Increasing stair climbing in a train station: The effects of contextual variables and visibility

Accumulation of physical activity during daily living is a current public health target that is influenced by the layout of the built environment. This study reports how the layout of the environment may influence responsiveness to an intervention. Pedestrian choices between stairs and the adjacent escalators were monitored for 7 weeks in a train station (Birmingham, UK). After a 3.5 week baseline period, a stair riser banner intervention to increase stair climbing was installed on two staircases adjacent to escalators and monitoring continued for a further 3.5 weeks. Logistic regression analyses revealed that the visibility of the intervention, defined as the area of visibility in the horizontal plane opposite to the direction of travel (termed the isovist) had a major effect on success of the intervention. Only the largest isovist produced an increase in stair climbing. Additionally, stair climbing was more common during the morning rush hour and at higher levels of pedestrian traffic volume. The layout of the intervention site can influence responsiveness to point-of-choice interventions. Changes to the design of train stations may maximize the choice of the stairs at the expense of the escalator by pedestrians leaving the station.     

Aerosol chemistry and the effect of aerosol water content on visibility impairment and radiative forcing in Guangzhou during the 2006 Pearl River Delta campaign

Optical and chemical aerosol measurements were obtained from 2 to 31 July 2006 at an urban site in the metropolitan area of Guangzhou (China) as part of the Program of Regional Integrated Experiment of Air Quality over Pearl River Delta (PRIDE-PRD2006) to investigate aerosol chemistry and the effect of aerosol water content on visibility impairment and radiative forcing. During the PRIDE-PRD2006 campaign, the average contributions of ammonium sulfate, organic mass by carbon (OMC), elemental carbon (EC), and sea salt (SS) to total PM_2.5 mass were measured to be 36.5%, 5.7%, 27.1%, 7.8%, and 3.7%, respectively. Compared with the clean marine period, (NH₄)₂SO₄, NH₄NO₃, and OMC were all greatly enhanced (by up to 430%) during local haze periods via the accumulation of a secondary aerosol component. The OMC dominance increased when high levels of biomass burning influenced the measurement site while (NH₄)₂SO₄ and OMC did when both biomass burning and industrial emissions influenced it. The effect of aerosol water content on the total light-extinction coefficient was estimated to be 34.2%, of which 25.8% was due to aerosol water in (NH₄)₂SO₄, 5.1% that in NH₄NO₃, and 3.3% that in SS. The average mass-scattering efficiency (MSE) of PM₁₀ particles was determined to be 2.2 ± 0.6 and 4.6 ± 1.7 m² g⁻¹ under dry (RH < 40%) and ambient conditions, respectively. The average single-scattering albedo (SSA) was 0.80 ± 0.08 and 0.90 ± 0.04 under dry and ambient conditions, respectively. Not only are the extinction and scattering coefficients greatly enhanced by aerosol water content, but MSE and SSA are also highly sensitive. It can be concluded that sulfate and carbonaceous aerosol, as well as aerosol water content, play important roles in the processes that determine visibility impairment and radiative forcing in the ambient atmosphere of the Guangzhou urban area.     

Changes in visibility with PM2.5 composition and relative humidity at a background site in the Pearl River Delta region

In fall–winter, 2007–2013, visibility and light scattering coefficients(b sp) were measured along with PM_(2.5)mass concentrations and chemical compositions at a background site in the Pearl River Delta(PRD) region. The daily average visibility increased significantly(p 0.01) at a rate of 1.1 km/year, yet its median stabilized at ~13 km. No haze days occurred when the 24-hr mean PM_(2.5)mass concentration was below 75 μg/m~3. By multiple linear regression on the chemical budget of particle scattering coefficient(b sp), we obtained site-specific mass scattering efficiency(MSE) values of 6.5 ± 0.2, 2.6 ± 0.3, 2.4 ± 0.7 and 7.3 ± 1.2 m2/g,respectively, for organic matter(OM), ammonium sulfate(AS), ammonium nitrate(AN) and sea salt(SS). The reconstructed light extinction coefficient(b ext) based on the Interagency Monitoring of Protected Visual Environments(IMPROVE) algorithm with our site-specific MSE revealed that OM, AS, AN, SS and light-absorbing carbon(LAC) on average contributed 45.9% ± 1.6%,25.6% ± 1.2%, 12.0% ± 0.7%, 11.2% ± 0.9% and 5.4% ± 0.3% to light extinction, respectively.Averaged b ext displayed a significant reduction rate of 14.1/Mm·year(p 0.05); this rate would be 82% higher if it were not counteracted by increasing relative humidity(RH) and hygroscopic growth factor(f(RH)) at rates of 2.5% and 0.16/year-1(p 0.01), respectively, during the fall–winter, 2007–2013. This growth of RH and f(RH) partly offsets the positive effects of lowered AS in improving visibility, and aggravated the negative effects of increasing AN to impair visibility.     

Species of the Month: Anti-Whaling,Mediated Visibility,and the News

Paul Watson, founder of the Sea Shepherd Conservation Society and captain of anti-whaling ship the Steve Irwin, has emerged as one of the world's most visible environmental protesters. This essay, based in part on a long interview with Watson in Australia in 2009, analyzes his mediated visibility and thus capacity to participate in public debate by isolating various components of his strategic activities under four themes: mediated protest, symbolic power, media practices, and celebrity. It argues that Watson's visibility involves a complex flow of information and meanings across various “old” and “new” media form, but remains reliant on news media. Thus, despite his generally astute media practices and strategies, Watson's visibility is contingent on a set of professional practices and logics unlikely to provide sustained news access or long-term legitimacy to a political “outsider.”     

