Crematoriums: Air Polluters Or Not?

Cremation is an increasingly popular method for the disposal of human remains due to its relatively low cost and presumed low environmental impact compared to traditional burial. However, the process of cremation involves high temperatures, requiring the use of fossil fuels and creating air pollution. Crematoria emit toxins such as carbon dioxide and mercury into the atmosphere, and the mineralized remains of the skeleton, called cremains, are often powdered and sprinkled, releasing compounds and toxins back into the environment. While there are measures to prevent or reduce pollution, such as the removal of dental fillings before cremation, cremation remains a significant source of air pollution.

Crematoria emit harmful substances such as PCDD/Fs, Hg, PM2.5, CO, NOx, SO2, and VOCs

PCDD/Fs (polychlorinated dibenzo-p-dioxins and dibenzofurans) are organic pollutants that can be formed during incomplete combustion processes or when organic compounds react with chlorine in materials such as plastics. These compounds can bioaccumulate in tissues and have been associated with negative health effects.

Hg (mercury) is a heavy metal that can arise from the volatilization of dental amalgam fillings. Exposure to Hg has been found to be higher among crematoria staff, and it has been estimated that crematoria in the UK emit 11% of all mercury released by industry and power plants.

PM2.5 refers to particulate matter with an aerodynamic diameter of 2.5 micrometres or less. These fine particles can be inhaled deep into the lungs and have been linked to negative cardiovascular and respiratory effects, as well as adverse birth outcomes.

CO (carbon monoxide), NOx (nitrogen oxides), and SO2 (sulfur dioxide) are combustion gases released during cremation. VOCs (volatile organic compounds) are also emitted and can include harmful chemicals such as benzene, which has severe effects on human health.

The relative contribution of an individual crematorium to local air pollution depends on various factors, including the number of cremations, the design of the system, and emissions control measures. While crematoria are considered small-scale installations with relatively low total emissions, they can still contribute to air pollution and pose health risks to surrounding residents.

Crematoria contribute to air pollution, particularly in residential areas

Crematoria have been found to contribute to air pollution, particularly in residential areas. The burning of human remains releases toxic emissions, including carbon dioxide, mercury, and other harmful substances. While the fumes from crematoria are filtered for particles and certain compounds, they still release toxins into the atmosphere.

The impact of crematoria emissions on air quality and human health has been a growing concern. Studies have shown that crematoria can contribute to an increase in harmful pollutants in the air, particularly in nearby residential areas. The specific pollutants released during cremation include carbon dioxide, mercury vapour, and fine particulate matter, which can be inhaled deep into the lungs and have severe effects on human health.

In Beijing, China, for example, a study found that cremators emitted harmful air pollutants such as benzene, propylene, acetone, and acrolein, which accounted for a significant percentage of the detected concentrations. Similarly, in Canada, crematoria were found to contribute approximately 5% of total PCDD/Fs, 6% of total Hg emissions, and 0.25% of PM2.5 emissions. These pollutants have been linked to adverse health effects, including an increased risk of stillbirth and brain abnormalities among babies whose mothers lived near crematoria.

To mitigate the impact of crematoria on air pollution, several measures have been proposed and implemented. Some crematoria have adopted clean energy sources, such as natural gas instead of oil, to reduce emissions. Additionally, flue gas post-treatment systems have been installed to remove acid gases, adsorb volatile organic compounds (VOCs), and capture particulate matter, thereby reducing the concentration of harmful pollutants released into the air.

Despite these efforts, the impact of crematoria on air pollution, especially in residential areas, remains a concern. Local governments in Pennsylvania, for example, have passed ordinances to regulate mercury emissions and create setback requirements from residential properties. It is important to consider the potential impact on nearby residents when planning and zoning for crematoria facilities, as well as implementing best practices to minimize the risk of exposure to harmful pollutants.

Crematoria staff are exposed to higher levels of Hg and fine particulates

Crematoria emit harmful substances such as PCDD/Fs, Hg, and fine particulate matter (PM2.5). These pollutants are released into the air during the combustion process and can have negative health effects on those exposed. While there is limited research on the health impacts of crematoria emissions specifically, studies on the individual pollutants suggest that precautionary measures should be taken to minimise risk.

Crematoria staff are at the forefront of exposure to these harmful emissions. Studies have shown that exposure to Hg (mercury) is higher among crematoria staff than in control populations. This is particularly concerning given that mercury is a neurotoxin that can bioaccumulate in tissues. The combustion of human remains, including mercury amalgam dental fillings, organohalogens, and other toxic substances, contributes to the release of mercury into the air.

