Heavy broilers exposed to hot summer conditions experience fluctuations in surface temperatures due to heat stress, which leads to decreased performance. Maintaining a bird’s homeostasis depends on several environmental factors (temperature, relative humidity, and air velocity). It is important to understand the responses of birds to environmental factors and the amount of heat loss to the surrounding environment to create thermal comfort for the heavy broilers for improved performances and welfare. This study investigates the variation in surface temperatures of heavy broilers under high and low air velocity treatments. Daytime, age and bird location’s effect on the surface temperature variation was also examined. The experiment was carried out in the poultry engineering laboratory of North Carolina State University during summers of 2017, 2018, and 2019 as a part of a comprehensive study on the effectiveness of wind chill application to mitigate heat stress on heavy broilers. This live broiler heat stress experiment was conducted under two dynamic air velocity treatments (high and low) with three chambers per treatment and 44 birds per chamber. Surface temperatures of the birds were recorded periodically through the experimental treatment cycles (flocks, 35–61 d) with infrared thermography in the morning, noon, evening, and nighttime. The overall mean surface temperature of the broilers under two treatments was found to be 35.89 ± 2.37 °C. The variation in surface temperature happened due to air temperature, thermal index, air velocity, bird’s age, daytime, and position of birds inside the experimental chambers. The surface temperatures were found lower under high air velocity treatment and higher under low air velocity treatment. During the afternoon time, the broilers’ surface temperatures were higher than other times of the day. It was also found that the birds’ surface temperature increased with age and temperature humidity indices. Based upon the experimental data of five flocks, a simple linear regression model was developed to predict surface temperature from the birds’ age, thermal indices, and air velocity. It will help assess heavy broilers’ thermal comfort under heat stress, which is essential to provide a comfortable environment for them.

Broiler chickens exposed to heat stress adapt to various behavioral changes to regulate their comfortable body temperature, which is critical to ensure their performance and welfare. Hence, assessing various behavioral responses in birds when they are subjected to environmental changes can be essential for assessing their welfare under heat-stressed conditions. This study aimed to evaluate the effect of two air velocity (AV) treatments on heavy broilers’ behavioral changes from 43 to 54 days under summer conditions. Two AV treatments (high and low) were applied in six poultry growth chambers with three chambers per treatment and 44 COBB broilers per chamber from 28 to 61 days in the summer of 2019. Three video cameras placed inside each chamber (2.44 m × 2.44 m × 2.44 m in dimension) were used to record the behavior of different undisturbed birds, such as feeding, drinking, resting, standing, walking, panting, etc. The results indicate that the number of chickens feeding, drinking, standing, walking, sitting, wing flapping, and leg stretching changed under AV treatments. High AV increased the number of chickens feeding, standing, and walking. Moreover, a two-way interaction with age and the time of day can affect drinking and panting. This study provides insights into heavy broilers’ behavioral changes under heat-stressed conditions and AV treatments, which will help guide management practices to improve birds’ performance and welfare under commercial conditions in the future.

Fine particulate matter (i.e., PM_2.5) has gained intensive attention due to its adverse health and visibility degradation effects. As a significant fraction of atmospheric PM_2.5, secondary inorganic PM_2.5 may be formed through the gas-phase ammonia (NH₃) and particle-phase ammonium (NH₄⁺) partitioning. While partitioning of NH₃-NH₄⁺ may be simulated using a thermodynamic equilibrium model, disagreement between model predictions and measurements have been realized. In addition, the applicability of the model under different conditions has not been well studied. This research aims to investigate the applicability of a thermodynamic equilibrium model, ISORROPIA II, under different atmospheric conditions and geographic locations. Based upon the field measurements at the Southeastern Aerosol Research and Characterization (SEARCH) network, the performance of ISORROPIA II was assessed under different temperature (T), relative humidity (RH), and model setups in urban and rural locations. The impact of organic aerosol (OA) on the partitioning of NH₃-NH₄⁺ was also evaluated. Results of this research indicate that the inclusion of non-volatile cations (NVCs) in the model input is necessary to improve the model performance. Under high T (>10 °C) and low RH (10 °C) and low RH (<60%) conditions, while stable model setup might perform better under low T (<5 °C) conditions. Both model setups have consistent performance when RH is greater than 83%. Future studies using ISORROPIA II for the prediction of NH₃-NH₄⁺ partitioning should consider the inclusion of NVCs, the under/over prediction of NO₃⁻/HNO₃, the selection of stable/metastable model setups under different T-RH conditions, and spatiotemporal variations of inorganic PM_2.5 chemical compositions.

