Carbon Characterization of Size-Segregated Particulate Matters (PMs) in Residential and Educational Areas in Padang City, Indonesia

Size-segregated of particulate matter (PM) including PM0.1 at two different sites, i.e., educational (EA) and residential (RA) areas in Padang city, Indonesia were sampled by using a cascade type air sampler for 24 hours with the average flowrate 40 l/m throughout three weeks (March, 08th-25th 2018). Carbonaceous components were analyses by a carbon analyzer following the IMPROVE_TOR protocol. Average PM2.5 and PM10 concentrations in RA were higher than those in EA while being below the NAAQS of Indonesia. However, it was much higher compared to the WHO limit for 24 hours in RA. OC was the dominant fraction in TC. OC/EC ratio ranging from 2.4 to 33.0 was similar at both sites, suggesting the OC was emitted from various sources. Char-EC and soot-EC ratio were founded to be minimized for PM0.1 (0.40 ± 0.27 and 0.39 ± 0.39, respectively at each site), indicating a more influence of burning of fossil fuel as vehicles exhaust and coal combustion. The transboundary influence of open biomass burning was not so significant although it cannot be ignored.

Daytime-nighttime variations in the concentration of PM_(0.1) carbonaceous particles during a biomass fire episode in Chiang Mai,Thailand

Carbonaceous aerosols affect air quality adversely,affect global warming,and human health.However,our understanding of the impact of ultrafine(PM_(0.1))carbonaceous particulate matter is incomplete,particularly the effects during haze episodes.This study monitored diurnal variations in PM_(0.1) in Chiang Mai,Thailand,from March to April 2020.We investigated carbonaceous PM_(0.1) collected by an ambient nano-sampler and evaluated their effect by using a carbon analyzer(IMPROVE_TOR).The results showed that burning large open areas in the dry season was crucial for increasing the particle mass concentration because of the large open burnings that occurred in this area.The majority of biomass fires near the sampling site occurred during the night,which would allow more particles to be released thus resulting in higher concentrations of PM_(0.1).Hence,the release of PM_(0.1) during the night would obviously result in higher concentrations than that during the day.In the eight carbon profiles,organic carbon 3(OC3)was predicted to be a marker of biomass fires.The carbon indices displayed that PM_(0.1) was influenced by biomass burning both daytime and nighttime.The findings reported herein should be of great impor-tance in terms of establishing biomass burning control policies for mitigating heavy haze pollution in Thailand and elsewhere.

Fine and ultrafine particle- and gas-polycyclic aromatic hydrocarbons affecting southern Thailand air quality during transboundary haze and potential health effects

Distribution of PM_(0.1),PM_(1) and PM_(2.5) particle-and gas-polycyclic aromatic hydrocarbons(PAHs)during the 2019 normal,partial and strong haze periods at a background location in southern Thailand were investigated to understand the behaviors and carcinogenic risks.PM1 was the predominant component,during partial and strong haze periods,accounting for 45.1% and 52.9% of total suspended particulate matter,respectively,while during normal period the contribution was only 34.0%.PM_(0.1) concentrations,during the strong haze period,were approximately 2 times higher than those during the normal period.Substantially increased levels of particle-PAHs for PM_(0.1),PM_(1) and PM_(2.5) were observed during strong haze period,about 3,5 and 6 times higher than those during normal period.Gas-PAH concentrations were 10 to 36 times higher than those of particle-PAHs for PM_(2.5).Average total Benzo[a]Pyrene Toxic Equivalency Quotients(BaP-TEQ)in PM_(0.1),PM_(1) and PM_(2.5) during haze periodswere about 2–6 times higher than in the normal period.The total accumulated Incremental Lifetime Cancer Risks(ILCRs)in PM_(0.1),PM_(1) and PM_(2.5) for all the age-specific groups during the haze effected scenario were approximately 1.5 times higher than those in nonhaze scenario,indicating a higher potential carcinogenic risk.These observations suggest PM_(0.1),PM_(1) and PM_(2.5) were the significant sources of carcinogenic aerosols and were significantly affected by transboundary haze from peatland fires.This leads to an increase in the volume of smoke aerosol,exerting a significant impact on air quality in southern Thailand,as well as many other countries in lower southeast Asia.

Emissions of particulate matter and associated polycyclic aromatic hydrocarbons from agricultural diesel engine fueled with degummed,deacidified mixed crude palm oil blends

Mixed crude palm oil （MCPO）, the mixture of palm fiber oil and palm kernel oil, has become of great interest as a renewable energy source. It can be easily extracted from whole dried palm fruits. In the present work, the degummed, deacidified MCPO was blended in petroleum diesel at portions of 30% and 40% by volume and then tested in agricultural diesel engines for long term usage. The particulates from the exhaust of the engines were collected every 500 hr using a four-stage cascade air sampler. The 50% cut-off aerodynamic diameters for the first three stages were 10, 2.5 and 1μm, while the last stage collected all particles smaller than 1 μm. Sixteen particle bounded polycyclic aromatic hydrocarbons （PAHs） were analyzed using a high performance liquid chromatography. The results indicated that the size distribution of particulate matter was in the accmnulation mode and the pattern of total PAHs associated with fine-particles （〈 1 μm） showed a dominance of larger molecular weight PAHs （4--6 aromatic rings）, especially pyrene. The mass median diameter, PM and total PAH concentrations decreased when increasing the palm oil content, but increased when the running hours of the engine were increased. In addition, Commercial petroleum diesel （PB0） gave the highest value of carcinogenic potency equivalent （BaPeq） for all particle size ranges. As the palm oil was increased, the; BaPeq decreased gradually. Therefore the degununed-deacidified MCPO blends are recommended for diesel substitute.