Stingless bee response to spider webs is dependent on the context of encounter

In the course of their foraging bouts, bees frequently encounter spider webs among the vegetation. The ability to see and avoid these webs is vital for the success of the individual bee’s foraging bout. In this study, we report on the response of stingless bees (Trigona carbonaria) towards the webs of the St. Andrew’s Cross spider (Argiope keyserlingi). We studied the ability of bees to avoid webs in different contexts: when bees were on their foraging path or when they were returning to the hive as well as when they were flying North or South. We show that the probability of a bee being able to avoid a web depends on the context of the bee’s flight rather than the visual appearance of the web. Furthermore, the presence of the spider seems to alert the bee to the web, resulting in bees being more able to avoid capture. We show, specifically, that the probability of being captured is higher when the bee is returning to the hive compared with when the bee is foraging. The likelihood of avoiding a web is also influenced by the compass direction of the flight, although to a lesser extent. Our results indicate that the context of the predator–prey encounter has a significant influence on a bee’s ability to escape interception by a spider web.     

灰霾天气不同粒径的颗粒物污染特征分析

利用宁波市北仑区PM10、PM2.5和PM1的监测数据及与之对应的能见度监测结果,对影响灰霾天的颗粒物的污染特征进行了系统研究,结果表明,颗粒物粒径对灰霾天的形成和能见度的影响程度差异明显,且3种粒径的颗粒物质量浓度与能见度之间线性关系密切。     

PWD22能见度仪监测上海市水平能见度的试验研究

利用PWD22能见度仪监测数据,分析了上海市2008年—2009年能见度日变化规律和四季逐日变化特征,以及能见度和混合层高度(MLH,Mixed Layer Height)、空气污染指数(API)及气象要素(相对湿度、风速、温度)的相关性。结果表明,能见度一峰一谷日变化特征明显,峰值出现在14:00~16:00,谷值出现在6:00~8:00。能见度与MLH相关性显著,与温度最差。能见度和气溶胶光学厚度(AOT)线性拟合呈负相关关系,且夏季相关性最显著,冬季最差。     

能见度仪检测实验室建设的探讨

对能见度仪检测实验室建设进行了探讨。简述了能见度仪检测实验室的技术特性;从能见度仪标准器建设、环境模拟和检测方法 3方面进行了讨论;提出了在能见度环境模拟试验方舱内实现气象光学视程3 km以下能见度仪检测的方案。     

The effect of workers' visibility on effectiveness of intervention programs: supervisory-based safety interventions

INTRODUCTION: This paper discusses an organizational change intervention program targeting safety behaviors and addresses important considerations concerning the planning of organizational change. Using layout of the plant as a proxy for ease of daily leader-member interaction, the effect of workers' visibility on the effectiveness of supervisory-based safety (SBS) interventions is examined. Through a reinforcement-learning framework, it is suggested that visibility can affect supervisors' incentive to interact with subordinates regarding safety-related issues. METHOD: Data were collected during SBS intervention studies in five manufacturing companies. RESULTS: Results suggest a reinforcement cycle model whereby increased visibility generates more frequent exchanges between supervisors and employees, resulting in improved safety behavior among employees. In turn, employees' safer behavior reinforces continued supervisory safety-related interaction. CONCLUSION AND IMPACT ON INDUSTRY: Visibility is an important moderator in supervisory based safety interventions, and can serve to increase workplace safety. Implications of these findings for safety are discussed.     

Humidity and PM2.5 composition determine atmospheric light extinction in the arid region of northwest China

Atmospheric visibility can directly reflect the air quality. In this study, we measured water-soluble ions (WSIs), organic and element carbon (OC and EC) in PM_2.5 from September 2017 to August 2018 in Urumqi, NW China. The results show that SO₄^2?, NO₃^? and NH₄⁺ were the major WSIs, together accounting for 7.32%–84.12% of PM_2.5 mass. Total carbon (TC=OC+EC) accounted for 12.12% of PM_2.5 mass on average. And OC/EC > 2 indicated the formation of secondary organic carbon (SOC). The levels of SO₄^2?, NO₃^? and NH₄⁺ in low visibility days were much higher than those in high visibility days. Relative humidity (RH) played a key role in affecting visibility. The extinction coefficient (b_ext) that estimated via Koschmieder formula with visibility was the highest in winter (1441.05 ± 739.95 Mm^?1), and the lowest in summer (128.58 ± 58.00 Mm^?1). The b_ext that estimated via IMPROVE formula with PM_2.5 chemical component was mainly contributed by (NH₄)₂SO₄ and NH₄NO₃. The b_ext values calculated by both approaches presented a good correlation with each other (R² = 0.87). Multiple linear regression (MLR) method was further employed to reconstruct the empirical regression model of visibility as a function of PM_2.5 chemical components, NO₂ and RH. The results of source apportionment by Positive Matrix Factorization (PMF) model showed that residential coal combustion and vehicle emissions were the major sources of b_ext.