Accurate determination of the atmospheric particulate matter mass concentration and chemical composition is helpful in exploring the causes and sources of atmospheric enthalpy pollution and in ...evaluating the rationality of environmental air quality control strategies. Based on the sampling and chemical composition data of PM
2.5
in different key regions of China in the CARE-China observation network, this research analyzes the environmental air quality data released by the China National Environmental Monitoring Centre during the studied period to determine the changes in the particulate matter mass concentration in key regions and the evolution of the corresponding chemical compositions during the implementation of the
Action Plan for Prevention and Control of Air Pollution
from 2013–2017. The results show the following. (1) The particulate matter mass concentration in China showed a significant downward trend; however, the PM
2.5
annual mass concentration in 64% of cities exceeds the New Chinese Ambient Air Quality Standard (CAAQS) Grade II (GB3095-2012). The region to the east of the Taihang Mountains, the Fenhe and Weihe River Plain and the Urumqi-Changji regions in Xinjiang, all have PM
2.5
concentration loading that is still high, and heavy haze pollution occurred frequently in the autumn and winter. (2) During the heavy pollution in the autumn and winter, the concentrations of sulfate and organic components decreased significantly. The mean
S
O
4
2
−
concentration in PM
2.5
decreased by 76%, 12%, 81% and 38% in Beijing-Tianjin-Hebei (BTH), the Pearl River Delta (PRD), the Sichuan-Chongqing region (SC) and the Fenhe and Weihe River Plain, respectively. The mean organic matter (OM) concentration decreased by 70%, 44%, 48% and 31%, respectively, and the mean concentration of
N
H
4
+
decreased by 68%, 1.6%, 38% and 25%, respectively. The mean elemental carbon (EC) concentration decreased by 84% and 20% in BTH and SC, respectively, and it increased by 61% and 11% in the PRD and Fenhe and Weihe River Plain, respectively. The mean concentration of mineral and unresolved chemical components (MI) dropped by 70%, 24% and 13% in BTH, the PRD and the Fenhe and Weihe River Plain, respectively. The change in the PM
2.5
chemical composition is consistent with the decrease of the PM
2.5
mass concentration. (3) In 2015, the mean OM concentration contributions to fine particles and coarse particles were 13–46% and 46–57%, respectively, and the mean MI concentration contributions to fine particles and coarse and particles were 31–60% and 39–73%, respectively; these values are lower than the 2013 values from the key regions, which is the most important factor behind the decrease of the particulate matter mass concentration. From 2013 to 2015, among the chemical components of different particle size fractions, the peak value of the coarse particle size fraction decreased significantly, and the fine particle size fractions of
S
O
4
2
−
,
N
O
4
−
,
a
n
d
N
H
4
+
decreased with the decrease of the particulate matter mass concentration in different particle size fractions. The fine-particle size peaks of
S
O
4
2
−
,
N
O
4
−
,
a
n
d
N
H
4
+
shifted from 0.65–1.1 μm to the finer size range of 0.43–0.65 μm during the same time frame.
This study involved a seasonal exposure assessment in a hospital environment using several air quality indicators including carbon monoxide (CO), carbon dioxide (CO2), particulate matter (PM10 and ...PM2.5), and total volatile organic compounds (TVOCs). We examined the distribution of and variation in the indoor and outdoor pollutant concentrations in 12 working areas across three hospitals, with an emphasis on capturing seasonal variations. We assessed correlations between measured indoor and outdoor levels to quantify the importance of indoor sources on air quality relative to outdoor sources. Our results indicated that while indoor and outdoor CO levels were below air quality standards/guidelines, measured PM2.5 and PM10 concentrations at several locations exceeded the standards 2- to 3.5-fold. We generally recorded higher indoor PM levels during the warm season, particularly during regional desert storm events. The ingress of particles from the outdoor to indoor environment was evident with high correlations between indoor and outdoor PM2.5 (r between 0.83 and 0.92) and PM10 (r between 0.74 and 0.86) levels, particularly during the warm season. Indoor to outdoor (I/O) ratios of PM2.5 and PM10 were mostly < 1. In contrast, indoor levels of CO2 and TVOCs exceeded outdoor concentrations during both the warm and cold seasons with I/O ratios >1 across all sampling locations. Our paper concludes with implications of high PM exposure and a suggested management framework for limiting such exposure in hospitals.
•Monitoring seasonal variation of indoor and outdoor air quality indicators in hospitals.•PM2.5 and PM10 exhibited levels exceeding health standards by 2–3.5 folds.•Indoor/outdoor ratios of PM2.5, PM10, and TVOC increased during the warm season.•High correlations between indoor and outdoor PM2.5 (r = 0.83 to 0.92) and PM10 (r = 0.74 to 0.86).•Indoor CO2 and TVOC levels exceeded those recorded outdoor with I/O ratios >1.
