Air Quality Impact Research Articles

The evolution of open biomass burning during summer crop harvest in the North China Plain

Open biomass burning (OBB) negatively impacts air quality by discharging abundant fine particulate matter (PM2.5, aerodynamic diameter ≤2.5 µm) and trace gases. The statistical methods and numerical simulations have been used to estimate emissions from OBB. The former is poor in producing reliable distributions and transport of emissions, while studies with the latter have focused on cases analysis over short periods. This study investigates the multi-year evaluation of OBB and its contribution to PM2.5 and black carbon (BC) based on satellite observations and numerical modeling over the North China Plain. The number of fires increased by 206% from 2008 to 2012, and decreased by 84% from 2012 to 2016, indicating that the implementation of straw burning ban policy had achieved significant positive effects. The simulation from Weather Research and Forecasting model coupled with chemistry showed that the surface concentrations of PM2.5 and BC emitted by OBB in the burning source area increased from 22 and 3.22 μg/m3, respectively, in 2008 to 45.77 and 6.47 μg/m3, respectively, in 2012, and then decreased to 1.41 and 0.22 μg/m3, respectively, in 2016. The differentiated impacts on air quality of policies across provinces are also investigated. Open crop straw burning was banned early in Shandong and Henan provinces, but they suffer from poor air quality due to open straw burning until the effective straw burning ban in Anhui and Jiangsu provinces, which suggests the need for interregional collaboration for pollution control.

Air Quality, Pollution Perception, and Residents' Health: Evidence from China.

Environmental and resident health issues associated with air pollution are an area of growing concern for both policy officials and the general public. In recent years, China has been accelerating the construction of a Beautiful China and a Healthy China, with the aim of protecting and improving the environment and ensuring public health. In this study, we aimed to explore the impact of air quality and air pollution perception on residents' health. This study used the 2017 Chinese General Social Survey data to measure self-rated health, mental health, and air pollution perception. Using matched socioeconomic indicators and air pollution data, we analyzed the relationship between subjective perception of air pollution, objective air pollution data, and residents' health. The results showed the following: (1) Air pollution perception has a significant negative impact on self-rated health and mental health. Thus, it needs more consideration to reduce environmental health risks. (2) Objective air pollution has a significant negative impact on mental health. At the same time, its effect on self-rated health was insignificant. These results provide empirical evidence supporting the Chinese government's decision to invest more in combating air pollution and ensuring the health of Chinese residents.

Secondhand electronic cigarette aerosol in vehicles impacts indoor air quality

BackgroundElectronic cigarette (ECIG) use in vehicles represents a public health concern due to the potential for exposure to high concentrations of particulate matter (PM) and other toxicants. This study examined the impact of ECIG use on air quality in vehicles. MethodsPeople who reported current ECIG use (n=60; mean age=20.5, SD=2.3) completed a brief survey and a 30-min ECIG use session in their own vehicle. Using a protocol similar to clinical laboratory studies involving tobacco use, participants took 10 directed puffs (i.e., a directed bout with one puff every 30s for 5min) followed by a 25-min ad libitum period in which participants took as many puffs as desired. PM 2.5µm in diameter or smaller (PM2.5) were measured using aerosol monitors set up to sample air from the breathing zone of the passenger seat and total puffs were recorded. The association between peak PM2.5 concentration and puff count was examined. ResultsParticipants took a median 18 total puffs during the sessions. Median PM2.5 concentrations increased from 4.78µg/m3 at baseline to 107.40µg/m3 after the directed bout. Median peak PM2.5 concentration was 464.48µg/m3 and ranged from 9.56µg/m3 to 143,503.91µg/m3 (IQR=132.72–1604.68). After removing two extreme outliers for puff count and PM2.5 concentrations, puff count was significantly correlated with peak PM2.5 concentration during the ad libitum bout (r=0.32, p=0.015). ConclusionsECIG use in vehicles impacts air quality negatively and may pose health risks to those present in vehicles when ECIG use is occurring.

