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Assessing the PM2.5 impact of biomass combustion in megacity Dhaka, Bangladesh - PubMed (nih.gov)

This article is about crop burning in Dhaka, Bangladesh and attempts to figure out if there is more or less harmful PM2.5 particulate air pollution caused by either fossil fuels or biomass, and during which season is one or the other higher in the air pollution it produces. During monsoon season, fossil fuels lead in the most PM2.5 releases at 44.3%. When it is not monsoon season and is the winter season, the percentages are way higher for PM2.5 air particulate releases at 41.4% for the remainder of the year. Across the globe, there are now people stepping up to uncover the true and real environmental and health impacts this harmful particulate byproduct causes in different parts of the world and with differring weather conditions than what we see in North Carolina. 

https://www.researchgate.net/publication/351209404_PM25_Emissions_from_…;

This study is set in South/Southeast Asia and uncovering that, when trying to count the percentages of PM2.5 put off during biomass, the true amount of emissions were being gravely undercalculated. Specifically rice straw burning becuase the amount burned varied so much because of different harvest and burning practices that it just wasn't taken into consideration. What this study does is go bottom up using these strategies: "subnational spatial database of rice-harvested area, region-specific fuel-loading factors, region, and burning-practice-specific emission and combustion factors, including literature-derived estimates of straw and stubble burned"(Lasko et al. 2021, 1). 

The most common air pollutants are called criteria pollutants and are regulated by the Clean Air Act and the EPA. These pollutants are: particles, ozone, nitrogen oxides, sulfer dioxide, carbon monoxide, and lead. The EPA have sections under the CAA that help regulate factories and air pollution in the environment. For example section 108 requires the EPA to identify the pollutants that are criteria pollutants, listed above, and determine if where they are coming from and if they "endander public health or welfare". Under section 109 the EPA had to set standards across the board for air pulltion in regard to human health and to the environemtn sperately (Christopher D. Ahlers 2016, 51-52).  There are many more sections that go into detail about what the CAA can do and what the EPA members are required to do as well. 

Most recent news (As of September 2022) focuses on the EPAs naming of 23 EtO sterilization plants as high risk. This announcement enables local leadership, environmental organizations and legal partners to assess human health risks while focusing on reducing EtO emissions, as outlined by the EPA. Most recent news (As of September 2022) focuses on the EPAs naming of 23 EtO sterilization plants as high risk. This announcement has enabled local leadership, environmental organizations and legal partners to assess human health risks while focusing on reducing EtO emissions, as outlined by the EPA. This release by the EPA has prompted activism in the communities affected by EtO sterilization facilities. As noted by EarthJustice on the news, “Raul Garcia, legislative director for Healthy Communities at Earthjustice: ‘This is an important and welcome step to increasing transparency on the toxic air pollution and health threats that sterilizer facilities pose to the health of millions of Americans. Now that EPA has new information on precisely where the worst health threats are, the agency must use its full authority to ensure public health so no one gets cancer from this pollution and require fenceline monitoring at these facilities. Now, EPA must issue a strong new rule that phases out the use of ethylene oxide at commercial sterilizers. No one should get cancer from facilities that are used to sterilize equipment in the treatment of cancer.’ “. In addition, one major article edited and published by ProPublica sparked both outrage but in addition, change. The article The Most Detailed Map of Cancer-Causing Industrial Air Pollution in the U.S. details 

Activism has prompted more indepth research, increased acquisition and availability of EtO industry data, and increased focus on EtO as a carcinogen and toxin. This hazard was recognized fully by the EPA between 2016-2018 which led to increased assessment and acknowledgement of EtO as a toxin.

The main concern with EtO exposure includes inhalation. Laws that regulate air emissions have invariably affected and regulated this hazard. But specifically, below is a rough outline of  laws that directly impacted the air emissions of facilities processing EtO: 

• Clean Air Act Section 112, Hazardous Air Pollutants. The CAA regulates Ethylene Oxide under section 112 of the CAA. The CAA labels EtO as a hazardous air pollutant. Under the CAA, EtO emissions can be regulated in conjunction with promoting the best emission controls.

• Regulations on Sterilization Facilities (From Federal Register : National Emission Standards for Hazardous Air Pollutants: Ethylene Oxide Commercial Sterilization and Fumigation Operations) 

Note, fugitive emissions have not been standardized by the EPA, including back vents, emergency ventilation etc.

Mainly stark contrast can be found between the EPA and various state and chemical manufacturing companies in terms of data divergence. The main concern surrounding EtO is the elevated cancer risk that occurs with long exposure both direct and indirect. The ways in which the EPA and other companies and agencies assess risk have been different in terms of unit quantity. The EPA utilized in 2016 the Integrated Risk Information System to model cancer risk. According to the American Chemical Council the, “ACC believes the value is significantly flawed.” Also, the Texas Commision on Environmental Quality has stated, “ ‘the US EPA unit risk factor (URF) for ethylene oxide is not scientifically justified.’ ”. This has led the TCEQ to raise its exposure limit from 1 ppb to 2.4 ppb.

• Results of the Risk Assessment of Ethylene Oxide Emitting Facilities in Texas and Louisiana

Provides a list of 8 high risk EtO facilities both in LA and TX. Provides a breakdown of race in terms of proximity to facility and risk level. *One point to mention, is that data from the 2018 National Emissions Inventory (NEI), which was used, is provided to the EPA by the LDEQ and TCEQ.*

• Ethylene Oxide Risk Map - Air Alliance Houston

Mapped by the Environmental Advocacy group Air Alliance Houston are EtO facilities across America. The top 25 EtO emitting facilities are labeled and census tracts with a cancer risk greater than 100 in 1 million are also highlighted.

The major organization involved in assessment of EtO is the EPA. The EPA and its branch leaders have spearheaded the response guidelines, have outlined cancer risks, and have conducted research in partnership with other national partners such as the NIH, federal departments of health, and state departments of health.

In the period between 1982 to 1984 multiple studies on lab rats concluded that inhalation concentrations of ethylene oxide could be correlated to cancer development. An analysis of the results found that increased exposure showed higher incidences of tumor development in both male and female lab rats. According to the EPA EtO is carcinogenic and, “Scientific evidence in humans indicates that exposure to EtO for many years increases the risk of cancers of the white blood cells, including non-Hodgkin lymphoma, myeloma, and lymphocytic leukemia. Studies also show that long-term exposure to EtO increases the risk of breast cancer in women.”