Liquefied Petroleum Gas Usage Research Articles

LPG gas leakage detection using ESP32

This research paper presents the development of an LPG gas detection system utilizing the capabilities of the ESP32 microcontroller and email notification functionalities. Liquefied Petroleum Gas (LPG), a widely used fuel source, poses a significant threat due to potential fire and explosion hazards in case of leaks. This project addresses this concern by proposing a cost-effective and user-friendly solution for early leak detection. The system employs an MQ-series sensor specifically designed for LPG detection. The sensor's output voltage changes in response to LPG concentration in the surrounding air. This data is acquired by the ESP32 microcontroller and processed to trigger email notifications when gas levels exceed a pre-defined threshold indicative of a potential leak. This allows for remote monitoring and prompt intervention, potentially mitigating safety risks associated with LPG usage in homes and industries. The paper further discusses the system's functionality, development process, and potential applications, along with suggestions for future improvements. Keywords— LPG gas detection, ESP32, MQ-series sensor, email notification, leak detection, safety system, Internet of Things (IoT), microcontroller, sensor data acquisition

Characterization and source apportionment of volatile organic compounds in Hong Kong: A 5-year study for three different archetypical sites

Initial success has been achieved in Hong Kong in controlling primary air pollutants, but ambient ozone levels kept increasing during the past three decades. Volatile organic compounds (VOCs) are important for mitigating ozone pollution as its major precursors. This study analyzed VOC characteristics of roadside, suburban, and rural sites in Hong Kong to investigate their compositions, concentrations, and source contributions. Here we show that the TVOC concentrations were 23.05 ± 13.24, 12.68 ± 15.36, and 5.16 ± 5.48 ppbv for roadside, suburban, and rural sites between May 2015 to June 2019, respectively. By using Positive Matrix Factorization (PMF) model, six sources were identified at the roadside site over five years: Liquefied petroleum gas (LPG) usage (33%–46%), gasoline evaporation (8%–31%), aged air mass (11%–28%), gasoline exhaust (5%–16%), diesel exhaust (2%–16%) and fuel filling (75–9%). Similarly, six sources were distinguished at the suburban site, including LPG usage (30%–33%), solvent usage (20%–26%), diesel exhaust (14%–26%), gasoline evaporation (8%–16%), aged air mass (4%–11%), and biogenic emissions (2%–5%). At the rural site, four sources were identified, including aged air mass (33%–51%), solvent usage (25%–30%), vehicular emissions (11%–28%), and biogenic emissions (6%–12%). The analysis further revealed that fuel filling and LPG usage were the primary contributors to OFP and OH reactivity at the roadside site, while solvent usage and biogenic emissions accounted for almost half of OFP and OH reactivity at the suburban and rural sites, respectively. These findings highlight the importance of identifying and characterizing VOC sources at different sites to help policymakers develop targeted measures for pollution mitigation in specific areas.

Development of a Smart Monitoring System for Advancing LPG Cylinder Safety and Efficiency in Sub-Saharan Africa

Liquefied Petroleum Gas (LPG) is widely recognized as a safe option for household cooking. However, in settings like Nigeria, within sub-Saharan Africa, hazardous events related to LPG are not uncommon, often resulting from inadequate handling and utilization practices. Despite LPG's growing popularity for its sustainability and efficiency, safety concerns persist. This study introduces a smart system tailored to boost gas cylinder safety and efficiency. This system incorporates a compact and robust smart platform that integrates various smart components, provides real-time LPG level information, a load cell is available to continuously monitor LPG levels within the cylinder and issues alert upon reaching predefined thresholds. Furthermore, the system can detect gas leaks, promptly alerting users via a buzzer and LEDs. It is recommended for deployment in households, offices, and industrial environments, ensuring safety, convenience, and effectiveness in LPG usage. This research makes a notable contribution to LPG utilization, presenting an innovative solution to the challenges intrinsic to its application.

