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

Estimation of daily use of PPE

Nzediegwu and Chang (2020) propose to estimate daily facemask use using the Eq. 1.

\(x average daily facemasks per capita/\text{10,000}\) - (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 modification for this estimate and develop Eq. 2, considering economically active population.

\(x average daily facemasks per capita x Economically active poputaion \left(\%\right)/\text{100,000}\) – (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.

\(Total daily facemasks = \text{M}\text{o}\text{n}\text{t}\text{h}\text{l}\text{y} \text{f}\text{a}\text{c}\text{e}\text{m}\text{a}\text{s}\text{k} \text{u}\text{s}\text{e} \text{i}\text{n} \text{t}\text{h}\text{e} \text{f}\text{a}\text{m}\text{i}\text{l}\text{y}\text{*}\text{P}\text{o}\text{p}\text{u}\text{l}\text{a}\text{t}\text{i}\text{o}\text{n} /\left(\text{N}\text{u}\text{m}\text{b}\text{e}\text{r} \text{o}\text{f} \text{f}\text{a}\text{m}\text{i}\text{l}\text{y} \text{m}\text{e}\text{m}\text{b}\text{e}\text{r}\text{s}\text{*}30\right), \text{a}\text{s}\text{s}\text{u}\text{m}\text{i}\text{n}\text{g} \text{a} \text{m}\text{o}\text{n}\text{t}\text{h} \text{h}\text{a}\text{s} 30 \text{d}\text{a}\text{y}\text{s}\) - (3)

\(Total daily facemasks = \text{M}\text{o}\text{n}\text{t}\text{h}\text{l}\text{y} \text{f}\text{a}\text{c}\text{e} \text{m}\text{a}\text{s}\text{k} \text{u}\text{s}\text{e} \text{i}\text{n} \text{t}\text{h}\text{e} \text{f}\text{a}\text{m}\text{i}\text{l}\text{y}\text{*}\text{M}\text{o}\text{n}\text{t}\text{h}\text{l}\text{y} \text{f}\text{a}\text{c}\text{e} \text{m}\text{a}\text{s}\text{k} \text{u}\text{s}\text{e} \text{i}\text{n} \text{t}\text{h}\text{e} \text{f}\text{a}\text{m}\text{i}\text{l}\text{y}\text{*}\text{E}\text{c}\text{o}\text{n}\text{o}\text{m}\text{i}\text{c}\text{a}\text{l}\text{l}\text{y} \text{a}\text{c}\text{t}\text{i}\text{v}\text{e} \text{p}\text{o}\text{p}\text{u}\text{l}\text{a}\text{t}\text{i}\text{o}\text{n} / \left(\text{N}\text{u}\text{m}\text{b}\text{e}\text{r} \text{o}\text{f} \text{e}\text{c}\text{o}\text{n}\text{o}\text{m}\text{i}\text{c}\text{a}\text{l}\text{l}\text{y} \text{a}\text{c}\text{t}\text{i}\text{v}\text{e} \text{f}\text{a}\text{m}\text{i}\text{l}\text{y} \text{m}\text{e}\text{m}\text{b}\text{e}\text{r}\text{s} \text{*}30\right)\) - (4)

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,

\(\text{F}\text{a}\text{c}\text{e} \text{s}\text{h}\text{i}\text{e}\text{l}\text{d}\text{s}/\text{G}\text{l}\text{o}\text{v}\text{e}\text{s}/ \text{S}\text{a}\text{n}\text{i}\text{t}\text{i}\text{z}\text{e}\text{r} \text{b}\text{o}\text{t}\text{t}\text{l}\text{e}\text{s} \text{u}\text{s}\text{e} \left(\text{D}\text{a}\text{i}\text{l}\text{y} \text{t}\text{o}\text{t}\text{a}\text{l} \text{u}\text{s}\text{e}\right)= \text{M}\text{o}\text{n}\text{t}\text{h}\text{l}\text{y} \text{u}\text{s}\text{e} \text{i}\text{n} \text{a} \text{f}\text{a}\text{m}\text{i}\text{l}\text{y}\text{*}\text{P}\text{o}\text{p}\text{u}\text{l}\text{a}\text{t}\text{i}\text{o}\text{n} /\left(\text{N}\text{u}\text{m}\text{b}\text{e}\text{r} \text{o}\text{f} \text{f}\text{a}\text{m}\text{i}\text{l}\text{y} \text{m}\text{e}\text{m}\text{b}\text{e}\text{r}\text{s}\text{*}30\right)\) – (5)

Estimation of daily use of PPE

In Sri Lanka, three types of facemasks are used; surgical masks, N95 masks and cloth masks. Within the sample, 40% of families do not use cloth masks, 1.2% of families do not use surgical masks, and 9.4% of families do not use N95 masks. There were no families who do not use both surgical masks and N95 masks, i.e. families who do not use surgical masks use N95 only and vice versa. The most common calculation used in estimating the number of facemasks used per day is Eq. 1, proposed by Nzediegwu and Chang (2020). Many researchers have adopted that equation for estimating daily facemask use in many different countries (Ex. Al-Omran et al. 2021; Torres and De-la-Torre 2021; Haque et al. 2021; Zand and Heir 2021). As per 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 modification 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.

Several estimates made on the number of facemasks discarded per day for seven countries in Asia are compared in Table 3. All estimates were made using Eq. 1. Hantoko et al. (2021) does not display the values used for facemasks acceptance rate and daily facemask use per capita per day. However, calculations indicated that they have used 80% facemask acceptance rate and two masks per capita per day. Sangkham (2020) and Haque et al. 2021 have used 80% facemask acceptance rate and one mask per capita per day. Hence, Hantoko et al. (2021) estimates twice higher values than Haque et al. (2021) for India, Pakistan, Bangladesh and Indonesia.

However, Sangkham (2020) different values than other two for urban population percentage (Table 3), hence his estimates are different from others. For example, Sangkham (2020) uses Eq. 1 to estimate daily facemask use in Sri Lanka and the estimate is 17 million per day. But, Sangkham (2020) use the percentage of the urban population in Sri Lanka as 100%. Yet, it is not accurate for Sri Lanka according to available data and author’s experience. The urban population in Sri Lanka is 18.2% (Department of Census and Statistics-Sri Lanka 2012; Worldometer 2021), hence considered as a country with a low urbanized population. The definition of urban areas in Sri Lanka is areas controlled by municipal councils and urban councils (Department of Census and Statistics Sri Lanka 2010). The other non- urban areas fall on to the category of divisional councils. However, there are many divisional councils with higher 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 modification 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 influences 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 benefited 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.

Municipal solid waste collected by many local authorities in Sri Lanka is dumped in open dumps; there are only very few exceptions where sanitary landfills are used. The Greater Colombo and Colombo Metropolitan areas in western province generate the largest amount of waste and dispose the waste into Aruwakkalu sanitary landfill and Kerawalapitiya incineration plant. Therefore, in most of the occasions, disposal of used PPE, especially facemasks with other municipal solid waste, may pose a threat to public health in different ways. Handling solid waste by collection crews may expose them to the virus, openly 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 fibers 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 identified and recommendations

Currently, there is a guideline issued by Central Environmental Authority of Sri Lanka to handle healthcare waste generated in households under self-quarantine 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. Unidentified 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 identified 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.

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 km² 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 landfilling of plastic waste including medical waste (Qin et al. 2018) and affordable for developing countries.