Personal protective equipment use during COVID-19 pandemic and associated waste management in households in Sri Lanka

The use of personal protective equipment (PPE) is compulsory when accessing public places due to the ongoing COVID-19 pandemic in many countries. Facemasks are the most common PPE used, however, some people use face shields and gloves. Frequent hand sanitizing is also recommended aiming to control the spread of the disease. All these activities generate a large amount of plastic waste daily. In Sri Lanka, it is estimated that 12 million facemasks are used daily, while 0.22 million gloves and 0.29 million face shields are used. Out of 12 million facemasks, 10 million are surgical or N95 masks. In addition, 0.79 million sanitizer bottles are used in a day, leaving empty plastic bottles. The most common method of disposing of facemasks in Sri Lanka is open burning by the users at their homes (55%). The rate of burning is comparatively low for other PPE. Although nearly 30% of people handover used facemasks to the municipal solid waste collection, there are no special precautions taken for separate collection and safe disposal. Guidelines are in place for handling healthcare waste generated in households under self-quarantine, but they are not applied for PPE waste generated in other households. Major drawbacks in PPE waste management is identied and mitigation measures were proposed. The estimate of waste plastics generated due to PPE use is 88.5 tonnes per day in the country. Energy recovery via pyrolysis may be a viable alternative to landlling and affordable for developing countries. PPE. on collecting on of face face socio-demographic


Introduction
The COVID 19 pandemic condition changed many aspects of human life. Travel restrictions, social distancing and lockdown of countries or cities were exerted to control the spread of the disease by many governments around the world (Selvaranjan et al. 2021). However, since the complete lockdowns were unable to be extended for prolonged periods, the general public was requested to use Personal Protective Equipment (PPE) and engage in economic and any other necessary activities. Facemasks are the main PPE in use to control of the spread of COVID-19 from person to person. Nevertheless, use of gloves, face shields, sanitizers has also been increased to reduce community spread of the disease (Selvaranjan et al. 2021;Zand and Heir 2021). Almost all of them are usable for a short period and made of polythene and plastic, hence leaving heaps of non-degradable waste (Abbasi et al. 2020;Selvaranjan et al. 2021). Hence, global attempts were made to estimate the generation of waste due to excessive PPE use because of global pandemic condition and made proposals for better waste management practices (Abbasi et al. 2020;Nzediegwu and Chang 2020;Sangkham 2020;Al-Omran et al. 2021;Selvaranjan et al. 2021). In particular, the focus of most of the previous research has been mainly single-use facemasks (Eg: Nzediegwu and Chang 2020;Selvaranjan et al. 2021;Torres and De-La-Torre 2021), while health recommendations guide people to use face shields, gloves, and hand sanitizers depending on the requirement. Hand sanitizer usage was an uncommon practice in Sri Lanka before the COVID-19 situation. However, the use of hand sanitizers skyrocketed during the pandemic, thus leaving heaps of plastic bottles in the waste stream. Although not widespread, in addition to medical staff, supermarket workers, food and bakery sector workers, etc., who handle the money and food started to wear plastic gloves. Face shield usage has also become a practice common among young children and senior citizens. However, a segment of younger adults has also started to use them. Therefore, this study focuses on the increase in waste due to all of these activities. Meanwhile, many studies assume that facemask use is one per day or two per day, but have not quanti ed it with data collected from individuals (ex: Nzediegwu and Chang 2020;Sangkham 2020). In developing countries, where there are affordability issues, usage patterns of PPE might be in uenced by income; hence we approached to collect data from general public on the use of PPE during a month and the frequency of using a new facemask.
There are two main concerns on management of waste associated with PPE use. First, this waste may contribute the spread of the disease if safe disposal practices were not adopted because viruses can remain alive on the PPE materials for several days (Kampf et al. 2020;Nzediegwu and Chang 2020). The second is most of this waste is single use plastics; hence release of micro-plastics into the environment when they are degraded. This is more prolonged impact (Abbasi et al. 2020). Therefore, many studies focus on PPE waste management and disposal methods. Many studies report improper waste disposal practices by general public such as roadside dumping, abandoned face masks on ground, entering them into marine environment etc. (Akhbarizadeh et al. 2021;Selvaranjan et al. 2021;Torres and De-la-Torre 2021) and open dumping and open burning of collected waste, in developing countries (Benson et al. 2021). Further, research studies report on COVID 19 related biomedical waste management mainly focus on contaminated waste generated in hospitals and other healthcare facilities, than in household level (Sangkham 2020;Al-Omran et al. 2021). However, there is a high possibility that PPE associated waste discarded by households may contaminate with the virus.
In global rich countries, household PPE related waste disposal may not an issue, because of well-established municipal solid waste management practices and availability of sanitary land lling or incineration of municipal solid waste (Nzediegwu and Chang 2020). However, regarding developing countries, which have poor solid waste management systems, household waste management is a signi cant issue even under normal circumstances. Hence, developing countries are in a more vulnerable situation in pandemic because solid waste collection is not well established and waste disposal techniques are not always environmentally safe and sound (Nzediegwu and Chang 2020). In addition, the use of manual labor in the waste collection is high in developing countries hence exposing human into probably contaminated PPE (Nzediegwu and Chang 2020). Therefore, under pandemic conditions, the fate of PPE related waste generated in household level has a signi cant impact on the country's environment and public health.
Therefore, this study aims to estimate PPE usage associated waste generation thorough collected data and investigate disposal methods used by households in a developing country in South Asia. Further, study evaluates the application of waste disposal guidelines in the country and identi es major drawbacks.