Analyzing the safety implications of the upsurge in domestic usage of liquefied petroleum gas (LPG) in Nigeria

The rapid rise in domestic Liquefied Petroleum Gas (LPG) usage in Nigeria signifies a transformative shift towards cleaner energy. This abstract encapsulates a thorough analysis delving into the safety implications linked to this transition. Through meticulous exploration of LPG usage, safety practices, regulations, and stakeholder perspectives, the study aims to illuminate multifaceted safety dimensions in Nigeria. Employing mixed methods, including surveys and interviews, the research offers a holistic view of LPG safety dynamics. Quantitative data of 200 households across the six geo-political zones indicates increasing LPG adoption, highlighting gaps in safety awareness and compliance. Qualitative insights shed light on challenges faced by users, experts, and regulators, providing a nuanced outlook on safety concerns and potential solutions. Key findings underscore the role of safety awareness in shaping user practices and the need for robust regulations for consistent safety enforcement. Stakeholder input emphasizes collaboration against counterfeit equipment and standardized safety training. Recommendations include targeted awareness campaigns, stronger regulations, and industry-user partnerships to bolster LPG safety. The research holds far-reaching implications for policies, industry practices, and public engagement. Amid Nigeria's pursuit of sustainable energy solutions, addressing safety implications of surging LPG usage becomes crucial. This abstract offers a glimpse into a comprehensive exploration aiming to contribute to a safer LPG landscape, harnessing cleaner energy benefits while prioritizing Nigerian households' well-being.

Direct and indirect air pollutant reductions as co-benefits of the energy transition toward carbon-neutrality in India's residential sector

With increasing air pollution, exposure to air pollutants is becoming a critical health and environmental issue all over the world. In case of India, due to significant differences in the economic status and energy consumption characteristics, substantial variation in the air pollutant emissions is observed across Indian states in urban and rural areas. This study aims at developing a residential sector model to project CO2 emissions up to 2070, leading India's progress towards carbon-neutrality, and evaluating the dual benefits of reducing the aforesaid emissions. A bottom-up optimization model is used to analyze these emission projections for greenhouse gases (GHGs) and air pollutants across Indian states in rural and urban areas. Further, to evaluate the effects of Indian government policy, various mitigation scenarios are analyzed, which capture the energy transition and direct and indirect emissions in India's slow, medium, and fast-developing states. Rapid energy transition in India doubles the total energy consumption in the business-as-usual (BAU) scenario from 2010 to 2070. Consumption of traditional biomass and coal energy sources dramatically falls, and advanced energy sources such as liquefied petroleum gas (LPG) and electricity are adopted. Energy transitions help decrease the vulnerability to harmful direct air pollutants such as black carbon (BC), organic carbon (OC) and particulate matter (PM) among rural households. There are serious tradeoffs, however, as increased usage of LPG and electricity may raise total CO2, SO2, and NOX emissions. Higher LPG consumption leads to a more than two-fold increase in CO2 emissions by 2070, compared to 2020 in residential sector. By pursuing carbon-neutrality through a renewable electricity transition, the most ambitious scenario in this study, India could reduce CO2, SO2, NOX, and BC emissions by 67%, 87%, 89%, and 99%, respectively, from the 2070 BAU levels.

Supply-side factors of LPG adoption and usage frequency in Ghana: Assessing the validity of subjective distance to refill

Despite numerous policy efforts to promote the transition to clean cooking fuels, the use of solid cooking fuel persists in developing countries. The scenario calls for a study on the factors influencing the adoption of clean cooking fuels. Hence, this study investigates the supply-side determinants of liquefied petroleum gas (LPG) adoption and usage frequency in Ghana. We conduct a survey among 904 households and 19 LPG refill stations and collect self-reported and geolocational data in the Ga South municipality and Ada West districts of Ghana to compare the validity of the subjective and objective measures of distance to refill stations. We find that the distance to refill stations negatively influences LPG's adoption and usage frequency, and the result is robust across different measures of distance. However, the provision of multiple services at refill stations increases household LPG use. Other key factors influencing usage frequency include policy interventions as well as behavioral and socio-economic characteristics of households. Our results support the validity of subjective estimates by respondents on the distance traveled to access a refill station. These findings have significant policy implications, particularly for developing countries facing challenges in infrastructure for the LPG distribution.