In addition to mercury, crematoria staff are also at risk of inhaling fine particulate matter, especially in environments with inadequate operational and engineering controls to reduce dust exposure. The absence of standard practices for emissions controls and monitoring across some regions further exacerbates the potential health risks for crematoria workers.

The potential health consequences of exposure to fine particulate matter are significant. Inhaling these particles can increase the risks of heart disease, lung cancer, asthma, and adverse birth outcomes. It can also exacerbate other health conditions, such as diabetes. Vulnerable populations, including babies, children, pregnant women, and the elderly, are particularly at risk, according to agencies like the World Health Organization (WHO) and the United States Environmental Protection Agency (USEPA).

To protect crematoria staff from these harmful emissions, it is essential to implement best practices for design, operation, monitoring, and maintenance. This includes adopting control measures to reduce the emission of pollutants, such as clean fuel usage and combustion optimisation. Additionally, personal protective equipment (PPE) and regular health monitoring for staff can help minimise the potential health risks associated with exposure to mercury and fine particulate matter.

Cremation methods: fossil fuel-driven, natural gas, or clean energy conversion

Crematoria contribute to air pollution, particularly the release of PCDD/Fs, Hg, and PM2.5 emissions. Traditional crematoria that use wood or charcoal as fuel release emissions that can affect people's health and quality of life. Modern crematoria with double-combustion chambers have been introduced to mitigate this issue. These modern crematoria typically use fossil fuels like diesel oil or liquefied petroleum gas (LPG) as their primary fuel source, with the secondary chamber eliminating toxic gases, odors, and dust particles. However, the use of fossil fuels in cremation has led to increased cremation costs due to high global petroleum prices.

To address the environmental and economic impacts of fossil fuel usage, there is a growing interest in exploring alternative and renewable energy applications in the cremation process. One option is biomass gasification, which involves turning organic fuels into gaseous compounds, specifically producer gas or syngas, by supplying less oxygen than what is needed for complete combustion. While this process generates flammable gas that can be used for electricity or heat generation, it primarily impacts climate change and human health due to the composition of the gas produced.

Electricity offers another avenue for reducing emissions and conserving land. Electric cremation chambers could, in theory, create a cyclical effect where one cremation powers the next. This idea has gained traction in Europe, where cremation rates are high and there is a strong commitment to reducing carbon emissions. However, some crematorium operators are hesitant to adopt this approach, concerned about how it may impact the perception of their business and families' preferences.

An innovative approach to cremation energy conversion has been explored by crematoriums in Europe and the U.S., where heat waste from the cremation process is captured and converted into electricity. This concept is similar to geothermal energy, which utilizes heat from within the Earth for electricity generation. The Durham Crematorium, for example, retrofitted its burners with special turbine generators to harness heat waste.

Green alternatives to cremation: composting, alkaline hydrolysis, and green burial

Crematoria contribute to air pollution, though the impact of an individual crematorium depends on several factors, including the number of cremations, the design of the system, and the operation of the cremator. While there is limited research on the health effects of crematoria emissions, exposure to certain substances, such as Hg (mercury), is known to have negative health effects. As a result, there is a growing interest in green alternatives to traditional cremation, including composting, alkaline hydrolysis, and green burial.

Composting

Human composting is a process that places human remains into a steel vessel with water, heat, mulch, and pre-existing microbes to accelerate natural decomposition. After about 45 days, the body transforms into nutrient-rich soil and bones. This method is considered environmentally friendly as it does not directly emit significant greenhouse gases.

Alkaline Hydrolysis

Alkaline hydrolysis, also known as water cremation, is an alternative to traditional flame-based cremation. It uses water, alkaline chemicals, heat, and sometimes pressure and agitation to accelerate natural decomposition. The process is considered more environmentally friendly as it uses less fuel and has a lower carbon footprint than traditional cremation and burial. The resulting liquid effluent is sterile and can be safely released into the wastewater system or used as fertilizer.

Green Burial

A green burial, also known as a natural or eco-friendly burial, emphasizes simplicity and sustainability. In a typical green burial, the body is not cremated or prepared with chemicals but is placed in a biodegradable container and interred in a gravesite to decompose naturally. Green burials aim to minimize the environmental impact of end-of-life arrangements by using biodegradable materials and avoiding traditional embalming fluids.

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