmental Dispersion (B-TRAPPED) study, a field investigation was conducted of the mechanisms involved in infiltration of outdoor particles (0.02 microm to 1 microm) into a near-highway urban residential building. Using continuous real-time total number concentration time-series data measured simultaneously at multiple outdoor and indoor locations, the infiltration time was estimated for various indoor sites by using the cross-correlation analysis method. The effects of meteorological variables on infiltration times were also characterized at given locations. In particular, infiltration time was examined as a function of outdoor mean rooftop wind speed. Outdoor and indoor temperature and relative humidity were also investigated in relation to infiltration times. Our results showed that outdoor wind speed was the dominant meteorological parameter affecting the infiltration rate, but no correlation was found with temperature. The outdoor-indoor PM concentration ratio was found to be significantly different for the first and second floors of the test building. Finally, we determined the effectiveness of a protective shelter-in-place area inside the building by calculating infiltration times into the area. We found that the shelter-in-place area offered some protection against the infiltrating particles because of increased attenuation of the outdoor concentration.

Parallel Time-Domain Full-Wave Analysis and System-Level Modeling of Ultrawideband Indoor Communication Systems

This paper demonstrates the application of a high-order finite-difference time-domain (FDTD) technique to indoor microwave ultrawideband channel modeling with a two-fold purpose. First, the advantages of both serial and parallel versions of the technique compared to the conventional FDTD are pointed out. It is also shown that the results of this full-wave analysis can be translated from the electromagnetic field level to the system level, to produce simplified, physics-based, site-specific channel models. In particular, the parameters of well-established measurement-based models are determined for a specific indoor site, by means of our electromagnetic simulation. Moreover, the proposed technique is coupled with the Monte-Carlo method to characterize the capacity of a time-hopping pulse position modulation multiple access system. Hence, a connection between the field analysis of a channel and its system-level description is made, establishing the usefulness of this work for performance projections, optimization and compatibility studies of ultrawideband communication schemes and network architectures.

A novel approach to investigating indoor/outdoor pollution links: Combined magnetic and PAH measurements

In a preliminary study, paired indoor and outdoor air sampling was conducted at three locations around the city of Lancaster, UK to examine the influence of combustion sources on air quality by measuring particulate concentrations, particulate magnetic properties and polyaromatic hydrocarbons (PAHs). With one exception (an indoor suburban air sample), outdoor air samples had higher total suspended particulates (TSP), particle-bound PAH concentrations and magnetic remanence (IRM) values. IRM values were highest for the week-day, outdoor city centre samples and then declined in the sequence: Sunday, city centre > suburban/residential > Lancaster University campus. These data indicate traffic as the major particle-bound PAH, particulates and magnetic source, particularly as sampling was conducted during July in the absence of any space heating. The indoor air samples revealed a wide variation in pollutant concentrations, characterised by higher vapour levels of 2–3 ring PAHs, variable TSP concentrations and variable but generally low IRMs. The differences in PAH concentrations, TSP and IRMs between outdoor and indoor environments indicate limited ingress of outdoor air pollutants to the indoor environment in this study. Our combined PAH and magnetic data identify specific and distinctive indoor pollution signals for each of our sampled sites, reflecting distinct sources. One site, the suburban house, has anomalously high IRM, TSP and particle-bound PAHs. A possible source for these is a cast-iron, wood-burning stove (even though not lit). The city centre indoor site is characterised by high TSP and very low IRMs but high values of the magnetic ratio of anhysteretic remanence:saturation remanence, indicative of ultrafine (sub-micrometre) magnetic grain sizes. The source for this city centre indoor signature is unidentified but may reflect the occupant smoking and/or lighting candles. The indoor campus sample was affected by loss-on-ignition procedures carried out in a teaching laboratory. The combined PAH and magnetic analyses thus provide a sensitive and discriminatory means of identifying outdoor, traffic-derived pollution, and of discriminating between different types of indoor pollution.