The formation of inorganic fine particulate matter (i.e., iPM_2.5) is controlled by the thermodynamic equilibrium partitioning of NH₃-NH₄⁺. To develop effective control strategies of PM_2.5, we aim to understand the impacts of changes in different precursor gases on iPM_2.5 concentrations and partitioning of NH₃-NH₄⁺. To understand partitioning of NH₃-NH₄⁺ in the southeastern U.S., responses of iPM_2.5 to precursor gases in four seasons were investigated using field measurements of iPM_2.5, precursor gases, and meteorological conditions. The ISORROPIA II model was used to examine the effects of changes in total ammonia (gas + aerosol), total sulfuric acid (aerosol), and total nitric acid (gas + aerosol) on iPM_2.5 concentrations and partitioning of NH₃-NH₄⁺. The results indicate that reduction in total H₂SO₄ is more effective than reduction in total HNO₃ and total NH₃ to reduce iPM_2.5 especially under NH₃-rich condition. The reduction in total H₂SO₄ may change partitioning of NH₃-NH₄⁺ towards gas-phase and may also lead to an increase in NO₃⁻ under NH₃-rich conditions, which does not necessarily lead to full neutralization of acidic gases (pH < 7). Thus, future reduction in iPM_2.5 may necessitate the coordinated reduction in both H₂SO₄ and HNO₃ in the southeastern U.S. It is also found that the response of iPM_2.5 to the change in total H₂SO₄ is more sensitive in summer than winter due to the dominance of SO₄²⁻ salts in iPM_2.5 and the high temperature in summer. The NH₃ emissions from Animal Feeding Operations (AFOs) at an agricultural rural site (YRK) had great impacts on partitioning of NH₃-NH₄⁺. The Multiple Linear Regression (MLR) model revealed a strong positive correlation between cation-NH₄⁺ and anions-SO₄²⁻ and NO₃⁻. This research provides an insight into iPM_2.5 formation mechanism for the advancement of PM_2.5 control and regulation in the southeastern U.S.

The broiler industry is crucial for rural economies, but it faces challenges in enhancing animal performance and well-being, particularly due to heat stress and ammonia (NH₃) in grow-out houses. This study investigates the effectiveness of air velocity (AV) treatment in reducing heat stress and NH₃ emissions while also improving litter conditions to enhance animal welfare. Conducted at the North Carolina State University’s poultry engineering laboratory, the research used six identical controlled chambers, exposing broilers to High and Low AV treatments from 28 to 61 days across four flocks during the summers of 2017 and 2018. The nitrogen mass balance (NMB) method quantified NH₃ emissions, while litter quality was assessed for moisture content, pH, total nitrogen, and total ammoniacal nitrogen. Additionally, leg health was evaluated through assessments of footpad dermatitis (FPD) and hock burns (HB) at 42 and 61 days. Results showed higher NH₃ emissions in Low AV chambers, while High AV conditions improved litter quality and resulted in greater nitrogen retention. Broilers in High AV chambers also had higher individual body weights and better leg health scores. Thus, optimizing AV effectively mitigates heat stress, controls NH₃ emissions, and enhances overall broiler performance and welfare, offering insights for sustainable industry practices.

Tools quantifying co-pollutant and public health benefits of decarbonization policies typically have coarse resolution, limiting understanding of local impacts and underestimating benefits. We present the New York Community-Scale Health and Air Pollution Policy Analysis tool, a new high resolution modeling framework to quantify the impacts of energy policies in NY on fine particulate matter (PM2.5) concentrations and public health at the census tract scale. NY CHAPPA integrates two existing reduced-form models: C-TOOLS for local-scale dispersion and COBRA for regional-scale transport to estimate total PM2.5 concentrations, physical health impacts, and their monetized value. We demonstrate the efficacy of NY-CHAPPA by applying a NY-specific policy scenario and compare results with COBRA at county scale. Under the policy scenario in 2050, NY‑CHAPPA estimates substantially greater reductions in PM2.5 concentrations (4 – 34% across NY counties compared to 2 – 8% with COBRA) and $495B in cumulative public health benefits from 2025 to 2050, which is 95% higher than COBRA. The largest reductions in PM2.5 concentrations were projected in densely populated urban areas. NY-CHAPPA enables quantification of community-scale benefits in NY’s disadvantaged communities, defined at census tract scale and not explicitly represented in other models, informing policy and investments. Statewide, projected per capita benefits in disadvantaged communities were 58% higher than in other communities.