Removal of volatile organic compounds by mobile air cleaners: Dynamics, limitations, and possible side effects

Air cleaners are becoming increasingly popular as a response to the increased focus on the impact of indoor air quality on human health, comfort and performance. In this study, the removal of particulate matter (PM) and volatile organic compounds (VOCs) by mobile air cleaners is investigated in an unoccupied university classroom. From time-resolved measurements by proton-transfer-reaction time of flight mass spectrometer (PTR-TOF-MS) the study reports on VOC removal and by-product formation from different air cleaning technologies. Results revealed an inconsistency between expected and experimentally obtained clean air delivery rates (CADRs). For seven out of eight air cleaners examined, the CADRs for all VOCs tested (methanol, acetaldehyde, acetone, acetic acid, isoprene, butanone, toluene, benzaldehyde and limonene) were significantly lower than the corresponding CADRs for PM. In general, single pass removal efficiencies (REs) for VOCs were found to decrease as a function of time. The VOCs demonstrated very distinctive dynamic behavior. Results indicated adsorption as the main removal mechanism of VOCs for all air cleaners for which a significant removal (RE ≥ 5%) was observed. Formation of by-products (incl. CH2O and C4H6O) was associated with technologies containing an UV lamp. Reemission of specific VOCs was observed for adsorption-based air cleaners during operation in a newly vented room. The results highlight the inadequacy of how we currently report air cleaner performance.

A new method for the quantification of ambient particulate-matter emission fluxes

Abstract. An inversion method has been developed in order to quantify the emission fluxes of certain aerosol pollution sources across a wide region in the Northern Hemisphere, mainly in Europe and western Asia. The data employed are the aerosol contribution factors deducted by positive matrix factorization (PMF) on a PM2.5 chemical composition dataset from 16 European and Asian cities for the period 2014 to 2016. The spatial resolution of the method corresponds to the geographic grid cell size of the Lagrangian particle dispersion model (Flexible Particle Dispersion Model, FLEXPART, 1∘ × 1∘) which was utilized for the air mass backward simulations. The area covered is also related to the location of the 16 cities under study. Species with an aerodynamic geometric mean diameter of 400 nm and 3.1 µm and a geometric standard deviation of 1.6 and 2.25, respectively, were used to model the secondary sulfate and dust aerosol transport. Potential source contribution function (PSCF) analysis and generalized Tikhonov regularization were applied so as to acquire potential source areas and quantify their emission fluxes. A significant source area for secondary sulfate on the east of the Caspian Sea is indicated, when data from all stations are used. The maximum emission flux in that area is as high as 10 × 10−12 kg m−2 s−1. When Vilnius, Dushanbe, and Kurchatov data were excluded, the areas with the highest emission fluxes were the western and central Balkans and southern Poland. The results display many similarities to the SO2 emission maps provided by the OMI-HTAP (Ozone Monitoring Instrument-Hemispheric Transport Air Pollution) and ECLIPSE (Evaluating the Climate and Air Quality Impacts of Short-Lived Pollutants) databases. For dust aerosol, measurements from Athens, Belgrade, Debrecen, Lisbon, Tirana, and Zagreb are utilized. The west Sahara region is indicated as the most important source area, and its contribution is quantified, with a maximum of 17.6 × 10−12 kg m−2 s−1. When we apply the emission fluxes from every geographic grid cell (1∘ × 1∘) for secondary sulfate aerosol deducted with the new method to air masses originating from Vilnius, a useful approximation to the measured values is achieved.

Quantifying the air quality impact of ship emissions in China's Bohai Bay

Bohai Bay, as a significant economic bay area in China, has experienced considerable ecological consequences during its rapid economic development. One of the major environmental challenges is the emission of air pollutants from ships, which has had a severe impact on regional air quality and the health of residents. To assess the influence of pollutants on the air quality around the Bohai Bay area, a Weather Research and Forecasting and Community Multiscale Air Quality (WRF-CMAQ) model was established using a 9 km × 9 km high-resolution ship emission gridded inventory from 2018. The WRF-CMAQ model was employed to compare two scenarios: vessel emissions and non-vessel emissions, in order to evaluate the impact of ship emissions. By analyzing the pollutant concentrations in Bohai Bay and the degree of change in pollutant concentration in six cities under these two scenarios, significant differences were observed. Furthermore, a comparison of the hourly concentration contributions of ship emissions between port cities and inland cities within the same region revealed that inland cities were less affected by ship emissions. The main contributing factors to this disparity were identified as wind direction and wind speed.

