Emerging Contaminants

This chapter discusses water pollution control and abatement strategies in relation to emerging contaminants. The pollution prevention measures described in the chapter can broadly be categorized into four main areas that are highly interdependent: behavioral changes, new technical solutions to aid remediation of the environment, further research and data availability, and legislation or policy reforms. These main areas have been expanded in detail under 13 subtitles that are not only interdependent but also practical and achievable. The chapter demonstrates that if the proposed measures are collectively taken into consideration, then most of the United Nations Sustainable Development goals, especially the goals relating to water quality, would become a reality. The benefits of pollution control and abatement are widespread and far-reaching and can better the quality of life on the planet.

2 Measuring the Impact of Heat Stress Abatement Strategies on Fecal Microbiome in Finishing Steers During the Summer Months in the Southeast United States

This study evaluated the effect of heat stress abatement strategies on the faecal microbiome of finishing beef steers in the Southeastern United States. The study was designed as a completely randomized block using 32 steers (BW 453k 4 kg) stratified by weight and randomly assigned to one of four treatment groups: covered with fans (CWF), covered no fans (CNF), outside with shade (SHADE), and outside without shade (OUT). All steers were housed outside from June to July and were brought up on a common feedlot ration. After-which steers were placed into treatments on d -10 and covered steers were given 10 days to acclimate Calan-gate system. During the acclimation phase, both covered and outside steers were brought up at a similar rate. Steers were weighed and faecal samples were collected on d 0, 50, and 85. Microbial DNA was extracted from the samples using a combination of mechanical and enzymatic processes, and the DNA sequences were analyzed using QIIME v2.0. There was a treatment x day interaction for Actinobacteriota, Bacteroidota, and Patescibacteria phyla. Additionally, there was a day effect for all three phyla (P < 0.001), but there was only a treatment effect (P < 0.001) for Patescibacteria. There was not an interaction for Fibrobacterota, Firmicutes, or Proteobacteria (P > 0.226), but there was a day effect (P < 0.019) for all three phyla. There was a treatment effect (P = 0.036) for Fibrobacterota, however there was not a treatment effect for Firmicutes and Proteobacteria (P > 0.394). Moreover, there was no interaction, treatment, or day effect (P > 0.39) for the Firmicutes to Bacteroidota ratio. These results suggest that stress abatement strategies may influence the fecal microbiome over time, and they might help better understand how stress affects the microbiome and nutrient digestibility in the lower gut.

In situ ozone production is highly sensitive to volatile organic compounds in Delhi, India

The Indian megacity of Delhi suffers from some of the poorest air quality in the world. While ambient NO2 and particulate matter (PM) concentrations have received considerable attention in the city, high ground-level ozone (O3) concentrations are an often overlooked component of pollution. O3 can lead to significant ecosystem damage and agricultural crop losses, and adversely affect human health. During October 2018, concentrations of speciated non-methane hydrocarbon volatile organic compounds (C2–C13), oxygenated volatile organic compounds (o-VOCs), NO, NO2, HONO, CO, SO2, O3, and photolysis rates, were continuously measured at an urban site in Old Delhi. These observations were used to constrain a detailed chemical box model utilising the Master Chemical Mechanism v3.3.1. VOCs and NOx (NO + NO2) were varied in the model to test their impact on local O3 production rates, P(O3), which revealed a VOC-limited chemical regime. When only NOx concentrations were reduced, a significant increase in P(O3) was observed; thus, VOC co-reduction approaches must also be considered in pollution abatement strategies. Of the VOCs examined in this work, mean morning P(O3) rates were most sensitive to monoaromatic compounds, followed by monoterpenes and alkenes, where halving their concentrations in the model led to a 15.6 %, 13.1 %, and 12.9 % reduction in P(O3), respectively. P(O3) was not sensitive to direct changes in aerosol surface area but was very sensitive to changes in photolysis rates, which may be influenced by future changes in PM concentrations. VOC and NOx concentrations were divided into emission source sectors, as described by the Emissions Database for Global Atmospheric Research (EDGAR) v5.0 Global Air Pollutant Emissions and EDGAR v4.3.2_VOC_spec inventories, allowing for the impact of individual emission sources on P(O3) to be investigated. Reducing road transport emissions only, a common strategy in air pollution abatement strategies worldwide, was found to increase P(O3), even when the source was removed in its entirety. Effective reduction in P(O3) was achieved by reducing road transport along with emissions from combustion for manufacturing and process emissions. Modelled P(O3) reduced by ∼ 20 ppb h−1 when these combined sources were halved. This study highlights the importance of reducing VOCs in parallel with NOx and PM in future pollution abatement strategies in Delhi.