Methodology
The study is based on a questionnaire survey. The questionnaire was distributed via email and social networks using the referral-sampling method. People living in all nine provinces of Sri Lanka participated in the survey and the participation was entirely voluntary. Care was taken to reach all income groups because income determines the affordability of PPE. The study was focused on collecting data on the number of face masks, face shields, gloves, and sanitizer bottles utilized by a family during a month and the disposal method used for each item, separately. In addition, province of residence, family income, number of family members, and number of people who need to go out regularly for economic activities as well as socio-demographic characteristics of the respondent (gender and age) are also included. The questionnaire was conducted during April -September 2021. The sample size required for this survey was determined according to the suggestion of Kotrlik and Higgins (2001). Accordingly, when population size is more than 100000, approximate sample size required is 400. Questionnaire was conducted with 851 respondents for this study.
Estimation of daily use of PPE Nzediegwu and Chang (2020) propose to estimate daily facemask use using the Eq. 1.

Totaldailyfacemasks = populationxurbanpopulation(%)xfacemaskacceptancerate(%)
xaveragedailyfacemaskspercapita /10,000 -(1) They use Eq. 1 for estimating daily facemask use in several African states and assume that the average daily facemasks per capita is 2 and the facemask acceptance rate is 80% for several African states.
Torres and De-la-Torre (2021) propose a modi cation for this estimate and develop Eq. 2, considering economically active population. Totaldailyfacemasks = populationxurbanpopulation(%)xfacemaskacceptancerate(%) xaveragedailyfacemaskspercapitaxEconomicallyactivepoputaion(%) /100,000 -(2) These equations were used to estimate the daily facemask waste generation in Sri Lanka, assuming that the number of facemasks per capita per day is one, the facemask acceptance rate is 80% and compared with the data collected from respondents. We used the number of facemasks per capita per day as one because it is the most common assumption made in estimating daily facemask use in South Asian countries (Sangkham 2020;Haque et al. 2021).
In this study, we collected the number of family members, number of family members participating in economic activities, (thus, go out daily) and monthly facemask use of the corresponding family. Thereafter, we used the following equations to estimate the daily facemask use in Sri Lanka. In addition, our study collected data on the use of face shields, gloves and hand sanitizer bottles. All of these items were newly added to use because of the health guidelines issued due to COVID 19. We estimated daily use of those items as, Faceshields/Gloves/Sanitizerbottlesuse(Dailytotaluse) = Monthlyuseinafamily*Population/(Numberoffamilymembers*30) -(5)