Energy and exergy based study on a box type solar cooker coupled with a Fresnel lens magnifier

ABSTRACT The variation of energy and exergy efficiency of a Box-type solar cooker (BTSC) incorporated with a Fresnel lens magnifier (FLMG) is evaluated in this study. The comparison in energy and exergy efficiency was investigated in the absence and presence of the FLMG to determine the efficiency variation of the BTSC by addition of the FLMG. With the implementation of FLMG, the average values of energy and exergy efficiencies had increased by 10% and 8.52%, respectively. The magnitude of energy efficiency with and without FLMG decreased with time, whereas the exergy efficiency enhanced with time for both cases. The manuscript discusses the effect of different thermodynamic parameters like temperature difference, energy and exergy output, absorber mean plate temperature, and heat losses in the modified cooker. The total heat loss coefficient ranged from 5.48 to 8.44 W/m2K and depended on the variation of wind velocity. The maximum heat loss and mean plate temperature were found to be 120 kJ and 128.3°C, respectively. The time for sensible heating was reduced by 16 mins by the implementation of the FLMG. The addition of the lens showed an increase in the Area concentration ratio (AR) of the BTSC by 48.7%. By comparing the cost and energy usage of LPG (Liquefied Petroleum Gas), the payback period and the quantity of carbon dioxide reduced per month were calculated as 3.19 years and 8.265 kg, respectively.

Characteristics and sources of volatile organic compounds during summertime in Tai'an, China

Continuous measurements of volatile organic compounds (VOCs) were conducted at an urban site in Tai'an, Shandong province of China from 15 May to 10 June 2019. The concentration of total VOCs (TVOCs) was 28.73 ± 15.20 ppbv, and oxygenated VOCs (OVOCs) comprised the dominant proportion (46.4%) among five VOC groups. The most abundant VOC species was formaldehyde, followed by propane, ethane, acetaldehyde, acetone and ethylene. Six VOC sources were identified by positive matrix factorization (PMF) model, including coal combustion (26.2%), OVOCs-related source (20.2%), liquefied petroleum gas (LPG) usage (18.9%), vehicle emission (17.1%), biogenic source (11.1%) and solvent usage (6.5%). The results of conditional bivariate probability function (CBPF) showed that LPG usage, vehicle exhaust and solvent usage were mainly affected by local emissions, while other three sources were greatly affected by regional transmission. Based on the China Ambient Air Quality Standard, O3 episode and non-O3 episode days were identified, and the concentrations of TVOCs were 32.80 ± 15.78 ppbv (O3 episode days) and 24.01 ± 14.47 ppbv (non-O3 episode days), respectively. During different O3 pollution episodes, OVOCs contributed the highest proportion to VOC concentration and ozone formation potential (OFP), while aromatics contributed the greatest potential for secondary organic aerosol potential (SOAP). Moreover, coal combustion and LPG usage were significantly associated with the increase in VOC pollution on O3 episode days.

Modelling of supply and demand-side determinants of liquefied petroleum gas consumption in peri-urban Cameroon, Ghana and Kenya

Household transitions to cleaner cooking fuels (for example, liquefied petroleum gas (LPG)) have historically been studied from a demand perspective, with clean energy usage expected to increase with improvements in household socio-economic status. Although recent studies demonstrate the importance of supply-side determinants in increasing clean cooking, few large-scale studies have assessed their importance quantitatively, relative to demand-related factors. Here, as part of the CLEAN-Air(Africa) study, we examine a population-based survey (n = 5,638) of cooking practices in peri-urban communities within Cameroon, Kenya and Ghana. Multilevel logistic and log-linear regression assessed the demand and supply-side determinants of LPG usage (primary versus secondary fuel) and consumption (kilograms per capita per year), respectively. Supply-side factors (for example, cylinder refill and transportation costs) and the use of single versus multiburner stoves were better predictors than household socio-economic status for both the probability of primarily cooking with LPG and the annual LPG consumption. These results highlight the need for policies that promote LPG supply and stove equipment to meet household needs.

