scholarly journals A homogenized daily <i>in situ</i> PM<sub>2.5</sub> concentration dataset from national air quality monitoring network in China

2020 ◽  
Author(s):  
Kaixu Bai ◽  
Ke Li ◽  
Chengbo Wu ◽  
Ni-Bin Chang ◽  
Jianping Guo
Keyword(s):  
Air Quality ◽  
Monitoring Network ◽  
Ambient Air ◽  
Quality Monitoring ◽  
Homogeneity Test ◽  
Air Quality Monitoring ◽  
Haze Pollution ◽  
Temporal Coverage ◽  
Pm2.5 Concentration

Abstract. In situ PM2.5 concentration observations have long been used as critical data sources in haze related studies. Due to the frequently occurred haze pollution episodes, China started to establish the national ambient air quality monitoring network in 2012 but without providing a data download interface to the public. In this study, a five-year long homogenized daily in situ PM2.5 concentration dataset was generated on the basis of discrete data records retrieved from the China National Environmental Monitoring Center (CNEMC) via a web crawler. A set of methods for the purposes of gap filling, data merging, homogeneity test, and bias correction were geared up seamlessly to improve the data integrity and to make essential adjustments to the inherent discontinues detected in each PM2.5 concentration record. After excluding those records with limited temporal coverage, a dataset including 1,309 long-term coherent PM2.5 concentration time series at a daily resolution between 2015 and 2019 was carefully compiled. This is the first thrust to homogenize in situ PM2.5 observations in China. The trend estimations derived from the homogenized dataset indicate a spatially homogeneous decreasing tendency of PM2.5 across China at a mean rate of about −7.6 % per year from 2015 to 2019. Compared with the raw PM2.5 concentration dataset, the homogenized dataset not only has a complete temporal coverage but is more consistent over space and time. This homogenized daily in situ PM2.5 concentration dataset is publicly accessible at https://doi.org/10.1594/PANGAEA.917557, which can be used as a significant data source for satellite-based PM2.5 concentration mapping, population exposure risk assessment, and air quality monitoring and management.

scholarly journals A homogenized daily in situ PM<sub>2.5</sub> concentration dataset from the national air quality monitoring network in China

2020 ◽  
Vol 12 (4) ◽  
pp. 3067-3080
Author(s):  
Kaixu Bai ◽  
Ke Li ◽  
Chengbo Wu ◽  
Ni-Bin Chang ◽  
Jianping Guo
Keyword(s):  
Air Quality ◽  
Monitoring Network ◽  
Change Point Detection ◽  
Quality Monitoring ◽  
Data Series ◽  
Air Quality Monitoring ◽  
Web Crawler ◽  
Haze Pollution ◽  
Pm2.5 Concentration

Abstract. In situ PM2.5 concentration observations have long been used as critical data sources in haze-related studies. Due to the frequently occurring haze pollution events, China started to regularly monitor PM2.5 concentration nationwide from the newly established air quality monitoring network in 2013. Nevertheless, the acquisition of these invaluable air quality samples is challenging given the absence of a publicly available data download interface. In this study, we provided a homogenized in situ PM2.5 concentration dataset that was created on the basis of hourly PM2.5 data retrieved from the China National Environmental Monitoring Center (CNEMC) via a web crawler between 2015 and 2019. Methods involving missing value imputation, change point detection, and bias adjustment were applied sequentially to deal with data gaps and inhomogeneities in raw PM2.5 observations. After excluding records with limited samples, a homogenized PM2.5 concentration dataset comprising of 1309 5-year long PM2.5 data series at a daily resolution was eventually compiled. This is the first attempt to homogenize in situ PM2.5 observations in China. The trend estimations derived from the homogenized dataset indicate a spatially homogeneous decreasing tendency of PM2.5 across China at a mean rate of about −7.6 % per year from 2015 to 2019. In contrast to raw PM2.5 observations, the homogenized data record not only has complete data integrity but is more consistent over space and time. This homogenized daily in situ PM2.5 concentration dataset is publicly accessible at https://doi.org/10.1594/PANGAEA.917557 (Bai et al., 2020a) and can be applied as a promising dataset for PM2.5-related studies such as satellite-based PM2.5 mapping, human exposure risk assessment, and air quality management.

Prediction of PM2.5 concentration based on the similarity in air quality monitoring network

2018 ◽  
Vol 137 ◽  
pp. 11-17 ◽  
Author(s):  
Hong-di He ◽  
Min Li ◽  
Wei-li Wang ◽  
Zhan-yong Wang ◽  
Yu Xue
Keyword(s):  
Air Quality ◽  
Monitoring Network ◽  
Quality Monitoring ◽  
Air Quality Monitoring ◽  
Pm2.5 Concentration

scholarly journals Air quality at bus stop microenvironments in a Metro Vancouver urban and suburban area