Adsorbing Volatile Organic Compounds within Bitumen Improves Colloidal Stability and Air Quality

The mass loss of bitumen due to volatilization is one of the deterioration mechanisms through which the chemical composition of bitumen deviates from its original condition, leading to change in the physical and rheological properties of bitumen. The emissions from bitumen not only accelerate its aging but also negatively impact air quality and consequently human health. Here, we characterized the molecular compositions of the volatiles emitted from bitumen in an isothermal aging process (150 °C for 24 h). We also investigated the impact of losing these compounds on the association behavior of asphaltene stacks. Based on the GC-MS results, the main mass loss of SARA (saturates, aromatics, resins, asphaltenes) fractions is attributed to the emission of lightweight nonpolar aromatic and aliphatic compounds. The most dominant volatiles are single-ring aromatics carrying short side chains, followed by saturated and unsaturated aliphatic compounds including short-chain n-alkanes, iso-alkanes, cyclic alkenes, alkenes, and dienes. Using molecular modeling in the framework of density functional theory (DFT), we showed how the reduction in aromatics and saturates can impact the colloidal stability of asphaltenes in the matrix of bitumen. Based on the DFT results, the surface adsorption of aromatics and saturates on asphaltene planes provides the steric repulsion required to maintain the asphaltene planes at a distance sufficient to inhibit their agglomeration. In addition, aromatic molecules with the least hindrance repulsion can disturb the π–π interfacial interactions between asphaltene planes, facilitating their deagglomeration. Therefore, a direct consequence of the mass loss of bitumen due to volatilization is disturbing the asphaltene distribution within the bitumen and stimulating the aggregation of asphaltenes. We also studied the merits of incorporating biochar into the bitumen surface to reduce bitumen’s mass loss. Modification of bitumen separately with each of six biochars derived from biomass feedstocks (walnut shell, peanut shell, Douglas fir, pine bark, birch, and algae) showed the efficacy of each biochar to reduce the volatiles emitted from bitumen, thereby reducing the changes in the composition of maltene with consequent colloidal stability losses. The study outcomes highlight the importance of reducing emissions from bitumen to delay its aging and minimize negative impacts on air quality and human health.

Identifying drivers affecting air quality in metropolitan areas of developing countries: evidence from Tehran metropolitan area.

Environmental issues and the significant reduction of air quality in the metropolitan areas of developing countries have become chronic challenges. While the impacts of many reasons such as the rapid trend of urbanization, lacking sustainable thinking in urban planning approaches, and urban sprawl have been explored in previous literature, the role of political economy, especially the structure based on the rentier economy, in the change of air quality as an environmental challenge in the metropolitan areas of developing countries has received little attention. To fill this gap, this study focuses on the role of the rentier economy and identifies the drivers based on it that have a tremendous impact on the air quality in Tehran metropolitan area, Iran. To this end, using the Grounded Theory (GT) foundation database and two-round Delphi survey, the opinions of 19 experts were used to identify and explain major drivers that impact air quality in Tehran. Our findings revealed that nine major drivers have an increasing impact on the air quality in the metropolitan area of Tehran. These drivers considering the dominance of the rentier economy are interpreted as the lack of powerful local governance, the rental economy, centralized structure of government, unsustainable economic development, institutional conflicts, a faulty planning system, financial unsustainability of municipalities, unfair distribution of power, and inefficient urban development policies. Among the drivers, the impacts of institutional conflicts and lack of powerful local governance on air quality are more considerable. This study highlights the role of the rentier economy as a major obstacle to resilient responses and constructive actions against chronic environmental challenges such as drastic changes in air quality in metropolitan areas of developing countries.

Evaluating Methods That Calculate Aircraft Emission Impacts on Air Quality: A Systematic Literature Review

Aircraft operations from above ground level to 3000 feet impact air quality and cause health issues, particularly for people working and living in and around airports. This paper evaluates the current emission calculation methods to identify the most accurate way to generate an emission inventory. Journal articles on aircraft influence on air quality were selected for a systematic literature review (SLR). After screening 277 articles written in English, 60 articles on emission calculation methods were included in the analysis. Based on the analysis, air quality can be more accurately assessed when considering direct emissions from an aircraft than when measuring atmospheric pollutant concentrations. While the International Civil Aviation Organization’s (ICAO) advanced approach was the most widely used from the literature reviewed, airport-specific, time-in-mode, and actual atmospheric conditions where aircraft operate offer the potential for significant improvement. The SLR demonstrates a need for more accurate emission calculation methods to assess the aircraft’s influence on air quality. The SLR guides airlines and airports to maintain an accurate emission inventory, which will set future targets to improve air quality.

Impact of poor air quality while deployed on respiratory health: a systematic review

IntroductionBritish military personnel deploy internationally to areas with high levels of ambient air pollution. Air pollution can cause acute respiratory symptoms which lead to concern about potential long-lasting health effects....