IoT Based LPG Gas Level Detection & Gas Leakage Accident Prevention with Alert System

Liquefied Petroleum Gas (LPG) is widely used for cooking fuel in developing countries for economic reasons, for energy-rich fuel source that contains the higher calorific value, for clean fuel with low carbon emission and for a portable that is available in even the faraway of areas. Therefore the proposed gas leakage detection and monitoring system for the gasoline content present in household LPG cylinder is developed. Usually, the capacity of LPG in cylinder is not determined in an exact manner and a cylinder when the gas is about to empty will be a difficult situation for the one who uses LPG gas for cooking continuously. By using IoT, the information of the near to the empty level of LPG gas in the cylinder will send to the user and the gas refill method by using telephonic ordering can be conducted. The purpose of this research is the detection of gas leakage and monitoring the LPG gas cylinder weight regularly to know the remaining value of gas in the cylinder. When the gas leakage is sensed, the warning signal and alarm sound will be active and also switch on exhaust fan automatically to decrease the gas concentration. The weight of LPG is measured using the load sensor (SEN-10245) and the output of the sensor is connected with Arduino MKR Wifi 1010 microcontroller. The user can know the validity of LPG usage daily because the amount of LPG gas will publish as events and watch them come through in real-time using the Wia IoT cloud platform. Consequently, the user is alerted by giving SMS notification to their mobile phone when the LPG level is critically low (below 20%) by use of the integration function of the Wia IoT platform call Twilio, using its web service APIs. Then by detecting the gas leakage with MQ6 gas sensor, this research work indicates for gas leakage condition and also helps to prevent the LPG gas burst accidents in the home.

A Study of Socio-Economic Impact of Soft Approaches of Climate Adaptation using Changing Fuel Practice in Indoor Air at Rural Sites in India

Majority of India’s rural population depends on biomass burning for cooking and heating purposes on traditional cook stoves called Chullah which results into indoor air pollution. The sampling for this study was carried out in two villages of India viz. Budhwada, Madhya Pradesh (M.P.) and Baggi, Himachal Pradesh (H.P.). Both the regions are significantly different in terms of culture, traditions, topography and daily practices and hence this study helped in understanding the contrast between these regions. The concentrations of carbonaceous aerosols viz. OC (Organic Carbon) and EC (Elemental Carbon) were evaluated for different fuel use in four different houses of each village. Introducing the concept of soft approaches, the residents were asked to bring certain changes in their practices by cooking either with solid biomass or Liquefied Petroleum Gas (LPG) as fuel. The overall average concentration of OC was found to be higher for Budhwada (M.P.) at 124.34 ± 34.68 µg/m3 than at Baggi, (H.P.) with value 105.26 ± 35.63 µg/m3 whereas the reverse was true for the average concentration of EC with value 62.98 ± 20.75 µg/m3 at Baggi, (H.P.) and 55.51 ± 15.51 µg/m3 at Budhwada (M.P.). The average OC and EC concentrations from solid biomass fuel (dung cake) burning at Budhwada (M.P.) was respectively higher by 56.14% and 33.57% as compared to the LPG usage. Similarly, in Baggi (H.P.) village with LPG usage, a significant reduction was observed in OC and EC concentrations (76.69% and 70.10% respectively) when compared with fuelwood burning. House-wise and time-wise variations of carbonaceous aerosols at both the sites confirmed that their concentrations are lower in houses with greater ventilation and higher in cooking times (morning and evening). In Budhwada (M.P.), the concentrations of K+, Ca2+ and SO42- ions decreased significantly from dung cake to LPG use by 67.91%, 76.98% and 51.85% respectively. In Baggi (H.P.), K+ ion concentration was decreased by 63.4% from fuelwood to LPG use. A questionnaire survey conducted on the residents also corroborated the above findings where the residents agreed that LPG use has health benefits over solid biomass fuel usage but the challenges such as supply of LPG into rural interiors, financial feasibility, etc. were of serious concern. Also, changing the contemporary mindset of rural population is a challenging task.