Chemical characteristics of size-resolved aerosols in winter in Beijing

Size-resolved aerosols were continuously collected by a Nano Sampler for 13 days at an urban site in Beijing during winter 2012 to measure the chemical composition of ambient aerosol particles. Data collected by the Nano Sampler and an ACSM（Aerodyne Aerosol Chemical Speciation Monitor） were compared. Between the data sets,similar trends and strong correlations were observed,demonstrating the validity of the Nano Sampler. PM10 and PM2.5concentrations during the measurement were 150.5 ± 96.0 μg/m3（mean ± standard variation）and 106.9 ± 71.6 μg/m3,respectively. The PM2.5/PM10 ratio was 0.70 ± 0.10,indicating that PM2.5dominated PM10. The aerosol size distributions showed that three size bins of 0.5–1,1–2.5 and 2.5–10 μm contributed 21.8%,23.3% and 26.0% to the total mass concentration（TMC）,respectively. OM（organic matter） and SIA（secondary ionic aerosol,mainly SO42-,NO3-and NH4＋） were major components of PM2.5. Secondary compounds（SIA and secondary organic carbon） accounted for half of TMC（about 49.8%） in PM2.5,and suggested that secondary aerosols significantly contributed to the serious particulate matter pollution observed in winter. Coal burning,biomass combustion,vehicle emissions and SIA were found to be the main sources of PM2.5. Mass concentrations of water-soluble ions and undetected materials,as well as their fractions in TMC,strikingly increased with deteriorating particle pollution conditions,while OM and EC（elemental carbon） exhibited different variations,with mass concentrations slightly increasing but fractions in TMC decreasing.

Characteristics of nanoparticles emitted from burning of biomass fuels

The characteristics of the particles of the smoke that is emitted from the burning ofbiomass fuels were experimentally investigated using a laboratory-scale tube furnace and different types of biomass fuels： rubber wood, whole wood pellets and rice husks. Emitted amounts of particles, particle-bound polycyclic aromatic hydrocarbons （PAHs） and water-soluble organic carbon （WSOC） are discussed relative to the size of the emitted particles, ranging to as small as nano-size （〈70 nm）, and to the rate of heating rate during combustion, differential thermal analysis （DTA） and thermogravimetric analysis （TG） techniques were used to examine the effect of heating rate and biomass type on combustion behaviors relative to the characteristics of particle emissions. In the present study, more than 30% of the smoke particles from the burning ofbiomass fuel had a mass that fell within a range of 〈 100 nm. Particles smaller than 0.43 μm contributed greatly to the total levels of toxic PAHs and WSOC. The properties of these particles were influenced by the fuel component, the combustion conditions, and the particle size. Although TC--DTA results indicated that the heating rate in a range of 10-20℃did not show a significant effect on the combustion properties, there was a slight increase in the decomposition temperature as heating rate was increased. The nano-size particles had the smallest fraction of particle mass and particle-bound PAHs, but nonetheless these particles registered the largest fraction of particle-bound WSOC.

Influence of agricultural activities,forest fires and agro-industries on air quality in Thailand

Annual and monthly-based emission inventories in northern, central and north-eastern provinces in Thailand, where agriculture and related agro-industries are very intensive,were estimated to evaluate the contribution of agricultural activity, including crop residue burning, forest fires and related agro-industries on air quality monitored in corresponding provinces. The monthly-based emission inventories of air pollutants, or, particulate matter（PM）, NOx and SO2, for various agricultural crops were estimated based on information on the level of production of typical crops： rice, corn, sugarcane, cassava, soybeans and potatoes using emission factors and other parameters related to country-specific values taking into account crop type and the local residue burning period. The estimated monthly emission inventory was compared with air monitoring data obtained at monitoring stations operated by the Pollution Control Department, Thailand（PCD） for validating the estimated emission inventory. The agro-industry that has the greatest impact on the regions being evaluated, is the sugar processing industry, which uses sugarcane as a raw material and its residue as fuel for the boiler. The backward trajectory analysis of the air mass arriving at the PCD station was calculated to confirm this influence. For the provinces being evaluated which are located in the upper northern, lower northern and northeast in Thailand, agricultural activities and forest fires were shown to be closely correlated to the ambient PM concentration while their contribution to the production of gaseous pollutants is much less.