Unraveling the Relationship Between Stubble Burning and Air Quality Degradation in Punjab: A Temporal and Spatial Analysis (2019-2022)

Stubble burning in Punjab, India, poses significant environmental challenges, particularly impacting air quality. This study aims to examine the spatial and temporal patterns of stubble burning events and their potential effect on ambient air quality from 2019 to 2022. High-resolution Sentinel-2 satellite imagery was employed to delineate the spatial extent of stubble burning. Burnt areas were identified using the Normalised Burn Ratio (NBR). Air quality was evaluated based on PM2.5 and PM10 concentrations data obtained from the Punjab Pollution Control Board. The Inverse Distance Weighting (IDW) interpolation technique was used to estimate pollution values in areas lacking direct monitoring. The study revealed significant year-to-year variations in areas affected by stubble burning. The smallest burnt areas were recorded in October 2019 and 2021 (209 sq km), while the largest was in 2020 (755.38 sq km). In every year studied, the burnt area in November consistently exceeded that in October, with the largest area (10315 sq km) observed in 2021. PM2.5 and PM10 concentrations also showed annual fluctuations, with the highest recorded in 2020 and 2021. In particular, in October 2020, higher PM2.5 and PM10 levels were detected in the eastern region of Punjab. November consistently exhibited higher PM2.5 and PM10 concentrations than October for all years analysed, peaking in 2021. The spatial and temporal variations of stubble burning events and their relationship with air quality highlight the need for targeted interventions. Understanding these patterns is crucial for mitigating the adverse effects of stubble burning on air quality in Punjab, India. Future research should focus on evaluating the effectiveness of various mitigation strategies.

On the dynamics and air-quality impact of the exceptional East Asian dust outbreak in mid-March 2021

In mid-March 2021, one of the strongest dust storms of the last decade hit East Asia with adverse impacts on socio-economic activities and loss of life. The aim of this study is to assess the atmospheric dynamics involved in the temporal evolution of the Mongolian extra-tropical cyclone driving the dust event in different dust source regions in East Asia and to quantify to what extent the event was unusual for the first time. To that end, we use observation and model data from different sources. We identify that dust aerosols of the event primarily originated in the Gobi Desert. The anomalously strong dust-emitting winds were here associated with the passage of a cold front and exceeded the 99th percentile of the near-surface wind climatology for March 1992–2021 by far. Over the Loess Plateau, the dust deposition mostly exceeded the regional dust emission, indicative of the region being a net sink for dust aerosols, even during a high-impact event like in mid-March 2021. The formed dust aerosol layer of thousands of kilometers in extent led to sharp decreases in the air quality across China with record-high urban particulate matter concentrations, poor air quality, and low atmospheric visibility. Our results highlight that also the Taklamakan Desert contributed to the dust outbreak in the Western part of China. The dust emissions in the Taklamakan Desert were associated with nocturnal low-level jets that were favored by the cold air intrusion. It provides the first evidence for a link between different dust-emission mechanisms across East Asian Deserts during synoptic-scale dust outbreaks.

Extreme Smog Challenge of India Intensified by Increasing Lower Tropospheric Stability

AbstractExtreme smog in India widely impacts air quality in late autumn and winter months. While the links between emissions, air quality and health impacts are well‐recognized, the association of smog and its intensification with climatic trends in the lower troposphere, where aerosol pollution and its radiative effects manifest, are not understood well. Here we use long‐term satellite data to show a significant increase in aerosol exceedances over northern India, resulting in sustained atmospheric warming and surface cooling trends over the last two decades. We find several lines of evidence suggesting these aerosol radiative effects have induced a multidecadal (1980–2019) strengthening of lower tropospheric stability and increase in relative humidity, leading to over fivefold increase in poor visibility days. Given this crucial aerosol‐radiation‐meteorological feedback driving the smog intensification, results from this study would help inform mitigation strategies supporting stronger region‐wide measures, which are critical for solving the smog challenge in India.