2014 ◽  
Author(s):  
Erin Nielsen ◽  
BCIT School of Health Sciences, Environmental Health ◽  
Bobby Sidhu
Keyword(s):  
Air Quality ◽  
Monitoring Network ◽  
Ambient Air ◽  
The Other ◽  
Quality Monitoring ◽  
Small Scale ◽  
Air Quality Monitoring ◽  
Ambient Air Quality ◽  
Bus Stop ◽  
Metro Vancouver

  BACKGROUND Those commuters waiting in small-scale transportation microenvironments, such as bus stops, can be exposed to levels of pollution higher than what is registered by ambient air quality monitoring stations. In addition, historically, those commuting in urban areas experience greater exposure to air pollutants than those commuting in suburban or rural areas, due to the nature of the environment. Little quantitative research has been conducted in the Metro Vancouver area regarding air quality in small scale transportation microenvironments. OBJECTIVES The aim of this study was to assess the differences in commuter exposure during AM Peak and PM Peak periods between an urban (Vancouver) and suburban (Ladner) bus stop. Furthermore, results were to be compared to the Metro Vancouver 24 hour rolling average objective as well as nearby Lower Fraser Valley (LFV) Ambient Air Quality Monitoring Network stations. METHODS The author measured particulate matter (PM) 2.5 (particulate matter ≤ 2.5 μm in aerodynamic diameter), using the DustTrakTM Aerosol Monitor 8520 between January 6, 2014 and January 21, 2014 on 12 weekdays, from 6:30am to 7:00am and 5:00pm to 5:30pm, at Stop #55165 Northbound Harvest Dr at Ladner Trunk Rd in Ladner, BC and from Stop #50043 Burrard Stn Bay1 in Vancouver, BC. In addition, meteorological conditions, traffic density, bus volume, and other observations were taken during sampling periods. RESULTS The author found that average PM2.5 exposures were highest during the morning in Ladner (μ=34.38667μg/m3) and lowest during the morning in Vancouver (μ=13.44 μg/m3). In addition, there was a statistically significant difference (p<0.05) between Vancouver AM and the other groups (Ladner AM, Ladner PM [μ=28.07778 μg/m3], and Vancouver PM [μ=30.16667 μg/m3]), but the other groups were not significantly different from each other. Furthermore, the author found that the Vancouver AM average (μ=13.44 μg/m3) was below the Metro Vancouver 24 hour rolling average (25μg/m3) while all other groups (Ladner AM, Ladner PM, and Vancouver PM) exceeded this average. Lastly, when comparing all groups to the AM and PM hourly averages of their respective LFV Air Quality Monitoring Network stations (Ladner AM and PM vs. Tsawwassen AM and PM and Vancouver AM and PM vs. Kitsalano AM and PM), the author found that all groups averages exceeded the hourly averages of their respective stations. CONCLUSION Commuters’ peak hour exposures were significantly influenced by different microenvironments and were found to be higher than the ambient PM2.5 levels registered by the respective LFV Air Quality Monitoring Network stations. In order to address this, Metro Vancouver should implement personal exposure assessments, especially near roadways, to obtain actual levels of exposure to pollutants, such as PM2.5, by their residents. In this way, acute and chronic health outcome risks to air pollution can be better understood.  

scholarly journals Understanding Spatial Variability of Air Quality in Sydney: Part 1—A Suburban Balcony Case Study

Atmosphere ◽  
2019 ◽  
Vol 10 (4) ◽  
pp. 181 ◽  
Author(s):  
Jack Simmons ◽  
Clare Paton-Walsh ◽  
Frances Phillips ◽  
Travis Naylor ◽  
Élise-Andrée Guérette ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
Air Quality ◽  
Monitoring Network ◽  
Ambient Air ◽  
Companion Paper ◽  
Quality Monitoring ◽  
Urban Landscapes ◽  
Good Representation ◽  
Air Quality Monitoring ◽  
Oxides Of Nitrogen

There is increasing awareness in Australia of the health impacts of poor air quality. A common public concern raised at a number of “roadshow” events as part of the federally funded Clean Air and Urban Landscapes Hub (CAUL) project was whether or not the air quality monitoring network around Sydney was sampling air representative of typical suburban settings. In order to investigate this concern, ambient air quality measurements were made on the roof of a two-storey building in the Sydney suburb of Auburn, to simulate a typical suburban balcony site. Measurements were also taken at a busy roadside and these are discussed in a companion paper (Part 2). Measurements made at the balcony site were compared to data from three proximate regulatory air quality monitoring stations: Chullora, Liverpool and Prospect. During the 16-month measurement campaign, observations of carbon monoxide, oxides of nitrogen, ozone and particulate matter less than 2.5-µm diameter at the simulated urban balcony site were comparable to those at the closest permanent air quality stations. Despite the Auburn site experiencing 10% higher average carbon monoxide amounts than any of the permanent air quality monitoring sites, the oxides of nitrogen were within the range of the permanent sites and the pollutants of greatest concern within Sydney (PM2.5 and ozone) were both lowest at Auburn. Similar diurnal and seasonal cycles were observed between all sites, suggesting common pollutant sources and mechanisms. Therefore, it is concluded that the existing air quality network provides a good representation of typical pollution levels at the Auburn “balcony” site.

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