Stereoscopic Monitoring Liu, Cheng; Gao, Meng; Hu, Qihou ...
Bulletin of the American Meteorological Society,
04/2021, Volume:
102, Issue:
4
Journal Article
Peer reviewed
Open access
Monitoring and modeling/predicting air pollution are crucial to understanding the links between emissions and air pollution levels, to supporting air quality management, and to reducing human ...exposure. Yet, current monitoring networks and modeling capabilities are unfortunately inadequate to understand the physical and chemical processes above ground and to support attribution of sources. We highlight the need for the development of an international stereoscopic monitoring strategy that can depict three-dimensional (3D) distribution of atmospheric composition to reduce the uncertainties and to advance diagnostic understanding and prediction of air pollution. There are three reasons for the implementation of stereoscopic monitoring: 1) current observation networks provide only partial view of air pollution, and this can lead to misleading air quality management actions; 2) satellite retrievals of air pollutants are widely used in air pollution studies, but too often users do not acknowledge that they have large uncertainties, which can be reduced with measurements of vertical profiles; and 3) air quality modeling and forecasting require 3D observational constraints. We call on researchers and policymakers to establish stereoscopic monitoring networks and share monitoring data to better characterize the formation of air pollution, optimize air quality management, and protect human health. Future directions for advancing monitoring and modeling/predicting air pollution are also discussed.
This review provides a community's perspective on air quality
research focusing mainly on developments over the past decade. The article
provides perspectives on current and future challenges as well ...as research
needs for selected key topics. While this paper is not an exhaustive review
of all research areas in the field of air quality, we have selected key
topics that we feel are important from air quality research and policy
perspectives. After providing a short historical overview, this review
focuses on improvements in characterizing sources and emissions of air
pollution, new air quality observations and instrumentation, advances in air
quality prediction and forecasting, understanding interactions of air
quality with meteorology and climate, exposure and health assessment, and
air quality management and policy. In conducting the review, specific
objectives were (i) to address current developments that push the boundaries
of air quality research forward, (ii) to highlight the emerging prominent
gaps of knowledge in air quality research, and (iii) to make recommendations to guide the direction for future research within the wider
community. This review also identifies areas of particular importance for
air quality policy. The original concept of this review was borne at the
International Conference on Air Quality 2020 (held online due to the COVID
19 restrictions during 18–26 May 2020), but the article incorporates a wider
landscape of research literature within the field of air quality science. On
air pollution emissions the review highlights, in particular, the need to
reduce uncertainties in emissions from diffuse sources, particulate matter
chemical components, shipping emissions, and the importance of considering
both indoor and outdoor sources. There is a growing need to have integrated
air pollution and related observations from both ground-based and remote
sensing instruments, including in particular those on satellites. The research
should also capitalize on the growing area of low-cost sensors, while
ensuring a quality of the measurements which are regulated by guidelines.
Connecting various physical scales in air quality modelling is still a
continual issue, with cities being affected by air pollution gradients at
local scales and by long-range transport. At the same time, one should allow
for the impacts from climate change on a longer timescale. Earth system
modelling offers considerable potential by providing a consistent framework
for treating scales and processes, especially where there are significant
feedbacks, such as those related to aerosols, chemistry, and meteorology.
Assessment of exposure to air pollution should consider the impacts of
both indoor and outdoor emissions, as well as application of more sophisticated,
dynamic modelling approaches to predict concentrations of air pollutants in
both environments. With particulate matter being one of the most important
pollutants for health, research is indicating the urgent need to understand,
in particular, the role of particle number and chemical components in terms
of health impact, which in turn requires improved emission inventories and
models for predicting high-resolution distributions of these metrics over
cities. The review also examines how air pollution management needs to
adapt to the above-mentioned new challenges and briefly considers the
implications from the COVID-19 pandemic for air quality. Finally, we provide recommendations for air quality research and support for policy.
Government has implemented various scattered and un-quantified control actions in Delhi city to reduce the air pollution levels; however, it still exceeds the National Ambient Air Quality Standards ...(NAAQS). The present study has been designed to assess the air quality status, identify Air Quality Control Region (AQCR), and evaluate control strategies in the city. Out of eight selected locations, ambient PM
10
, PM
2.5
, and NO
2
concentrations were found exceeding the daily as well as annual standards at selected AQCR with peak levels during post-monsoon than winter and summer. Anand Vihar was found to be most polluted and thus, selected as an AQCR. AERMOD performed satisfactorily in predicting pollutant concentration during winter and summer having an index of agreement in the range 0.54–0.80. PM
10
and PM
2.5
can be reduced substantially by increasing frequency of efficient mechanized cleaning of roads and sprinkling of water on the roads. Progressive decrease in NO
2
concentrations can be achieved by restricting entry of truck in the study area through alternate path. The cumulative impact of all selected control strategies indicates a substantial decrease in air pollution within AQCR. The study also suggests a policy framework to manage the urban air quality through local scale air quality guidelines.