The Impact of Air Quality and Meteorology on COVID-19 Cases at Kuala Lumpur and Selangor, Malaysia and Prediction Using Machine Learning

Emissions from motor vehicles and industrial sources have contributed to air pollution worldwide. The effect of chronic exposure to air pollution is associated with the severity of the COVID-19 infection. This ecological investigation explored the relationship between meteorological parameters, air pollutants, and COVID-19 cases among residents in Selangor and Kuala Lumpur between 18 March and 1 June in the years 2019 and 2020. The air pollutants considered in this study comprised particulate matter (PM2.5, PM10), sulfur dioxide (SO2), nitrogen dioxide (NO2), ozone (O3), and carbon monoxide (CO), whereas wind direction (WD), ambient temperature (AT), relative humidity (RH), solar radiation (SR), and wind speed (WS) were analyzed for meteorological information. On average, air pollutants demonstrated lower concentrations than in 2019 for both locations except PM2.5 in Kuala Lumpur. The cumulative COVID-19 cases were negatively correlated with SR and WS but positively correlated with O3, NO2, RH, PM10, and PM2.5. Overall, RH (r = 0.494; p < 0.001) and PM2.5 (r = −0.396, p < 0.001) were identified as the most significant parameters that correlated positively and negatively with the total cases of COVID-19 in Kuala Lumpur and Selangor, respectively. Boosted Trees (BT) prediction showed that the optimal combination for achieving the lowest Root Mean Squared Error (RMSE), Mean Squared Error (MSE), and Mean Absolute Error (MAE) and a higher R-squared (R2) correlation between actual and predicted COVID-19 cases was achieved with a learning rate of 0.2, a minimum leaf size of 7, and 30 learners. The model yielded an R2 value of 0.81, a RMSE of 0.44, a MSE of 0.19, and a MAE of 0.35. Using the BT predictive model, the number of COVID-19 cases in Selangor was projected with an R2 value of 0.77. This study aligns with the existing notion of connecting meteorological factors and chronic exposure to airborne pollutants with the incidence of COVID-19. Integrated governance for holistic approaches would be needed for air quality management post-COVID-19 in Malaysia.

How does coordinated regional digital economy development improve air quality? New evidence from the spatial simultaneous equation analysis

Countries around the world are increasingly turning towards developing digital economies to find better strategies for tackling the environmental pollution associated with economic growth while also pursuing high-quality economic conditions. This study aims to probe the link between coordinated regional digital economy development (RDEC) and air quality. A province-level RDEC indicator based on city-level data is developed, and air pollution is gauged by annual average PM2.5 concentrations. Furthermore, a spatial simultaneous equation model is employed to examine the causality further. The empirical results indicate that a bilateral causal relationship exists: RDEC improves air quality, and better air quality also facilitates RDEC. This relationship is influenced by spatial spillover effects. Specifically, air quality and RDEC of an area have a negative influence on the RDEC of neighboring regions, while they have a positive impact on neighboring areas' air quality. Further analysis suggests that green total factor productivity, advanced industrial structure, and regional entrepreneurship level can indirectly affect the contribution of RDEC to air quality. Additionally, the impact of air quality on RDEC may be realized through the increase in labor productivity, lower external environmental costs of regional economic development, and enhanced regional foreign economic exchange.

The future air quality impact of electric vehicle promotion and coordinated charging in the Beijing-Tianjin-Hebei region

The synergetic benefit of air quality improvements together with greenhouse gas (GHG) mitigations from fleet electrification can be maximized if the power used for electric vehicles (EVs) is from renewables. The worth-noting mismatch between renewable power generation and EV fleet charging demand requires appropriate coordination strategy. Here, we analyze the environmental benefits from increased EVs penetration in Beijing-Tianjin-Hebei (BTH) regions by integrating various scenarios of fleet electrification with coordinated charging strategies to examine the air quality improvement and GHG abatement. The study found that fleet electrification could bring substantial reduction on urban PM2.5 in BTH, especially in December by 0.8 ± 0.5 μg/m3. The coordinated charging strategy could further improve the air quality in BTH, albeit smaller than that of fleet electrification itself. PM2.5 reduction benefit from EV adoption could be significantly more pronouncing when ammonia emission reduction was considered, by more than 0.3 μg/m3 in both December and July, validating the great significance of vehicle NH3 emission control and the necessity of prioritizing the electrification of high ammonia emitting fleet. The outcome of this study helps to formulate the effective on-road transportation pollutant abatement strategies and offers technological support for policy makers to conduct more sensible sequence of future fleet electrification process.