Results And Discussion
There were 851 respondents for the survey. Socio-demographic information of the sample is shown in Table 1. Respondents were mainly young people, since the questionnaire was conducted online. The younger population is more likely to use social networks and participate in other online activities than the older population. However, each respondent provided details on the behavior of their own family related to the use and disposal of PPE. Respondents represented all provinces of the country.  Nzediegwu and Chang (2020), if it is assumed that one mask per capita per day and an 80% mask acceptance rate, the Sri Lankan population will use 3.19 million single-use masks per day (Table  2). If the modi cation by Torres and De-la-Torre (2021) is adopted, the value will reduce to 1.23 million masks per day (Table 2). However, our data shows that 1.35 ± 1.05 facemasks per capita per day will be used if an economically active population is taken into account. It will be reduced to 0.54 ± 0.56 per capita per day if the entire population is considered. Both calculations result in an estimate of nearly 12 million facemasks per day (Table 2). However, this includes fabric/cloth masks, hence single-use facemasks per day being used in Sri Lanka is 10 million (0.46 ± 0.46 single use facemasks per capita per day). A leading facemask manufacturer was contacted by the authors to obtain the manufacturers' estimate of market demand and he stated that expected demand of surgical and N95 masks together in Sri Lanka varies between 10-12 million per day. Besides, Selvaranjan et al. (2021) estimate that the Sri Lankan population uses 14 -70 million facemasks per week, and our estimates reach the maximum of their estimate, reaching 70 million per week.  population densities and populations that travel to work. Therefore, the estimated daily use of facemasks considering the percentage of the urban population in Sri Lanka is very low compared to the data collected by our study.
Finally, Table 3 shows that estimates made with different assumptions for the same country are drastically varied depending on the assumptions made by the studies. In Sri Lanka, we observed that repetitive use of surgical and N95 facemasks (Fig. 1), hence resulting 0.5 masks per capita per day, when entire population is considered. This might be similar to the other developing countries where income is low, hence having affordability issues. Regrettably, surgical facemasks, which were supposed to use once, are used for two days or more by nearly 20% of the sample (Fig. 1).
Torres and De-la-Torre (2021) propose a modi cation to Eq. 1 adding economically active populations as a parameter to the equation. Daily facemask use estimated by Eq. 2 in Peru is equivalent to half of the population (Torres and De-la-Torre 2021) because the percentage of the urban population is higher (nearly 70% on average in Peru) and EAP is also higher compared to Sri Lanka (56% on average in Peru and 38% on average in Sri Lanka). But, Eq. 2 reduces the estimate further for Sri Lanka. Hence, we suggest that Eq. 1 and Eq. 2 will estimate lower values of facemask usage in countries when percentage of urban population is considered to be low.
Regarding gloves, face shields and hand sanitizer bottles, 66%, 34%, 18% families do not use them respectively. Therefore, the probability of usage of gloves as a safety measure is very low. However, use of face shields and use of hand sanitizers is much higher. According to the observations made in society, senior citizens and children use face shields the most. As per the observations, except healthcare professionals, people who handle cash, super market workers etc. use gloves as a safety measure. Monthly per capita use of gloves, face shields and sanitizer bottles can be estimated as 0.34 ± 0.69, 0.43 ± 0.63 and 0.97 ± 0.83, respectively. Hence, 0.2-0.3 million gloves and face shields and 0.7 million empty hand sanitizer bottles are used in Sri Lanka within a day (Table 2).
Although many studies limited to estimate the use of facemasks, Haque et al. (2021) estimates that Bangladesh discard 1.6 million empty hand sanitizer bottles, 6.3 million surgical gloves and 40.5 million single use polythene gloves per day.
Provincial variation in PPE use is estimated (Table 2) because population density variation across provinces in uences in the difference in the number of PPE used per day. The western province generates the highest amount of PPE associated waste, because it is the most populated area in the country, although the land extent is comparatively low (Fig. 2). However, western province has the highest solid waste collection rate and bene ted with the best solid waste management methods in the country.
There are 4,063,685 school students in Sri Lanka as of 2020 (Statistics Branch of Ministry of Education of Sri Lanka 2020), and schools were fully closed for 28 weeks and partially closed for 15 weeks as of March 2021(UNESCO 2021) due to the pandemic situation. However, as of November 2021, schools were not yet fully open for the second term. Hence, the use of facemasks and other PPE by school children may not be counted under our estimation, since school children remain at home for a long period. Therefore, we can assume that the opening of schools will result in a further increase in the use of PPE and the use of hand sanitizers.