Recent technological advancements have enabled the development and deployment of low-cost consumer grade monitors for ubiquitous and time-resolved indoor air quality monitoring. With their reliable ...performance, this technology could be instrumental in enhancing automatic controls and human decision making. We conducted a comprehensive performance evaluation of eight consumer grade multi-parameter monitors and eight single-parameter sensors in detecting particulate matter, carbon dioxide, total volatile organic compounds, dry-bulb air temperature, and relative humidity. In the controlled chamber, we generated eight air pollution sources, each at two thermodynamic conditions — cool and dry (20 ± 1 °C, 30 ± 5%), and warm and humid (26 ± 1 °C, 70 ± 5%). The majority of tested devices under-reported reference particle measurements by up to 50%, provided acceptable responses for carbon dioxide within 15% and diverging results with poor quantitative agreement for total volatile organic compounds. Despite the reported disparities in quantitative agreements, most of the low-cost devices could detect source events and were strongly correlated with the reference data, suggesting that these units could be suitable for measurement-based indoor air quality management. Most of the tested devices have also proven to competently measure air temperature (within+/-0.6 °C) and relative humidity (within+/-5% RH) and maintained a stable measurement accuracy over the two thermodynamic conditions.
•We evaluated 8 low-cost environmental monitors and 8 single sensors in 2 distinct seasons.•Most of the tested units can be used for measurement-based IAQ and comfort management.•Awair 2nd Edition scored highest overall accuracy in measuring multiple environmental parameters among the low-cost units.•Air pollution source type affects monitor accuracy while seasonal impact is not obvious.•Price of the low-cost monitors does not scale with their performance.
China is challenged with the simultaneous goals of improving air quality and mitigating climate change. The “Beautiful China” strategy, launched by the Chinese government in 2020, requires that all ...cities in China attain 35 μg/m³ or below for annual mean concentration of PM2.5 (particulate matter with aerodynamic diameter less than 2.5 μm) by 2035. Meanwhile, China adopts a portfolio of low-carbon policies to meet its Nationally Determined Contribution (NDC) pledged in the Paris Agreement. Previous studies demonstrated the cobenefits to air pollution reduction from implementing low-carbon energy policies. Pathways for China to achieve dual targets of both air quality and CO₂ mitigation, however, have not been comprehensively explored. Here, we couple an integrated assessment model and an air quality model to evaluate air quality in China through 2035 under the NDC scenario and an alternative scenario (Co-Benefit Energy CBE) with enhanced low-carbon policies. Results indicate that some Chinese cities cannot meet the PM2.5 target under the NDC scenario by 2035, even with the strictest end-of-pipe controls. Achieving the air quality target would require further reduction in emissions of multiple air pollutants by 6 to 32%, driving additional 22% reduction in CO₂ emissions relative to the NDC scenario. Results show that the incremental health benefit from improved air quality of CBE exceeds 8 times the additional costs of CO₂ mitigation, attributed particularly to the cost-effective reduction in household PM2.5 exposure. The additional low-carbon energy polices required for China’s air quality targets would lay an important foundation for its deep decarbonization aligned with the 2 °C global temperature target.
Mechanisms for high offshore ozone (O3) events in the Houston area have not been systematically examined due to limited O3 measurements over water. In this study, we used the datasets collected by ...three boats deployed in Galveston Bay and the Gulf of Mexico during the Tracking Aerosol Convection Interactions ExpeRiment – Air Quality (TRACER-AQ) field campaign period (September 2021), in combination with the Weather Research and Forecasting (WRF) coupled Comprehensive Air quality Model with Extensions (CAMx) modeling system (WRF–CAMx), to investigate the reasons for high offshore O3. The model can capture the spatiotemporal variability in the daytime (10:00–18:00 central daylight time, CDT) O3 for the three boats (R > 0.7) but tends to overestimate O3 by ∼ 10 ppb on clean days and underestimate O3 by ∼ 3 ppb during high-O3 events. The process analysis tool in CAMx identifies O3 chemistry as the major process leading to high-O3 concentrations. The region-wide increase in the long-lived volatile organic compounds (VOCs) through advection transits O3 formation to be more sensitive to NOx, leading to more O3 production under a NOx-limited regime. In addition, the VOC-limited O3 formation is also boosted along western Galveston Bay and the Gulf Coast under high-NOx conditions brought by the northeasterly winds from the Houston Ship Channel. Two case studies illustrate that high offshore O3 events can develop under both large- and mesoscale circulations, indicating both the regional and local emissions need to be stringently controlled. Wind conditions are demonstrated to be important meteorological factors in such events, so they must be well represented in photochemical models to forecast air quality over the urban coastal regions accurately.