Monitoring of volatile organic compounds in non-residential indoor environments

A weekly monitoring campaign of volatile organic compounds (VOC), with single sampling of 24 h, was carried out in non-residential indoor environments such as libraries, pharmacies, offices, gymnasiums, etc., in order to evaluate the VOC concentrations to which people are exposed. Moreover, an outdoor sample was coupled to each indoor site to point out the influence of indoor sources. They were sampled with Radiello diffusive samplers for thermal desorption and analyzed by GC-MS. As already described in other papers, the VOC levels of most of the indoor sites were higher than that observed in the corresponding outdoor sites. For example, some sites showed a level of pollution that is ten times higher than their corresponding outdoor site. The monitored environments that had higher concentrations of the investigated VOC were the pharmacies, a newspaper stand, a copy center, and the coffee shops. Analysis of the weekly average concentrations of each pollutant and the use of literature allowed pointing out some site-specific characteristics that singled out possible sources of VOC. These results were verified analyzing the indoor-outdoor ratio (I/O) too. Newspaper stands were characterized by very high concentrations of toluene and pharmacies were characterized by high concentrations of aromatic compounds. Indoor air pollution caused by volatile organic compounds (VOC) might affect human health at home as well as in public and commercial buildings. The main VOC sources in indoor environments are human activities, personal care products, smoking, house cleaning products, building products, and outside pollution. To preserve human health it is necessary to evaluate the average concentrations of VOC to which people are exposed and to identify the main sources of indoor pollution by means of suitable indoor monitoring campaigns in several environments. These investigations allow pointing out the characteristic critical situations of some indoor environments or some other types of environments.

Development of ACTION! Wellness Program for Elementary School Personnel

The prevalence of overweight and obesity has increased dramatically in the adult population over the past 2 decades. Almost two-thirds of the adult population works outside the home; thus, interventions implemented at the worksite are viable for obesity reduction. Elementary schools are worksites that have a number of resources that can encourage a healthy lifestyle. The purpose of this paper is to describe the formative research activities and how these were used to design the ACTION! Wellness Program for Elementary School Personnel. Formative data were collected using focus groups, a school survey, and an environmental audit. Focus groups were conducted in three elementary schools, whereas the school survey and environmental audit were collected in 24 elementary schools. The intervention was then tested as a pilot study in one school to determine feasibility and receptivity and refine its components. Participants in the focus groups indicated that most had experience with trying to lose weight, some had positive social support, and most had little free time at school; however, most were very receptive to having a weight control intervention program at their school. Eighteen (75%) of the schools had snack vending machines on the school site, and all had cold drink machines. All 24 schools had at least one indoor site that could be used for physical activity programs. All schools were in neighborhoods conducive for walking. ACTION! will take advantage of the school resources in implementing an environmental intervention to reduce overweight and obesity. This paper describes the progression of events that led to the final trial.

Evaluation of Human Health Risks From Exposures to Four Air Pollutants in the Indoor and the Outdoor Environments in Tokushima, and Communication of the Outcomes to the Local People

The Law concerning Reporting etc., of Releases to the Environment of Specific Chemical Substances, and Promoting Improvement in Their Management (the so‐called Pollutant Release and Transfer Register Law or the PRTR Law) was promulgated in Japan in 1999. Estimated amounts of the specific chemical substances released from their major emission sources to local environments are publicly available by law. Concentrations of benzene, toluene, xylene (i.e., volatile organic compounds or VOCs) and formaldehyde specified by law were measured in different seasons from 2003 to 2005 both at outdoor and indoor sites within the Tokushima University campus and in a nearby local area to estimate their human exposures. There were no substantial differences between the indoor and the outdoor concentrations of benzene, toluene, and xylene. Higher concentrations observed for formaldehyde in the indoor environment than in the outdoor environment in the 2003 winter season could be explained by the fact that there was renovation of the building nine months before the measurement. The exposure data obtained were used to evaluate the possible human health risks of these four chemicals by referring to their health criteria. The results indicated that the overall risks from the exposures to these chemicals both in the indoor and the outdoor environments were not significantly high even if fluctuations are taken into account. The results of our evaluation were released on the university website and also presented and discussed at a public meeting and three PRTR data seminars in the local society.

Physiological state of Aedes (Stegomyia) aegypti mosquitoes captured with MosquiTRAPs™ in Mirassol, São Paulo, Brazil

We examined the best location in a house to install MosquiTRAPs, sticky ovitraps that attract and capture Aedes aegypti females and investigated the physiological state of captured female mosquitoes. The study was performed in a twenty-block area in Mirassol, São Paulo State, Brazil, in which five blocks were randomly chosen for MosquiTRAP installation. In each block, four houses were selected for the installation of eight traps: four indoors (bedroom, living room, bathroom, and kitchen) and four outdoors in the shade (two at the front of the house and two in the backyard). These houses were visited over an eight-week period. The outdoor MosquiTRAPs captured five times more females than indoor traps and appeared to be the best places to install MosquiTRAPs. There were no significant differences among indoor sites or among outdoor sites with respect to the number of females captured. The capacity of the MosquiTRAP to capture a large number of gravid Ae. aegypti females reinforces its potential as an entomological surveillance tool in dengue control programs.

