Elisabeth Dalholm Hornyánszky

Ebola: Improving the Design of Protective Clothing for Emergency Workers Allows Them to Better Cope with Heat Stress and Help to Contain the Epidemic

It is a complex task to find optimal protective clothing to prevent the spread of Ebola virus disease (Martin-Moreno et al., 2014; Ryschon, 2014). The fear of getting infected is an obstacle for recruiting healthcare workers. In addition, the current design of protective clothing might curtail their working capacity severely in the hot and humid climate of West Africa and, in addition, paradoxically increase the risk of infection. Emergency work in full protective clothing including respiratory mask may lead to extreme heat stress in the hot climates resulting in shortened work time, dehydration, reduced professional judgement, and exhaustion. This increases risk of infection of health stuff (WHO, 2014). In Monrovia, Liberia, daytime maximum temperatures in the end of the year often reach 30–31°C, and the temperatures will be higher January to May, the hot season (Kjellstrom et al., 2014; http://climatechip.org/). In order to manage this heat stress, the workers need breaks (Kjellstrom et al., 2009). This leads to a frequent need to remove the protective gear, which involves an increased risk of infection. The multiple steps to remove the suit can take up to 30min (Kitamura, 2014). The modified Predicted Heat Strain (ISO 7933, 2004) model was used to indicate the expected work times (Fig. 1). The estimation was made based on the following assumptions. Standard man was chosen for the model calculations. Medium heavy activity (300W) was taken as the average work rate. The core temperature limit to cease such emergency work was set to 38.5°C. Three clothing types with different moisture permeability (i m) were selected for comparison: an impermeable outer layer (i m = 0.00), a semipermeable outer layer (i m = 0.07), and a relatively tight but still permeable outer layer (i m = 0.20). The basic clothing insulation in all cases was theoretically taken as 1 clo (0.155 m2K W−1) for comparative purposes. In all air temperature conditions, the other environmental factors were kept constant. Ambient water vapour pressure was set to 3.0 kPa, air velocity/body motion was 1 m s−1, and there was assumed no radiation effect present (work indoors or in shade). 1 Continuous work times for a work rate of 300W at different air temperatures before reaching a core temperature limit at 38.5°C in clothing with different moisture permeability (i m). The chosen work load in impermeable and semipermeable clothing allows 40min or shorter exposure during the hottest periods (Fig. 1) until the core temperature exceeds the suggested safe limit for occupational exposure. Higher core temperature is associated with decreased mental performance and increased misjudgement and mistakes (O’Neal and Bishop, 2010). Maximizing the moisture permeability and minimizing the clothing layers worn beneath the protective gear, provided that it should be resistant to penetration by body fluids, is a simple way of preventing heat stress and increasing the time spent inside the gear. However, dehydration and water intake must also be considered during extended exposures. A heat stress management program including rehydration should be an essential part of the overall health and safety program in any case. A desirable addition would be personal cooling used inside the protective clothing, such as cooling vests with ice or phase change materials (PCMs; Gao, 2014) or filtered ventilated coveralls (Kuklane et al., 2012). This may prolong working time to about 2h and reduce the number of gear changes per day. With 2-h work time in protective gear, the number of required personnel could be halved with possible decrease in contaminated waste. The final choice of the cooling method depends on specific air temperature and humidity. Increasing air temperature and, especially, humidity do reduce the effectiveness of air cooling and increase the benefits of PCM products. The use of PCMs requires freezers or cool areas for solidification after use. Cooling vests with ice are the cheapest and electricity for freezers is required. Power is one of the basic resources to provide healthcare and to cope with epidemics. Otherwise, the other types of PCM, e.g. Glauber’s salt or organic hydrocarbons/wax, with melting/solidifying temperature at about 28°C are available. For workers’ recovery after heat exposure, a room with air temperature below 27°C is recommended. The room or connected facilities could be used for PCM solidification storage. If still unavailable, then the melted PCM can be solidified in a relatively cooler water bath (using underground/well water, etc.), in an underground cave or in a cooler area during night. The higher the melting temperatures are, the less effective cooling is. However, if the temperature gradient is about 6°C or greater, the PCM can still provide a cooling effect. Considering cooling effect in ventilated garments, the provided air flow should be above 100 l min−1. There are filtered fan systems available on the market that manage the flows up to and above 200 l min−1 with the battery power lasting at least 5–8h (recharging takes about 2h). Ventilated systems (positive pressure suits) may allow even drinking water in the suit and that may prolong the work time even more. Table 1 gives a rough cost comparison of the present and a possible future protective clothing system based on 1-day (8-h) shift. It takes into account only the equipment cost. Estimation is based on the work time predictions given in Fig. 1 for the hottest work periods, i.e. 30min for the impermeable set and 2h for the new system that prolongs work period by higher permeability or by use of a cooling device. In both cases, similar final core temperatures are expected to limit the exposure. Also, it is expected that both sets take 30min for dressing, 30min for undressing, and require 30min for recovery between the work periods. As it can be seen the equipment cost of a new, theoretically even a 10 times more expensive solution is almost 3 times higher for a day. Table 1. Comparison of the equipment cost of the present and a possible, 10 times more expensive protective clothing system based on 1-day (8-h) shift. Assumed work time is 30min for present and 2h for the new system. In both cases, expected donning, doffing, ... Simultaneously, there are also other benefits with an actively cooling clothing system. The personnel need to cover one workstation is halved. The personnel have even extra time (about 30min) between the shifts to help with any other tasks or for additional recovery. Due to fewer times of dressing–undressing (16 + 16 times 30min versus 4 + 4 times 30min for present respective new system), there is also less need for assistance and disinfection during these periods. There will be less contaminated waste or fewer amounts of products to be cleaned. The new systems are meant to be reusable (extra costs for decontamination procedures have to be considered) compared to present, supposedly disposable systems, and already 2.5 times reuse will even up the equipment costs at the estimated prices. Infection risks are diminished due to the reduced need for undressing and cleaning procedures. In conclusion, reducing the risk of infection among the front-line healthcare workers and allowing a doubling of their work capacity could be a critical factor to successfully contain the epidemic. Considering that this epidemic is not the last, and with warmer climate both the epidemics are expected becoming more frequent, and conditions to fight them more severe (IPCC, 2013), then the testing and evaluation for selection of the optimal equipment is required long before missions are set out.