The AIRUSE-LIFE+ project aims at characterizing similarities and heterogeneities in particulate matter (PM) sources and contributions in urban areas from southern Europe. Once the main PMx sources ...are identified, AIRUSE aims at developing and testing the efficiency of specific and non-specific measures to improve urban air quality. This article reports the results of the source apportionment of PM10 and PM2.5 conducted at three urban background sites (Barcelona, Florence and Milan, BCN-UB, FI-UB and MLN-UB), one suburban background site (Athens, ATH-SUB) and one traffic site (Porto, POR-TR). After collecting 1047 PM10 and 1116 PM2.5 24 h samples during 12 months (from January 2013 on) simultaneously at the five cities, these were analysed for the contents of OC, EC, anions, cations, major and trace elements and levoglucosan. The USEPA PMF5 receptor model was applied to these data sets in a harmonized way for each city. The sum of vehicle exhaust (VEX) and non-exhaust (NEX) contributes between 3.9 and 10.8 µg m−3 (16–32 %) to PM10 and 2.3 and 9.4 µg m−3 (15–36 %) to PM2.5, although a fraction of secondary nitrate is also traffic-related but could not be estimated. Important contributions arise from secondary particles (nitrate, sulfate and organics) in PM2.5 (37–82 %) but also in PM10 (40–71 %), mostly at background sites, revealing the importance of abating gaseous precursors in designing air quality plans. Biomass burning (BB) contributions vary widely, from 14–24 % of PM10 in POR-TR, MLN-UB and FI-UB, 7 % in ATH-SUB, to < 2 % in BCN-UB. In PM2.5, BB is the second most important source in MLN-UB (21 %) and in POR-TR (18 %), the third one in FI-UB (21 %) and ATH-SUB (11 %), but is again negligible (< 2 %) in BCN-UB. This large variability among cities is mostly due to the degree of penetration of biomass for residential heating. In Barcelona natural gas is very well supplied across the city and is used as fuel in 96 % of homes, while in other cities, PM levels increase on an annual basis by 1–9 µg m−3 due to biomass burning influence. Other significant sources are the following. – Local dust, 7–12 % of PM10 at SUB and UB sites and 19 % at the TR site, revealing a contribution from road dust resuspension. In PM2.5 percentages decrease to 2–7 % at SUB-UB sites and 15 % at the TR site. – Industry, mainly metallurgy, contributing 4–11 % of PM10 (5–12 % in PM2.5), but only at BCN-UB, POR-TR and MLN-UB. No clear impact of industrial emissions was found in FI-UB and ATH-SUB. – Natural contributions from sea salt (13 % of PM10 in POR-TR, but only 2–7 % in the other cities) and Saharan dust (14 % in ATH-SUB, but less than 4 % in the other cities). During high pollution days, the largest sources (i.e. excluding secondary aerosol factors) of PM10 and PM2.5 are VEX + NEX in BCN-UB (27–22 %) and POR-TR (31–33 %), BB in FI-UB (30–33 %) and MLN-UB (35–26 %) and Saharan dust in ATH-SUB (52–45 %). During those days, there are also quite important industrial contributions in BCN-UB (17–18 %) and local dust in POR-TR (28–20 %).
Chemical compositions of atmospheric fine particles like PM2.5 prove harmful to human health, particularly to cardiopulmonary functions. Multifaceted health effects of PM2.5 have raised broader, ...stronger concerns in recent years, calling for comprehensive environmental health-risk assessments to offer new insights into air-pollution control. However, there have been few studies adopting local air-quality-monitoring datasets or local coefficients related to PM2.5 health-risk assessment. This study aims to assess health effects caused by PM2.5 concentrations and metal toxicity using epidemiological and toxicological methods based on long-term (2007–2017) hourly monitoring datasets of PM2.5 concentrations in four cities of Taiwan. The results indicated that (1) PM2.5 concentrations and hazardous substances varied substantially from region to region, (2) PM2.5 concentrations significantly decreased after 2013, which benefited mainly from two actions against air pollution, i.e., implementing air-pollution-control strategies and raising air-quality standards for certain emission sources, and (3) under the condition of low PM2.5 concentrations, high health risks occurred in eastern Taiwan on account of toxic substances adsorbed on PM2.5 surface. It appears that under the condition of low PM2.5 concentrations, the results of epidemiological and toxicological health-risk assessments may not agree with each other. This raises a warning that air-pollution control needs to consider toxic substances adsorbed in PM2.5 and region-oriented control strategies are desirable. We hope that our findings and the proposed transferable methodology can call on domestic and foreign authorities to review current air-pollution-control policies with an outlook on the toxicity of PM2.5.
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