Current practices in disposal of waste associated with PPE use in household level
In almost all provinces of Sri Lanka, burning is the most common disposal method of used facemasks, followed by handing over to municipal solid waste collection (Fig. 3). Only a small percentage of households bury their waste in pits. The only exception is the Eastern province, where 55% of families hand over used facemasks to municipal solid waste collection and only 30% burn them (Fig. 3). As far as gloves, face shields, and sanitizer bottles are considered, the rate of burning is low. Yet, out of the families who use gloves, face shields and sanitizer bottles, 33% of families burn used gloves, 18% of families burn used face shields and 13% of families burn hand sanitizer bottles island wide. Very small percentages of people declare that they throw away PPE related waste without care (0.03%), while it is raised to 0.08% when it comes to plastic sanitizer bottles (Fig. 3).
In fact, different provinces in Sri Lanka have different municipal solid waste collection rates, leading different percentages of people who are left out to manage solid waste on their own. The western province has the highest municipal solid waste collection rate in Sri Lanka at 51%, and the second highest is the Eastern province at 44%. Thereafter, the northern province has 31%, followed by all the other provinces vary from 16-23%, with the north-central province having the lowest, at 15% (JICA 2016). Within a particular province, solid waste collection rates vary dependent on the type of local authority controlling the area. Accordingly, municipal solid waste collection services are provided to 50-90% of the population living in municipal council and urban council areas, while 20-75% of people receive solid waste collection facilities when they are living in divisional council areas (Unpublished data). The variation is very large because the level of service is drastically different in different provinces. The most common solid waste collection frequency in the country is once a week, while there are small numbers of families that receive the collection service twice a week or daily. dumped waste may be accessed by waste pickers for recyclable materials, stray animals may gain access to waste dumps, and contact with contaminated PPE will increase the risk, as suggested by Nzediegwu and Chang (2020). However, more serious and prolonged issues might be created due to the generation of PPE-associated waste in the long run, because most of them are single-use plastics (Sangkham 2020;Torres and De-La-Torre 2021). Most importantly, disposed face masks are a potential source of micro plastic bers that may be released into the environment (Fadare and Okoffo 2020). However, open burning of PPE also causes harmful gases and toxins to be released into the environment (Sarkodie and Owusu 2021). Therefore, emerging challenges in managing waste associated with PPE need to be addressed during the pandemic as well as after the pandemic. Thus, improvements to waste handling policies as well as clear guidelines on separation, collection, and disposal of PPE-associated waste should be added to the pandemic control guidelines.