Photochemical ozone pollution in five Chinese megacities in summer 2018

To investigate photochemical ozone (O3) pollution in urban areas in China, O3 and its precursors and meteorological parameters were simultaneously measured in five megacities in China in summer 2018. Moderate wind speeds, strong solar radiation and high temperature were observed in all cities, indicating favorable meteorological conditions for local O3 formation. However, the unusually frequent precipitation caused by typhoons reaching the eastern coastline resulted in the least severe air pollution in Shanghai. The highest O3 level was found in Beijing, followed by Lanzhou and Wuhan, while relatively lower O3 value was recorded in Chengdu and Shanghai. Photochemical box model simulations revealed that net O3 production rate in Lanzhou was the largest, followed by Beijing, Wuhan and Chengdu, while it was the lowest in Shanghai. Besides, the O3 formation was mainly controlled by volatile organic compounds (VOCs) in most cities, but co-limited by VOCs and nitrogen oxides in Lanzhou. Moreover, the dominant VOC groups contributing to O3 formation were oxygenated VOCs (OVOCs) in Beijing and Wuhan, alkenes in Lanzhou, and aromatics and OVOCs in Shanghai and Chengdu. Source apportionment analysis identified six sources of O3 precursors in these cities, including liquefied petroleum gas usage, diesel exhaust, gasoline exhaust, industrial emissions, solvent usage, and biogenic emissions. Gasoline exhaust dominated the O3 formation in Beijing, and LPG usage and industrial emissions made comparable contributions in Lanzhou, while LPG usage and solvent usage played a leading role in Wuhan and Chengdu, respectively. The findings are helpful to mitigate O3 pollution in China.

Etiological & clinical spectrum of Liquefied Petroleum Gas (LPG) related burns: A three-year study from a tertiary care burn centre in New Delhi

Burns, an endemic public health problem has had a dynamic epidemiology in India, in sync with economic and social changes. In the last decade a major shift of kitchen fuel usage from kerosene to the Liquefied Petroleum Gas has resulted in an increase in the incidence of burns from LPG mishaps. This prospective descriptive study conducted in a tertiary care burn centre in an urban area aims to determine the causes of LPG related burns, its injury profile, identify the population at risk and also to determine the level of knowledge of users regarding the safety issue with LPG usage. In the study LPG burns accounted for 52.3% of the admitted flame burns. On the whole there were 33 incidents of LPG mishaps involving multiple victims. Most common age group affected was 26–50 years. Leakage from larger cylinders was more common and malfunction of valve/regulator was the most common cause. Level of knowledge was dismally low across all socioeconomic strata.Our study highlights impact of changing socioeconomic pattern of the country on burns epidemiology and the glaring lack of public awareness regarding safe management principles.

Factors that Affect the Adoption of Liquefied Petroleum Gas in Kinondoni Municipality, Tanzania

Identification of the factors affecting the adoption of Liquefied Petroleum Gas (LPG) is necessary in creating enabling environment for promoting LPG usage in Tanzania. This paper examines factors that affect the adoption of LPG in the jurisdiction of Kinondoni Municipal Council; one of the five municipalities in the city of Dar es Salaam. A cross-sectional research design, involving 466 households from three wards (Msasani, Kijitonyama and Tandale) was employed to capture qualitative and quantitative data. Content analysis was carried out using the Likert scale to observe perceived factors affecting the adoption of LPG. Chi square test and binary logistic regression were performed to examine the likelihood of the adoption of LPG to occur. The findings suggest that at the micro level, several factors do affect the adoption of LPG, but different individuals have different perceptions based on personal experiences. Uncovered factors include the quantity of sell, household income, household size, and the level of awareness. At the macro level, fuel availability is assumed to play an important role in determining the adoption and usage of LPG. Chi square test shows the association between different variables and LPG usage; while logistic regression reveals two variables—education and household expenditure (proxy for income)—as significant factors. The study recommends that the creation of enabling environment for LPG usage in the municipality should pay more attention to issues related to education and income.

Microfinance for clean cooking: What lessons can be learned for scaling up LPG adoption in Kenya through managed loans?