Indoor and outdoor submicrometer particles: Exposure and epidemiologic relevance (“the 3 indoor Ls”)

Airborne particles represent a very important pollutant with respect to healthy housing conditions. The snag is that in lack of indoor data epidemiological studies focusing on submicron and ultrafine (<100 nm in diameter) particles are usually forced to use outdoor particle concentrations only. On the other hand it is known that people spend most of their time indoors. The aim of this paper is therefore to give a short comprehensive overview of the indoor/outdoor problem with regard to submicron and ultrafine particles, investigating how indoor particle size distributions correlate with outdoor concentrations in the absence of significant indoor sources. In the absence of a major indoor source, total indoor particle number concentrations were always lower than outdoor concentrations. The highest ratios between indoor and outdoor concentrations tend to correlate with lower rather than higher total outdoor particle number concentrations. Concentration ratios depend on particle size. Time lags of the correlation coefficients between the concentrations of indoor and outdoor particles of different diameters have been determined to assess the time the particles need to enter the indoor site through closed modern-type windows. Typical lag times of 0.5-3 h between somewhat smaller indoor particles and somewhat larger outdoor particles have been observed. To assess the resulting particle burden for humans, a suitably weighted average emphasizing indoor aerosol particles must be used. To classify the health effects of particles of different diameters, different decreases of particle number concentrations depending on the particle sizes must be taken into account if indoor concentrations cannot be measured and outdoor concentrations are used in place of indoor measurements. In urban areas, ultrafine particles originate primarily from rapidly increasing traffic, which is the dominating source at many urban sites. The influence of traffic on outdoor and indoor concentrations is therefore of special interest.

From bench top to presentation in five days: DNA sequencing research projects for summer workshops or undergraduate teaching labs

We present two DNA sequencing research projects that were carried out by high school science teachers during the Summer Teachers’ Workshop at Amherst College. One group of eight teachers investigated the genetic basis of human skin pigmentation, while a second group of seven teachers sampled the microbial diversity of indoor and outdoor sites at Amherst College. PCR was used to amplify specific sequences of human or microbial DNA, respectively, and each group obtained DNA samples that were of sequenceable quality in three days. Samples were sent to Cornell University’s Biotechnology Resource Center for sequencing, and sequence analyses and alignments were performed using the ChromasLite and Lasergene software packages for PCs. BLAST searches of the NCBI databases were also performed. Each research team presented the results of their study with a group Power Point presentation on the final morning of the workshop. Both research projects can be easily modified for a multiple-week course. Thus, they are suitable for undergraduate lab courses in genetics, genomics or evolution. The microbial diversity project is also suitable for undergraduate courses in microbiology. (Workshop funding received from the Howard Hughes Medical Institute.)

Dustborne Alternaria alternata antigens in US homes: Results from the National Survey of Lead and Allergens in Housing

Alternaria alternata is one of the most common fungi associated with allergic disease. However, Alternaria exposure in indoor environments is not well characterized. The primary goals of this study were to examine the prevalence of Alternaria exposure and identify independent predictors of Alternaria antigen concentrations in US homes. Data for this cross-sectional study were obtained from the National Survey of Lead and Allergens in Housing. A nationally representative sample of 831 housing units in 75 different locations throughout the United States completed the survey. Information on housing and household characteristics was obtained by questionnaire and environmental assessments. Concentrations of A alternata antigens in dust collected from various indoor sites were assessed with a polyclonal anti-Alternaria antibody assay. Alternaria antigens were detected in most (95% to 99%) of the dust samples. The geometric mean concentration, reflecting the average Alternaria concentration in homes, was 4.88 microg/g (SEM, 0.13 microg/g). In the multivariable linear regression analysis, the age of the housing unit, geographic region, urbanization, poverty, family race, observed mold and moisture problems, use of de-humidifier, and presence of cats and dogs were independent predictors of Alternaria antigen concentrations. Less frequent cleaning and smoking indoors also contributed to higher Alternaria antigen levels in homes. Exposure to A alternata antigens in US homes is common. Antigen levels in homes are influenced not only by regional factors but also by residential characteristics. Preventing mold and moisture problems, avoiding smoking indoors, and regular household cleaning may help reduce exposure to Alternaria antigens indoors.