Drawbacks identi ed and recommendations
Currently, there is a guideline issued by Central Environmental Authority of Sri Lanka to handle healthcare waste generated in households under selfquarantine and key information in the guideline are shown in Fig. 4 (CEA 2021). Even though it is in place for households under self-quarantine, there is no any guidance provided to the general public to dispose their PPE related waste otherwise. In our study, 66.5% of families stated that they separate their PPE related waste from other municipal solid waste; yet, separate collection is not taken place. Unidenti ed and symptomless, but infected people are there in the society and contaminated PPE used by them enter into municipal solid waste because of this practice.
Major drawbacks identi ed in disposal of PPE associated waste in household level in Sri Lanka is discarding PPE related waste with household waste, no use of sealed bags, not ensuring storage period of 72 hours before handing over to collection facilities and improper disposal of this waste with collected municipal solid waste. As per author's knowledge no local authority practice the collection and disposal of household healthcare waste separately under pandemic conditions.
Since expensive measures are impossible under current economic condition of the country, we suggest implementation of waste management guidelines and practices utilizing existing resources (Table 4). If PPE associated waste is collected separately issuing clear guidelines to the people, then coverage of waste collection (only for PPE associated waste) within the country can also be increased hence reducing self-management methods such as open burning.
However, above-mentioned recommendations only address the issue of spread of COVID 19 through PPE waste and unable to tackle increase of plastic waste generation due to pandemic condition. Collection of mixed solid waste with less or no precaution Separated waste can be collected as a special waste collection in a pre informed day.
Providing special bins in public places and designated collection points for people to dump PPE waste only.
This may help in increasing the coverage of waste collection service only for waste associated with PPE.
This will ensure collection crew will use PPE, because in Sri Lanka there are instances collection crew does not use protective cloths except gloves. Separate collection will increase their vigilance.
Open dumping of PPE associated waste with other waste Once separation takes place the amount of waste needed to handle with care is well-identi ed and low quantity.
Then safe burying or applying thermal treatment will be feasible.
This may reduce the risk exposure of general public and scrap collectors come into contact with this waste.
Large population is left out for self management of PPE associated waste Collect PPE waste on specially pre-allocated dates.
Providing special bins in public places and designated collection points for people to dump PPE waste only.
Increase the coverage of waste collection service for PPE associated waste only.

Handling plastic waste
Facemasks are the major component of PPE associated waste and the one liable to contaminate the most. Among the other PPE associated waste, face shields and sanitizer bottles are most probably less contaminated, but made of plastics. According to our estimates Sri Lanka generates 65 metric tonnes per day facemask waste and 88.5 metric tonnes of plastic waste due to PPE use (Table 5). It should be noted that this is in addition to the plastic and polythene waste generated under normal circumstances. Further, packaging waste quantity may have been increased because of elevated online purchase rates during pandemic situation. Since incineration is not the general practice in the country for waste disposal, it is not that easy to implement the facilities in short term. However, implementation of small-scale incinerators can be considered, at least several units for a province specially targeted to dispose healthcare waste generated in households only, because we have now spent almost two years with pandemic condition hence generating 33,300 metric tonnes of PPE associated waste per year. Although this waste amount is small compared to other South Asian countries, Sri Lanka is a small country with 65,610 km 2 housing a population of 21 million.
As a solution to excessive plastic use, the concepts of production of bio based membranes for facemasks is initialized, but the cost of production may surpass that of conventional plastics, hence limiting the actual production (Terres and De-La-Torre 2021). However, energy recovery via pyrolysis may be a viable alternative to land lling of plastic waste including medical waste (Qin et al. 2018) and affordable for developing countries.

Conclusion
The estimated daily use of facemasks, gloves, face shields and sanitizer bottles in Sri Lanka is 12 Mn, 0.22 Mn, 0.39 Mn and 0.73 Mn respectively. The estimates made in our study regarding facemask use in Sri Lanka are much higher than the estimations made by the most commonly used equations, and it is suggested that the use of percentage of the urban population as a parameter will underestimate the use of facemasks in countries with a low urban population. The percentages of families using gloves, face shields, and hand sanitizer bottles are 34%, 66%, and 82%, respectively. Regarding the disposal of used PPE, 55% of facemasks were burnt at their homes and open burning is the most common disposal method in Sri Lanka for facemasks and gloves.
However, the vast majority of people hand over sanitizer bottles and face shields to municipal solid waste collectors at the end of use. Clear guidelines are available in Sri Lanka to handle PPE associated waste generated in households subjected to self-quarantine. However, they are not applied in handling PPE associated waste generated in other households. It is recommended to handle waste associated with PPE according to guidelines, making sure discarded PPE may not impose threat of transmitting COVID 19 to society, specially, municipal waste collection crews. It is estimated that 88.5 metric tonnes per day additional plastic waste is generated in Sri Lanka a day due to COVID 19 induced PPE use and end up on land or subjected to open burning. Figure 1 Duration of using a surgical/N95 facemask  Sri Lankan guidelines issued for handling waste associated with PPE use in households subjected to self-quarantine