Near-Source Risk Functions for Particulate Matter Are Critical When Assessing the Health Benefits of Local Abatement Strategies

When mortality or other health outcomes attributable to fine particulate matter (PM2.5) are estimated, the same exposure–response function (ERF) is usually assumed regardless of the source and composition of the particles, and independently of the spatial resolution applied in the exposure model. While several recent publications indicate that ERFs based on exposure models resolving within-city gradients are steeper per concentration unit (μgm−3), the ERF for PM2.5 recommended by the World Health Organization does not reflect this observation and is heavily influenced by studies based on between-city exposure estimates. We evaluated the potential health benefits of three air pollution abatement strategies: electrification of light vehicles, reduced use of studded tires, and introduction of congestion charges in Stockholm and Gothenburg, using different ERFs. We demonstrated that using a single ERF for PM2.5 likely results in an underestimation of the effect of local measures and may be misleading when evaluating abatement strategies. We also suggest applying ERFs that distinguish between near-source and regional contributions of exposure to PM2.5. If separate ERFs are applied for near-source and regional PM2.5, congestion charges as well as a reduction of studded tire use are estimated to be associated with a significant reduction in the mortality burden in both Gothenburg and Stockholm. In some scenarios the number of premature deaths is more than 10 times higher using separate ERFs in comparison to using a single ERF irrespective of sources as recommended by the WHO. For electrification, the net change in attributable deaths is small or within the uncertainty range depending on the choice of ERF.

In situ Ozone Production is highly sensitive to Volatile Organic Compounds in the Indian Megacity of Delhi

The Indian megacity of Delhi suffers from some of the poorest air quality in the world. While ambient NO2 and particulate matter (PM) concentrations have received considerable attention in the city, high ground level ozone (O3) concentrations are an often overlooked component of pollution. O3 can lead to significant ecosystem damage, agricultural crop losses, and adversely affect human health. During October 2018, concentrations of speciated non-methane hydrocarbons volatile organic compounds (C2 – C13), oxygenated volatile organic compounds (o-VOCs), NO, NO2, HONO, CO, SO2, O3, and photolysis rates, were continuously measured at an urban site in Old Delhi. These observations were used to constrain a detailed chemical box model utilising the Master Chemical Mechanism v3.3.1. VOCs and NOx (NO + NO2) were varied in the model to test their impact on local O3 production rates, P(O3), which revealed a VOC-limited chemical regime. When only NOx concentrations were reduced, a significant increase in P(O3) was observed, thus VOC co-reduction approaches must also be considered in pollution abatement strategies. Of the VOCs examined in this work, mean morning P(O3) rates were most sensitive to monoaromatic compounds, followed by monoterpenes and alkenes, where halving their concentrations in the model led to a 15.6 %, 13.1 % and 12.9 % reduction in P(O3), respectively. P(O3) was not sensitive to direct changes in aerosol surface area but was very sensitive to changes in photolysis rates, which may be influenced by future changes in PM concentrations. VOC and NOx concentrations were divided into emission source sectors, as described by the EDGAR v5.0 Global Air Pollutant Emissions and EDGAR v4.3.2_VOC_spec inventories, allowing for the impact of individual emission sources on P(O3) to be investigated. Reducing road transport emissions only, a common strategy in air pollution abatement strategies worldwide, was found to increase P(O3), even when the source was removed in its entirety. Effective reduction in P(O3) was achieved by reducing road transport along with emissions from combustion for manufacturing and process emissions. Modelled P(O3) reduced by ~20 ppb h−1 when these combined sources were halved. This study highlights the importance of reducing VOCs in parallel with NOx and PM in future pollution abatement strategies in Delhi.