Liquidity constraints are a key barrier to acquisition and sustained use of clean household energy in resource-poor settings. This study evaluates a pilot microfinance initiative in Kenya to help low-income rural households access liquefied petroleum gas (LPG) for cooking. Program beneficiaries received a six-month loan that covered all equipment costs and was to be repaid in monthly installments. We present results from surveys of beneficiaries (n = 69) after they began using LPG, as well as 332 non-beneficiaries from the same community (to understand how beneficiaries and non-beneficiaries differ in cooking patterns and socioeconomic outcomes). 94% of beneficiaries had repaid their loan in full and on time at the time of data collection. Meanwhile, beneficiaries were more likely than non-beneficiaries to use LPG as their primary cooking fuel (76.8% of beneficiaries versus 38.8% of non-beneficiaries). While 81.1% of beneficiaries who used LPG as their primary cooking fuel reported multiple fuel use, we find beneficiaries increased LPG use by 5.9 h per week with a corresponding decrease of 4.8 h in weekly use of biomass fuel. Our findings suggest that promoting LPG usage through microloans for equipment is likely to be both commercially viable and beneficial to health through decreased use of polluting biomass fuel.

The refill gap: clean cooking fuel adoption in rural India

From 2016 to 2019, the Indian Pradhan Mantri Ujjwala Yojana (PMUY) distributed over 80 million liquefied petroleum gas (LPG) stoves, making it the largest clean cooking program ever. Yet, evidence shows widespread continued use of the traditional chulha, negating the potential health benefits of LPG. Here we use semi-structured interviews with female and male adults to understand the drivers of LPG usage in Mulbagal, Karnataka, the site of a proto-PMUY program. We find that respondents perceive the main value of LPG to be saving time, rather than better health. We also find that norms of low female power in the household, in addition to costs, delay saving for and ordering LPG cylinder refills. Namely, female cooks controlled neither the money nor the mobile phone required to order a timely refill. These factors together contribute to the ‘refill gap’: the period of non-use between refilling cylinders, which may range from days to even months. Our work reveals how gender norms can amplify affordability challenges in low-income households.

Promoting LPG usage during pregnancy: A pilot study in rural Maharashtra, India

Household air pollution from the combustion of biomass and coal is estimated to cause approximately 780,000 premature deaths a year in India. The government has responded by promoting uptake of liquefied petroleum gas (LPG) by tens of millions of poor rural families. Many poor households with new LPG stoves, however, continue to partially use traditional smoky chulhas. Our primary objective was to evaluate three strategies to transition pregnant women in rural Maharashtra to exclusive use of LPG for cooking. We also measured reductions in kitchen concentrations of PM2.5 before and after our interventions. Our core intervention was a free stove, 2 free LPG cylinders (one on loan until delivery), and repeated health messaging. We measured stove usage of both the traditional and intervention stoves until delivery. In households that received the core intervention, an average of 66% days had no indoor cooking on a chulha. In an adjacent area, we evaluated a conditional cash transfer (CCT) based on usage of LPG in addition to the core intervention. Results were less successful, due to challenges implementing the CCT. Pregnant women in a third nearby area received the core intervention plus a maximum of one 14.2 kg cylinder per month of free fuel. In their homes, 90% of days had no indoor cooking on a chulha. On average, exclusive LPG use decreased kitchen concentrations of PM2.5 by approximately 85% (from 520 to 72 μg/m3). 85% of participating households agreed to pay the deposit on the 2nd cylinder. This high purchase rate suggests they valued how the second cylinder permitted continuous LPG supply. A program to increase access to second cylinders may, thus, be a straightforward way to encourage use of clean fuels in rural areas.