Challenges of using air conditioning in an increasingly hot climate

At present, air conditioning (AC) is the most effective means for the cooling of indoor space. However, its increased global use is problematic for various reasons. This paper explores the challenges linked to increased AC use and discusses more sustainable alternatives. A literature review was conducted applying a transdisciplinary approach. It was further complemented by examples from cities in hot climates. To analyse the findings, an analytical framework was developed which considers four societal levels—individual, community, city, and national. The main challenges identified from the literature review are as follows: environmental, organisational, socio-economical, biophysical and behavioural. The paper also identifies several measures that could be taken to reduce the fast growth of AC use. However, due to the complex nature of the problem, there is no single solution to provide sustainable cooling. Alternative solutions were categorised in three broad categories: climate-sensitive urban planning and building design, alternative cooling technologies, and climate-sensitive attitudes and behaviour. The main findings concern the problems arising from leaving the responsibility to come up with cooling solutions entirely to the individual, and how different societal levels can work towards more sustainable cooling options. It is concluded that there is a need for a more holistic view both when it comes to combining various solutions as well as involving various levels in society.

Exchange of knowledge and expertise for sustainable urban development: experiences from cross-disciplinary and transnational cooperation between practitioners and researchers in the Öresund region

This article presents the work of a cross-disciplinary Danish–Swedish collaboration project. The aim was to create best practices for sustainable urban settlements in the Öresund Region. Researchers and practitioners from municipalities in the region evaluated local and European projects for new urban areas and urban renewal using six concepts – identity, density, diversity, landscape, resources and governance. These concepts were also used for creating scenarios for four case areas and for a general discussion of sustainable urban environments summarised in a toolbox. The cooperation revealed diverse approaches to urban renewal and the significance of local legislation and financial prerequisites for renewal processes.This article presents the work of a cross-disciplinary Danish–Swedish collaboration project. The aim was to create best practices for sustainable urban settlements in the Oresund Region. Researchers and practitioners from municipalities in the region evaluated local and European projects for new urban areas and urban renewal using six concepts – identity, density, diversity, landscape, resources and governance. These concepts were also used for creating scenarios for four case areas and for a general discussion of sustainable urban environments summarised in a toolbox. The cooperation revealed diverse approaches to urban renewal and the significance of local legislation and financial prerequisites for renewal processes.

Correspondence to the supplementary opinions on alternative cooling technologies in hot climate

At present, air conditioning (AC) is the most effective means for the cooling of indoor space. However, its increased global use is problematic for various reasons. This is a correspondence to the supplementary opinion provided by Dr. Bin Yang, Dr. Stefano Schiavon, and Dr. Faming Wang to our paper titled “Challenges of using air conditioning in an increasingly hot climate.” The paper explored the challenges linked to increased AC use and discusses more sustainable alternatives. The supplementary opinion provides a great technical complement to our paper. However, there is a need for a more holistic view both when it comes to combining various solutions and involving various levels in society.