Predicting the Equilibrium Product Formation in Oxy-fuel Combustion of Octane (C8H18) using Numerical Modeling

Preserving the environment is a major challenge for modern society, and reducing the greenhouse effect caused by combustion processes is a primary concern. It is known that nitrogen compounds (NOx) negatively impact air quality and public health. Internal combustion engines, responsible for nearly half of the atmosphere's pollutants, have prompted public policymakers to phase out gasoline and diesel-powered vehicles in the near future. Carbon capture and storage technologies, including oxy-fuel combustion, are being developed to address these environmental challenges. To predict exhaust pollutants such as NO and CO, assuming that the exhaust gases resulting from fuel and air combustion are in chemical equilibrium is a useful approximation. In the current case study, a numerical investigation on the impact of modifying the oxygen content of the reaction mixture from 21% to 100% on the equilibrium composition of C8H18 air-enriched combustion was conducted. Specifically, the equilibrium-constant approach routines were tailored for 10 species reported in the literature to the conditions of oxy-fuel combustion. Additionally, a comprehensive analysis was performed by varying the temperature and equivalence ratio alongside the oxygen level. The results emphasize the intricate interplay between various factors in oxy-combustion and provide valuable insight into the equilibrium product formation in oxy-fuel combustion. Notably, the non-uniform reduction of N2 as a function of O2 is highlighted, with an overall reduction rate of 0.93 observed across the range of O2 percentages from 21% to 99%.

Impact of Air Quality on Millimeter Wave Transmission Performance

In this paper, we use millimeter wave radar to conduct outdoor experiments under different air quality conditions and analyze the degree of millimeter wave transmission attenuation. The radar we use operates at 94 GHz with a bandwidth of 1 GHz, a distance resolution of 15 cm, and a maximum detection distance of about 150 meters. We mainly use PM2.5 and PM10 indices as air quality criteria and find that the reflected signal strength of millimeter wave from 90m to 150m decreases by 0.38dB when the air quality rises from 136 to 250, indicating that the weaker the air quality, the weaker the millimeter wave signal strength. This provides an experimental basis for the field of millimeter wave communication.

The impact of poor housing and indoor air quality on respiratory health in children.

The reader should understand how housing quality and indoor air quality affect respiratory health in children.The reader should understand which children are at most risk of living in poor-quality housing.The reader should understand what policy recommendations have been made and what actions need to be undertaken to improve housing quality and respiratory health in children and young people.

Temporal Variations of Air Quality in Cage-Free Experimental Pullet Houses

The welfare of laying hens in conventional caged houses has become an increased public concern, leading primary food chains, restaurants, and grocers in the United States to pledge to source only cage-free (CF) eggs by 2025 or 2030. Cage-free housing systems have been considered as a more humane alternative; however, they still come with certain challenges. One of the primary challenges with CF housing is the poor indoor air quality due to the high levels of ammonia (NH3) and particulate matter (PM). Despite the importance of air quality in animal welfare, most studies have focused on the egg-laying stage, thereby leaving a significant knowledge gap in the pullet phase. Addressing this gap is essential to ensure the well-being of laying hens in CF housing and to help producers and researchers identify effective strategies to mitigate the impact of poor indoor air quality on the bird’s health and welfare. Therefore, the objective of this study was to (a) examine the effect of the pullets’ age on NH3 and PM levels, and (b) find the effect of housing, litter moisture content (LMC), and relative humidity (RH) on air pollutant concentrations. The results show that the PM levels of PM2.5, PM10, and total suspended particles (TSP) increased significantly with the growth of birds from 1 to 16 weeks of age (WOA) (p < 0.01). For instance, PM2.5, PM10, and TSP levels were measured at 0.023 ± 0.003, 0.031 ± 0.004, and 0.058 ± 0.013 mg m−3 in the first week, and these levels increased to 1.44 ± 0.58, 2.723 ± 1.094, and 6.39 ± 2.96 mg m−3, respectively, by 16 WOA. In addition, PM levels measured near the perch were found to be three times higher than other locations inside the rooms (e.g., between the feeder and drinker or near the exhaust fan) (p < 0.01), as perching is one of the primary reasons for dust generation. Furthermore, a significant interaction between the age of the pullets and PM levels was found (p < 0.01), as the litter quality and the behaviors of birds were changing over time. For NH3 levels, average daily concentrations were lower than 1 ppm at 16 WOA for all rooms due to dry litter conditions (i.e., 9–10% LMC). Additionally, RH has been shown to have a significant effect on air pollutant concentration. Overall, the results indicate that the bird’s age significantly affects PM generation and PM variation within the rooms. The variation of PM was directly affected by RH inside the house. Therefore, this research will provide valuable information for both researchers and producers to control air pollutant emissions from the pullet stage in CF housing to ultimately improve the health and welfare of hens.