Impacts of residential energy consumption on the health burden of household air pollution: Evidence from 135 countries

Knowledge about the links between burden from household air pollution (B-HAP) and residential energy consumption (REC) is essential for optimizing residential energy supply mix and improving the quality of indoor air worldwide. However, the literature on this topic from a perspective of energy transition is still lacking. This study investigates the relationship between the variation in the B-HAP and the structural transition of REC using cross-sectional data of 135 countries during 1990–2015. The results indicate that countries with high B-HAP are clustered in Africa and Asia, which are mainly middle- and low-income countries. Meanwhile, with the structural transition of REC, the global B-HAP has exhibited a decreasing trend. Moreover, the findings show that residential electricity use has a greater impact on B-HAP reduction than other household fuels. Although the impacts of liquefied petroleum gas usage changed considerably during the study period, its contribution to reducing the B-HAP remains highly significant, while household natural gas use exhibited a significant and stable effect on B-HAP reduction. In contrast, solid biomass use showed an increasingly adverse impact on the B-HAP, and the impact of coal use on the B-HAP became statistically significant since 2010, with an increasing trend.

The levels, sources and reactivity of volatile organic compounds in a typical urban area of Northeast China

Air concentrations of volatile organic compounds (VOCs) were continually measured at a monitoring site in Shenyang from 20 August to 16 September 2017. The average concentrations of alkanes, alkenes, aromatics and carbonyls were 28.54, 6.30, 5.59 and 9.78 ppbv, respectively. Seven sources were identified by the Positive Matrix Factorization model based on the measurement data of VOCs and CO. Vehicle exhaust contributed the most (36.15%) to the total propene-equivalent concentration of the measured VOCs, followed by combustion emission (16.92%), vegetation emission and secondary formation (14.33%), solvent usage (10.59%), petrochemical industry emission (9.89%), petrol evaporation (6.28%), and liquefied petroleum gas (LPG) usage (5.84%). Vehicle exhaust, solvent usage and combustion emission were found to be the top three VOC sources for O3 formation potential, accounting for 34.52%, 16.55% and 11.94%, respectively. The diurnal variation of the total VOCs from each source could be well explained by their emission characteristics, e.g., the two peaks of VOC concentrations from LPG usage were in line with the cooking times for breakfast and lunch. Wind rose plots of the VOCs from each source could reveal the possible distribution of the sources around the monitoring site. The O3 pollution episodes during the measurement period were found to be coincident with the elevation of VOCs, which was mainly due to the air parcel from the southeast direction where petrochemical industry emission was found to be dominant, suggesting that the petrochemical industry emission from the southeast was probably a significant cause of O3 pollution in Shenyang.

VOC characteristics, sources and contributions to SOA formation during haze events in Wuhan, Central China

Based on detailed data on 102 volatile organic compounds (VOCs) measured continuously from 2016.10.9 to 2016.11.17 in Wuhan, the VOC characteristics, secondary organic aerosol (SOA) characteristics, SOA formation potential (SOAP), potential source regions, sources and contributions during different haze episodes were analyzed. The total VOC (TVOC) concentrations on clear days (visibility >10 km), slight haze days (visibility of 5–10 km), and severe haze days (visibility <5 km) were 34.87 ± 14.89 ppbv, 45.06 ± 26.69 ppbv, and 49.55 ± 24.82 ppbv, respectively. The SOAP on haze days (447.04 ± 253.85 ppbv) was significantly higher than that on clear days (300.62 ± 138.48 ppbv), and aromatics were the dominant contributors to SOA formation under different visibility conditions, accounting for approximately 97% of the total SOAP. The ratio of ethylbenzene to m/p-xylene (E/X) indicated that atmospheric photochemical reactions were slightly stronger on haze days. The ratio of toluene to benzene (T/B) indicated that vehicle exhaust had significant effects on VOCs, but no significant changes occurred during different haze episodes. The ratio of benzene, toluene, ethylbenzene and xylenes (BTEX) to CO indicated that VOCs from solvent usage in painting/coating and industrial emissions increased with increasing haze pollution. Based on backward trajectories and the potential source contribution function (PSCF), short-distance transport was the main source influencing VOC pollution, especially transport from the southwest. Seven sources were identified by positive matrix factorization (PMF): industrial sources, vehicular exhaust, solvent usage in painting/coating, fuel evaporation, liquefied petroleum gas (LPG) usage, biogenic sources and biomass burning. Moreover, solvent usage in painting/coating, vehicle exhaust and LPG usage were the most important sources that significantly aggravated VOC pollution during haze events. The results can provide references for local governments developing control strategies of VOCs during haze pollution events.